What to consider when you’re thinking about a synchronous condenser

Depending on when and where you want to connect your new solar farm or wind farm, the network service provider or your consultant may tell you that you’ll need a synchronous condenser. That may not be good news, because these machines don’t come cheap and they usually don’t provide a direct revenue stream. What should you do next?

Do you understand why you need a synchronous condenser?

The first step is to understand why you need the synchronous condenser. The inverters at the heart of most solar farms and most modern wind turbines need a strong electricity grid to push their energy into. If the network is not strong, the inverter is likely to fail to switch at the required times, swing against the power system like a pendulum, and distort the waveform, causing harmonics. The synchronous condenser overcomes this, strengthening the power system in the local area by forcing the network voltage into a near-perfect sine wave of the required size. 

Is it possible to predict the need for a synchronous condenser earlier?

There are ways that you can predict at the project pre-feasibility stage that a synchronous condenser might be needed, before the network service provider becomes involved. Take a look at other renewable energy installations that have been constructed recently in the same region; if they needed a synchronous condenser, you almost certainly will too.

Consider where the installation is in the grid, and if the answer to any of the following questions is yes, you will likely need a synchronous condenser: Is your installation remote from all traditional generating stations? Has a large traditional generator shut down in the area recently? Are other generators in the area routinely constrained due to network stability challenges?

Simple calculations can be completed based on information that most network service providers publish on their websites, including network constraints and fault levels. These calculations aren’t always definitive, but they will offer significant insight.

What do you need to specify?

It is best to specify the exact function that the synchronous condenser must achieve. Typically, this means specifying the fault current contribution that is required from the machine and leaving it up to the manufacturer to decide the optimal machine design including the headline MVA rating. Once these headline values have been determined, consider the following questions, each of which has a substantial cost impact:

• How much reactive power do you need the synchronous condenser to absorb? Typically these machines can only absorb approximately half of their headline rating, so don’t ask for too much unless you have deep pockets.
• Do you really need inertia that is greater than the manufacturer’s standard? Synchronous condensers are known for having inertia, but asking for inertia that is greater than the manufacturer’s standard will result in substantial additional cost and usually results in no additional revenue stream.
• The synchronous condenser is being installed to provide system strength, so do you really want it to be able to supply reactive power indefinitely? Perhaps 60 seconds would be enough.

Are some cost savings not worth making?

For a synchronous condenser project, there are some measures that, on the surface, might appear to be potential cost-saving considerations. Can you omit the transformer tap changer? Could the cooling equipment be downsized or even omitted? Can you connect to the station 33 kV busbar? Detailed analysis is needed to answer these questions definitively. In our experience, however, the answers to each question have been emphatically no.

If you need the synchronous condenser to operate close to its rated reactive power absorption limit, you’ll need a transformer tap changer. Similarly, if the machine connects to a 33 kV busbar, fault levels will become unreasonable and an even larger machine will be required.

What’s the best contracting model?

Your choice of contracting model will depend on your appetite for risk and the sensitivity of your schedule. A typical solar or wind farm project is very schedule-sensitive, which suits an all-inclusive turnkey project delivery including everything from civil foundations, fencing and drainage through to integration with the farm’s control system. But this delivery mode comes at a price, and there are few Tier-1 equipment suppliers prepared to take on this model. The lowest cost suppliers will be likely to want to put your machine onto a ship, point it in your general direction, and send you the invoice.

Whatever your contracting model, one of the largest risks to projects is the adequacy of the power system models. You need to be confident that the original equipment manufacturer understands the market operator’s model requirements and has the skills to comply with them.

Can the machine offer economic benefits?

Two possible revenue streams could potentially flow from installing a synchronous condenser. By sizing the synchronous condenser to provide the reactive power required from a solar farm by the electricity rules, it is possible to operate the solar inverters and the main transformer at a higher power factor. This has the potential to increase the power output and consequently the revenue from the farm by up to 7%. A proponent could also install an oversized synchronous condenser and sell the spare system-strengthening capacity to another renewable farm in the same region. In the future, inertia and system-strength markets may evolve in ways that provide direct revenue streams for the synchronous condenser.

Is there an alternative?

The inverters at the heart of most solar farms and most modern wind turbines are changing. Until recently, they have exclusively used a technology called ‘grid-following inverters’, but a newer ‘grid-forming inverter’ is breaking into the market. These inverters are more expensive at the moment, but that’s likely to change rapidly. The newer inverters are much less sensitive to system strength. It is likely that applications will soon emerge in which changing the inverter will eliminate the need for a synchronous condenser. We predict that this could occur for small installations first and evolve over time to include larger renewable farms.

Putting it all together

The most cost-effective projects are often those that link multiple technologies – such as a wind farm with modern wind turbines, static VAr compensators and more than one synchronous condenser. These technologies were not designed to work well together, but with carefully coordinated controls they have done so in practice, providing the required system strength, voltage control and inertia for a successful minimum-cost project.

If you would like to find out more about how Entura can help you overcome electrical challenges for wind farms or solar farms, please contact  David Wilkey on +61 3 6828 9749 or Patrick Pease.

About the author

David Wilkey is Entura’s Principal Consultant, Secondary Electrical Engineering. He has more than 20 years of consulting experience in electrical engineering across Australia and New Zealand, focusing on the delivery of advisory on secondary systems and power systems engineering. David’s expertise spans all areas of electrical engineering with a particular focus on electrical protection, power system studies and rotating electrical machines.

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Keeping international projects moving, even when we’re grounded

With no set date for when life will return to usual after COVID-19, nor any guarantee of whether life will ever return to what we previously knew as ‘usual’ at all, there are very few areas in the consulting life in which we can simply say ‘we’ll wait until this is all over’. Life, and projects, must go on.

Although we can’t avoid the disruption and uncertainty that the coronavirus has unleashed, we can increase our resilience and agility. We can also embrace opportunities to innovate and to create new ways (or reinvigorate old ways) to achieve our goals.

Here, Entura’s Environment and Planning team continue to apply their proactive approach to keeping projects alive in the current circumstances, and explain how they are continuing their activities on two international projects despite the travel restrictions that are making it impossible to visit the project sites.

Old ways for new times – Engaging communities in Tonga

For many countries across the globe, the immediate challenge is building resilience to fight through the pandemic. However, for some small island nations that have managed to stay out of the virus’s path so far, such as Tonga and the Federated States of Micronesia, the concept of resilience has a broader context.

Climate resilience is a core objective, as these nations are feeling the increasing impacts of rising sea levels and more frequent and intense weather events. In this context, robust power infrastructure that is suited to extreme weather is one component of greater resilience, as is transitioning from diesel dependence to higher levels of renewables, which builds greater security of energy supply at a lower longer term financial and environmental cost. More access to stable, reliable and clean electricity is also critical for the health, wellbeing and education of local communities, and is the foundation for economic development. Entura has been fortunate to be involved in some meaningful resilience-building projects in the Pacific, supporting many of our neighbouring nations to implement sustainable energy solutions.

However, with a current project in Tonga, coronavirus has thrown our travel plans into disarray. The challenge we’re facing now is how to continue the planning, engagement and environmental activities required by such a project when we can’t physically get there, can’t hold town hall meetings and can’t host information sessions with locals.

While the pandemic is forcing many practitioners to extend and expand their use of digital forms of engagement (such as websites, Facebook, Twitter, ‘Bang the Table’ or moderated ZOOM-based focus groups), some projects are located in communities that do not enjoy easily available or reliable internet or telephone access. In these cases, such as our project in Tonga, we need to think differently about ways to facilitate engagement from a distance.

For the Tongan project, we’re heading back to basics: the tried and tested solution of providing information on paper. Working with the local project management unit, along with our client, we are designing and implementing a newsletter to be printed in the local language and distributed to regulators and communities. It will provide snapshots of the project, latest updates on scheduling, and will even feature some interviews to provide greater coverage of ongoing community engagement.

As the construction company for the project is, like us, unable to travel internationally at the moment, construction is yet to take place. Nevertheless, we are continuing to facilitate all aspects of the project remotely, such as lining up approvals with regulators, and guiding engagement on the ground. With the help of our Tongan counterparts, we can still keep information and updates flowing despite the physical limitations on our involvement ‘in the flesh’.

Buying time and building partnerships in South-East Asia

Just as COVID-19 started closing borders and halting international travel, our team was reaching the culmination of many weeks planning an impact assessment for a large infrastructure project in South-East Asia. Our discipline experts were about to book their tickets and embark on the journey to site to survey environmental and social impacts. However, we placed the site surveys on hold indefinitely to comply with travel restrictions, ensure the safety of our people and contractors, and not risk spreading the virus in remote communities.

This abrupt shift in our plans afforded us the chance to take a breath, reflect on the project and its broader risks, and then develop an alternative plan to keep progressing aspects of the work that could be done remotely. We are now proactively undertaking desktop approval studies and initial public consultation from our desks. We’re ‘buying time’ now to save time later.

When travel restrictions lift and it is once again safe to physically attend the site, we will be ahead of where we would have been pre-COVID-19. We will better understand potential issues and have a more thorough insight into the local and community context. We’ll have already carefully planned our field studies with more targeted approaches. We’ll be better prepared for stakeholder questions that may arise, and will have already considered ways in which the project might manage challenges and risks going forward.

But there’s something more that we’re seeing emerge in this COVID-19 period. We’re finding that the shared need to adapt to trying times and the mutual desire to find workable solutions is strengthening our relationships with our clients, building even greater trust and collaboration, and it is leading to ‘partnership’ relationships that transcend the more common transactional paradigm of client–consultant. We are working closely together to openly discuss issues and options, and to determine how best to manage emerging challenges to benefit the project.

Would this have happened without COVID-19? Perhaps – but under the usual pressure of timelines, expectations, standardised processes and the drive for efficiency, there isn’t often the same flexibility or space to build different qualities and layers in our relationships or to consider potential issues quite so broadly or creatively.

Will the project benefit from the changes made necessary by COVID-19? Probably – despite the difficulties caused by the limitations on travel, it can only be positive to have had the chance to take the time to more thoroughly and holistically consider all the issues and risks before we proceed to field studies and stakeholder engagement.

Will timelines change significantly because of COVID-19? Not necessarily – we will inevitably lose some months by not being able to go into the field, but we will have ‘bought’ some time by compiling a good portion of the project documentation prior to the field studies, so that the time required in subsequent stages is lessened.

Wherever in the Indo-Pacific region our international projects are located, our clients can be confident that we’re seeking all the ways we can – new or old – to keep making progress in these uncertain and complicated times … and to come through them stronger together.

If you would like to discuss how Entura can help you with your environmental or planning project, please contact us.

Don’t let COVID-19 stop your project

A vital part of the success of all projects, whether they are new or operational, is maintaining progress towards milestones and retaining currency in the social and regulatory realms. How can we achieve this during a global pandemic?

With the COVID-19 crisis affecting people and businesses across the globe, employers and employees alike are racing to find normalcy. Fortunately for Entura, we’ve already been working and collaborating virtually for many years across country and state borders, with dispersed office, client and project locations. So, even though our teams are working from home, it is still business as (mostly) usual, in unusual times!

Although COVID-19 hasn’t thrown us completely, travel restrictions have pushed us to think differently about many of our projects and methods. This is the time to explore proactive ways to ensure projects do not come to a grinding halt or fall off a community’s or regulator’s radar.

Keeping environmental and planning projects moving forward

Entura’s environment and planning team works frequently in the field – lakes, forests, roadsides, development sites and many more – so COVID-19 travel restriction have taken a hit at our ability to undertake survey and monitoring programs or to conduct site visits, but it hasn’t led to tools down.

We may miss out on our chance to hit the frosty outdoors this autumn and winter, but there are still many ways that we can and will continue to make progress and deliver value. It’s about thinking creatively about how we can be proactive. And that means finding measures and activities for the short and medium term that will keep the project moving towards the longer term project milestones and goals (without the anticipated longer term extending into the much further horizon!)

For example, there are proactive things we can do to prepare us better for when we can once again visit the site. We have access to a wide range of data and can undertake thorough desktop investigations early in the project. We will then be able to step on site well prepared and looking to fill knowledge gaps or to verify what should be there. That puts us in a better position to be alert to anything unexpected we might find when we’re physically on site in future. Unusual discoveries and observations will be more pronounced. Such approaches can help shorten project timelines post-COVID-19 compared with the inevitable blowouts that would be caused by downing tools completely.

Policy and regulatory reforms are also still happening across the country – some as a result of COVID-19, others associated with larger reform programs to update antiquated legislation. Our discipline experts continue to engage with the regulators and relevant government agencies and authorities to ensure we understand the nuances of these changes and how they may influence the scope of existing and future projects and programs of work.

More proactive, less reactive

The restrictions caused by COVID-19 have highlighted the need to be proactive so that we can be better positioned for the longer term. It’s natural for a consulting paradigm to tend towards the reactive and process-driven, but this is the time to shift such tendencies.

With a future-focus and forward thinking, we can all seek out proactive solutions to keep projects and processes running as smoothly as possible, to meet any milestones that are still feasible, and to do everything that is reasonably possible in the present circumstances that will minimise delays once the pandemic has eased.

This needs to be a shared process. If as consultants and clients we put our heads together, we can develop shared understandings of the opportunities, risks and issues affecting all parts of the project and all the players involved. With team work and good communication, together we’ll find the most innovative and workable solutions, and together we will survive and thrive.

Beyond the immediate

The circumstances of the pandemic are also an opportunity to think beyond the immediate projects on our desks. This is a great time for our clients to review their projects and environmental and social management practices, to be better positioned for the post-COVID-19 future. This could include being more informed about potential risks or thinking through changes that you could make to your management practices to better address ongoing or emerging issues.

In our next article, we will highlight some of the projects we are currently working on, and how we have adapted them in light of COVID-19. We will also dig down into some of the key regulatory reforms happening across the country, and what implications they may have on projects during the COVID-19 period and beyond.

At Entura, we will continue to respond to government measures as they surface, and we will continue to be here to assist all our clients to better understand the opportunities, risks and issues associated with keeping your project alive during COVID-19.

A message from our team to yours

And to finish on a light note – Entura’s environment and planning team has nimbly settled into their new branch offices, from urban Melbournian set-ups to peri-urban workplaces at the foothills of the majestic kunanyi/Mount Wellington in Tasmania. From our team to you or yours, here are a few handy tips which we have found to help with this transition to working from home:

• Stay connected – drop your colleague or manager a line and ask how they are going, and where possible (bandwidth permitting), turn on the video during your virtual meetings.
• Schedule regular team catch-ups, and why not end the week with an optional virtual gathering to kickstart some weekend banter?
• Don’t be embarrassed if your pets or children make an appearance – it helps lighten the mood and may provide the laugh that someone really needed.
• Get some fresh air before you start work – imitate that commute to work by going for a walk or cycle.

If you would like to discuss how Entura can help you with your environmental or planning project, please contact us.

Pictured, clockwise from top left:

• Senior Social and Stakeholder Consultant, Dr John Cook
• Land Use Planner, Bunfu Yu
• Senior Aquatic Scientist, Dr Malcolm McCausland (and friends)
• Team Leader Environment and Planning, Raymond Brereton
• Senior Environmental Planner, Cameron Amos
• Senior Planning and Environmental Consultant, Scott Rowell (about to head out for a ride)
• Environmental Consultant, Rachael Wheeler

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Engineering – by humans, for humans

When engineers think about the future, do we get so engrossed in the complex technical problems that we don’t attend enough to the human angle?

Engineers have a reputation, whether rightly or wrongly, for being poor communicators, working obsessively and in isolation, and focusing on the immediate goal rather than its impacts on communities. Often, clichés have a basis in truth. If we are going to shift perceptions, we need to start by thinking about the way we work and the leadership we show to the next generation of engineers.

There’s no way we can predict the major developments, challenges or solutions of the next five or six generations of engineering careers. What we should focus on is what we can do right now to lead change in our profession and our communities – and I think the keys are communication, collaboration and community.

Communication

I recently listened to a podcast in which two energy market experts talked with a power system engineer. They discussed all sorts of technical matters relating to frequency and voltage control. I love those topics, but this conversation was limited and uninspiring because the participants simply didn’t have a common language or understanding.

We need to learn to communicate in ways that a variety of people can understand. That will mean better conversations with the people who can help our work have greater impact, and it will help our communities to appreciate the importance of our work in their lives.

It’s too easy for us as a profession to sit at our desks or stand under our hard hats and luxuriate in how clever we are, and then bemoan how so many people have no idea what we do and don’t value our work.

When things that involve engineers go wrong, a flurry of opinions erupts. Failures such as the blackout in South Australia, or the cladding issues at the Grenfell Towers, or issues with airlines or bridges or dams all lead to our communities questioning and debating engineering practice. Engineers tend to try to stay out of this rough and tumble for fear of being misrepresented. Yet maybe it’s better that we do engage where we can, since being misrepresented on a small issue is better than allowing a groundswell of misguided public opinion due to a lack of understanding of engineering principles. 

We need to try to better explain our work and find simple ways to convey the complexities of the decisions that we make. 

Collaboration

The world is far more complex now than it was a century ago – but it is impossible to imagine what level and pace of change future generations will experience. If we want to transform our world or help build a better future, we can’t do it by ourselves. 

Engineering no longer operates in isolation, if it ever did. We must collaborate across the engineering team and across other professional disciplines to achieve truly effective development for our communities. Sometimes we may need to focus a little less on technical delivery as a primary outcome, and increase our recognition of the value gained by engaging successfully with the communities on whom the project relies for success.

Collaboration makes our work more effective, and exposes us to a wider range of inputs and values that we can incorporate into our designs and processes. Engineering can be a leader but it can also be a facilitator for better outcomes when we draw on, listen to and learn from the other experts involved in other aspects of our projects.

Community

Engineering work almost always benefits more people than merely the one who pays the bill. Much of my work is in connecting wind farms and solar farms to the grid. Mostly my work is paid for by the owner of the farm, and while it delivers direct benefits to the owner through return on investment, it also affects everyone connected to the nearby network. It affects the network service provider and market operator, it pays salaries, and it supplies the clean energy that helps the country reduce emissions and meet its international targets. In other words, my work, which may seem intangible, has tangible effects in the real world.

If we agree that our labours produce real impacts, we need to take better care to fully consider the wider consequences of our work, which often has the potential to cause ‘collateral damage’. We can’t build a road or a wind farm without changing the landscape. When we build a machine, it uses energy and may emit pollutants; and it reduces reliance on manual labour, which may put someone out of a job. There may be a risk to lives, livelihoods or the environment if something goes wrong.

Do we always make decisions about these matters with the community front of mind, or do we place our clients on the higher pedestal? This is a tricky area and I’m not espousing a puritanical approach. However, if we knew in 1919 what we know now about lead poisoning, acid rain, greenhouse gases, scarcity and general sustainability principles, what different choices could have been made?

In a time of automation, we need to think about benefits and risks and how they affect our communities. On one occasion early in my career, I designed a controller to turn on and off a couple of compressors at a power station. I wrote some code to balance the run hours. A few months after the new system was commissioned, I asked one of the operators how the system was going, in terms of the run hours management, and he said ‘you’ve done me out of a job’. I hope he was joking. The task he’d been doing wasn’t particularly important, but there was value in having a person who was in tune with the equipment to take care of it, and there was also value in giving that person dignity through work.

My point is that we must keep our communities foremost in our minds as we go about our work. It’s not just about what we produce. It is the way we work and the people we choose to work with and for. Our influence on the development of the next generation of engineers perhaps has more impact on communities than our actual work outputs.

Through communication, collaboration and community, engineering can be both ‘more human’ and ‘for humans’.

About the author

Donald Vaughan is Entura’s Technical Director, Power. He has more than 25 years of experience providing advice on regulatory and technical requirements for generators, substations and transmission systems. Donald specialises in the performance of power systems. His experience with generating units, governors and excitation systems provides a helpful perspective on how the physical electrical network behaves and how it can support the transition to a high renewables environment.

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Congestion and losses: more than a blocked nose for new renewable generation

Anyone who’s ever had a cold understands the discomfort of blocked airways. Congestion challenges, albeit slightly different ones, also face developers of new renewable energy generation.

The nature of powerflows around the grid is changing rapidly with a lot of new generation being built on the edges or middle of the transmission system. This is increasingly being recognised as a problem, but quantifying the impact can be tricky.

Developers are asking: “What other generation will or can be built in the area? Will there or can there be collocated storage? When may these things be built? Will other projects in the area have a similar generation pattern to my plant?” And these questions are becoming harder to answer with the wave of renewables development.

Answering these questions

There’s no real substitute for analysis and an understanding of the degree of certainty required.

A simple example of adding generation in north-east New South Wales illustrates the point. Naturally, developers think first about competition: “Will added generation displace existing generation in NSW or generation on the interconnector? What is the most conservative assumption? What is the balance of probabilities?”

Even this simple example leads to many assumptions and choices, so proponents and owners need to understand how certain they need to be – and therefore how thorough the investigation of congestion needs to be.

What other questions are there?

Traditionally, congestion has been considered a problem of network thermal capacity. The nature of renewable energy generation adds other factors into this mix, such as: “Will fault levels remain high enough to support short-circuit ratios? Will critical clearance times be maintained to allow the full thermal capacity to be used? Will imbalance of generation development on parallel paths reduce pre-contingency loading limits?”

These sorts of questions require complex analysis, adding further uncertainty and additional dimensions to the results.

There’s talk of additional network provision being required to support changes to the flows in the transmission system. Such changes will no doubt be helpful, but questions of when, how much and who pays must be asked. 

We can see that calculation of congestion has real impact on expected revenues – but with so little certainty, it is hard to determine how critical any impacts may be on the overall business case.

What about losses?

The other effect of large generation on transmission flows is greater network losses. The marginal loss factor (MLF) regime that accounts for losses in the National Electricity Market (NEM) relies on many of the assumptions of congestion analysis, with similar levels of uncertainty of the input increasing the uncertainty of the output.

MLF has always appeared punitive for new renewable generation distant from the load centre, since long transmission distances (often over low-capacity lines) lead to inefficient power delivery.

The MLF regime is supposed to incentivise development of efficient and timely generation and demand. The drivers for renewable generation are less about actual demand and more about displacement, so the MLF inhibits the building of new generation in favour of the status quo.  A simplistic analysis, however, shows that, on average, new renewables see slightly higher MLFs than the established generation and new thermal assets.

There could be a number of explanations for this but it shows that the density of generation has remained low enough thus far. Increased build and in-fill will ultimately lead to MLFs becoming a bigger and bigger factor for new and existing plant.

Other congestion issues

There’s another form of congestion looming or already starting to impede the rapid deployment of solar and wind technology: a lack of capacity of network service providers (NSPs) and other regulators to deal with the influx of applications for new connections.

Add to this the increasingly technical analysis required to demonstrate compliance of these connections with the rules and a real bottleneck is created.

Blow your nose

The truth is, the only answer to any congestion issue is to remove the blockage .

In terms of network congestion, in the short-term, we need to continue to think about the likely requirement for renewable developments (with storage) to meet the challenges of the energy trilemma – replacing coal-fired generation following retirements with reliable, affordable and more sustainable generation.

And we will need to better understand the value of transmission re-enforcement to support a changing generation fleet.

It may also force a return to the Hub or Scale Efficient Network Extension (SENE) type of thinking that gives a clear signal to proponents to ‘build here’, as we can now see in New South Wales.

Network re-enforcement may also improve MLFs, slightly. However, if MLFs are low across the board in a region, the pool price will adjust to reflect this over time. In the short term, local or regional storage may be cost-effective in raising MLFs to investment-tolerable levels.

In terms of resource issues, training and applying more skilled resources to this sector must be a focus for NSPs and regulators.

Our approach as consultants is to not always recommend more analysis but, alternatively, the right and the most efficient form of analysis.

The challenge for NSPs and regulators is to act more commercially and embrace an engineering approach to analysis, tolerating some uncertainty – just as proponents do.

We always feel better once the fog of congestion lifts. Sometimes we try to fight through it, but it’s often better to take deliberate action to treat it and to avoid complications, just as when you are suffering the symptoms of a cold.

If you would like to find out more about how Entura can help you navigate network challenges, please contact Donald Vaughan on +61 3 6245 4279.

About the author

Donald Vaughan is Entura’s Technical Director, Power. He has more than 25 years of experience providing advice on regulatory and technical requirements for generators, substations and transmission systems. Donald specialises in the performance of power systems. His experience with generating units, governors and excitation systems provides a helpful perspective on how the physical electrical network behaves and how it can support the transition to a high renewables environment.

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Winning over your solar farm community

Effective engagement can reduce community opposition to a solar farm, but, better yet, it has the potential to create a level of community support that results in locals themselves promoting it.

Regardless of the technology, any large-scale renewable energy project will attract attention from its nearby communities. Without a ‘social licence’ to operate, the project may face significant hurdles including negative publicity, public protest, litigation or even cancellation of permits.

Engaging with the host community early in the development stages is key to a successful project and developers may be required to demonstrate that they have done so, even before submitting a permit application. This will help assure authorities (and potential buyers) that the project has support.

These are our top community engagement tips for developers to ‘keep the sun shining’ on a large-scale solar project.

Know your community

Despite the exponential rate of increase in large-scale solar installations in recent years, it is still a relatively new technology. While some community members may be quite knowledgeable about renewable energy technology, others may know little.

Each person will have different attitudes and expectations of a solar farm, and engagement should include all stakeholders in the community to make sure nobody is left out of the conversation. Someone living close to the solar farm may be interested in how it will affect the value of their property or if PV panels will reflect light in the direction of their home. A business owner in town may be interested in employment opportunities or how construction will affect local roads. An obvious question for everyone is whether the project will lead to cheaper electricity!

A developer, owner or operator should identify and meet as many different stakeholders in the community as possible to get to know their individual interests and needs.

Design a relevant engagement program

A comprehensive engagement program must communicate accurate project information, set realistic expectations, listen to the community, incorporate feedback into project design, and find opportunities for the solar farm to ‘give back’ to the community in some way.

Well-planned projects need engagement strategies designed specifically for the community in which the project is located. Using a ‘one-size-fits-all’ approach won’t cater for the unique circumstances of each community.

To inform the choice of engagement methodologies and tools, developers should consider the size, interests and skills of the local and regional community, the number of neighbours, who the local influencers are, and what other energy developments are present in the region.

Methods to engage with different stakeholder groups will vary depending on the stage of the solar farm’s development and the objective of the engagement process at that stage. Engagement practitioners use a range of different communication tools, from more traditional techniques to social media, from ‘kitchen table’ meetings to reference groups and focus groups.

Communicate realistic expectations

Large-scale solar farms are generally less controversial than wind farms or hydropower projects due to the relatively low physical impact they have on communities and the local environment. However, there may still be questions and concerns in the community, especially for communities in remote and rural locations where there may not be any other large infrastructure.

Throwing scientific facts and figures at people to convince them of benefits or mitigate fears will not necessarily help concerned locals feel any more confident about a project. Anecdotal negative information can be readily found on the internet to undermine confidence, and some community members may distrust the intentions of developers from large corporations.

The task of building the community’s confidence in a project is therefore an important yet sometimes difficult activity. The best approach is to communicate any foreseeable short-term and long-term impacts as early as possible and in an open and non-defensive manner before the community dwells on the risks. Listening to the community and working together to identify social and environmental risks will help build trust between the project team and stakeholders.

Build trust and confidence

Genuine community engagement is not ‘spin’. It’s about building an open and ongoing relationship with local stakeholders. The more work that is put into building healthy relationships and trust, the stronger the foundation for achieving a social licence to operate.

As communities generally become more familiar with large-scale solar technology, there will likely be a shift towards greater community acceptance of solar projects. Until then, developers need to recognise the community’s interest in a project and take responsibility for explaining solar technology and identifying risks for the community.

Local stakeholders should be told about a project prior to applying for permits. By engaging early, the developer will have time to explain how solar technology works, outline the construction process, and conduct a social risk assessment. Preferably engagement should be face-to-face and consistent. People are far more likely to accept projects when they feel that they have been included, heard and respected.

Obtain a ‘social licence’, but don’t stop there

Obtaining a social licence to operate is essential. It can mean the solar farm and its owner are talked about positively in the region and the project encounters few hurdles. But obtaining a social licence is not the end of the journey. A social licence must be maintained throughout the project’s lifecycle. 

Owners and operators can maintain a social licence through ongoing and regular communication with the local community and other key stakeholders. Communication should be two-way and communities should know how to easily provide feedback that is treated confidentially. Stakeholders should also trust that their concerns about the solar farm will be recorded and responded to in a timely manner. Evaluating and reporting on feedback will also help to promote a transparent and constructive process.

If you would like to find out more about how Entura can help you engage successfully with your solar farm project’s community, contact  Silke Schwartz on +61 407 886 872 or Patrick Pease.

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Dispatchable renewables: a contradiction in terms?

As Australia replaces retiring coal generation with renewables, can we achieve an energy future that is affordable and sustainable as well as reliable?

The role of renewable energy in achieving affordability and sustainability is clear. As coal-fired power stations approach retirement in Australia, renewable generation from wind and solar PV appear to be the most cost-effective options for new energy generation. Wind and solar power now offer the lowest cost of energy, have low ongoing operational costs, and emit the least greenhouse gases across their lifecycle – and therefore hold the greatest potential for rapid decarbonisation of the energy sector.

But what about achieving the third element in what has been termed the ‘energy trilemma’: reliability?

Replacing coal-fired power stations with wind and solar PV is not a like-for-like swap in terms of availability of power when it is needed by consumers. Coal-fired power stations produce firm baseload power, but generation from renewable resources varies due to the availability of the natural resource. Wind and solar PV power vary according to the weather and the time of day, and even if we consider new hydropower opportunities, most of these are small ‘run-of-river’ systems, the output of which varies with rainfall and the inflows to rivers.

Yes, these renewables certainly produce energy, but is the power produced when it is needed?

The variability in power from renewables makes matching supply and demand a challenge. This challenge increases as more renewables enter the market. With moderate amounts of renewables, it is still possible to maintain system reliability through clever solutions – in particular, targeted grid support designed through careful planning and study of generation profiles, and supported by solid communications, control, power systems studies and forecasting. However, there is a limit to such approaches, and ultimately Australia will need ‘dispatchable renewables’ in the energy mix to achieve all the elements of the energy trilemma – in other words, renewable generation that is available whenever consumers require it. The time to start planning for this transition is now.

For generation to be dispatchable it needs to be available at the request of power grid operators or the plant owner according to the needs of the market. Dispatchable generators can be turned on or off, or can adjust their power output according to market need. If a generator is dispatchable it can be used to match load, meet peak demands, or fill the gap if another generator suddenly goes offline. Dispatchable generation is very valuable to the market because it can be used to match the profile of energy demand.

Effectively, baseload fossil fuel generation can be replaced by the combination of variable renewables, dispatchable renewables, smart high-voltage network support and planning to ensure sufficient transmission capacity, and change in use of existing hydropower.

How can we make variable renewables ‘dispatchable’?

The concept of dispatchable renewables seems almost contradictory: how can something generated from an inherently variable resource be dispatchable? There are two parts to this: the first is to look at how well different wind and solar PV sites naturally work together to firm supply (i.e. how likely it is that dips in one source are filled by peaks in another). Once this is understood, we need to consider how much storage is required to manage residual variability. Storage is critical here as it provides flexibility to store excess or low-value energy for times when it is really in demand.

When patterns of renewable generation are highly correlated (in other words, the timing of generation is very similar), more storage is required. For example, if the east coast of Australia develops a very high proportion of solar PV generation capacity, then all of these will be generating within about two hours of each other during the day (because of similar sunrise and sunset times across this region), and not at night. To fully utilise this energy, much of it would need to be made ‘dispatchable’ by adding substantial storage for the night-time hours, or we would need to firm the supply using another generation source, such as a gas turbine. But with a suitable proportion of wind in the mix (and stronger interconnectors to solar generation from other regions), the same dispatchability can be achieved with a more moderate amount of storage. This example demonstrates the importance of achieving a mix of renewable generators to meet the goal of dispatchability. 

Various studies of generation in the NEM over time have demonstrated that wind and solar generation are not highly correlated. These studies have shown that even with low to moderate correlation, when considered over a large geographical area, a combination of such generators reduces variability and increases reliability of supply. Understanding this effect enables appropriate sizing of storage to create a dispatchable renewable portfolio with maximum value. There will always be some times when multiple generators produce near maximums, as well as some times when both wind and solar produce near minimums; these occasions are not common, but could have significant consequences. This is a risk that needs to be managed by the system.

The amount of firm capacity can be increased by over-installing generation, and curtailing its output when there is too much generation. However, there are still those infrequent periods when multiple generators are at their minimum and parts of the grid need extra support. Having this support available during these rare occasions will be critical to managing risk and maintaining reliable supply.

This indicates that the mixture of different renewables won’t take us all the way to the goal of achieving ‘dispatchable renewables’; storage remains a critical ingredient.

What’s the future for energy storage?

The media is awash with reports of new energy storage options. It is important to recognise, though, that different types of storage solutions vary widely in their ability to discharge power over different time frames. Therefore one type of storage will not necessarily deliver the same solution as another type of storage. Understanding this is critical to the concept of dispatchable renewables.

The power and duration of the storage are the two key variables in determining the most suitable solution. Low-power, short-term storage is currently more cost-effective using batteries, but longer periods and larger power requirements are likely to rely on bigger storage options, such as pumped hydro energy storage and traditional hydropower.

With individual wind and solar plants pushing 1 GW, pumped hydro and modified traditional hydropower solutions need to be considered. Smoothing out the daily variability in renewables can be achieved effectively through pumped hydro, but multi-day storage to supplement periods of extreme events of both low wind and low solar will require traditional hydropower with very large reservoirs.

In the long run, short-term storage will not be sufficient alone to achieve the aim of ‘dispatchable renewables’. Achieving full dispatchability of combined wind and solar PV power will depend on utilising pumped hydro storage and existing hydropower storages to their full potential.

When will we need dispatchable renewables?

The question of when we’ll need dispatchable renewables is complex. It’s driven by a combination of commercial, regulatory and technical considerations as well as changing customer behaviour (all of which are in motion).

The short answer is now.

There are already isolated opportunities in which dispatchable renewables offer distinct advantages, and where the business case may stack up. With increasing wind and solar PV developments in the network without dispatchable capability, such opportunities will only expand. However, the lead time required to include large-scale storage in these ‘dispatchable renewables’ projects means that planning must begin well in advance.    

If you would like to discuss how Entura can help you explore potential opportunities for dispatchable renewables, please contact Phillip Ellerton on +61 439 010 172, Richard Herweynen on +61 3 6245 4130 or Chris Blanksby on +61 408 536 625.

About the authors

Richard Herweynen is Entura’s Technical Director, Water. Richard has three decades of experience in dam and hydropower engineering, and has worked throughout the Indo-Pacific region on both dam and hydropower projects, covering all aspects including investigations, feasibility studies, detailed design, construction liaison, operation and maintenance and risk assessment for both new and existing projects. Richard has been part of a number of recent expert review panels for major water projects. He participated in the ANCOLD working group for concrete gravity dams and is the Chairman of the ICOLD technical committee on engineering activities in the planning process for water resources projects. Richard has won many engineering excellence and innovation awards (including Engineers Australia’s Professional Engineer of the Year 2012 – Tasmanian Division), and has published more than 30 technical papers on dam engineering.

Dr Chris Blanksby is a Specialist Renewable Energy Engineer at Entura, and Entura’s lead solar energy specialist. He has undertaken and published research on the solar resource in Australia, and has led several due diligence and owner’s engineer projects for wind, solar and microgrid projects in Australia, the Pacific and Asia.  

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Six steps to reduce risks when investing in renewable energy projects

Big investments require confidence – however, caution in unlocking funds is perfectly reasonable. A thorough due diligence is the key to building investment confidence by identifying and quantifying the project’s risks, costs and benefits. 

Due diligence is a broad term, and consists of technical, legal and commercial considerations. In practice, it means developing a full understanding of the proposed project, discovering any risks that could prevent its success, and capitalising on the project’s strengths. Not all risks will be ‘show stoppers’, but identifying any potential risks, judging the likelihood and impact of those risks, and identifying mitigations will enable greater confidence that the project is a viable investment.

Whatever the renewable energy project – a solar farm, wind farm, hydro scheme, hybrid solution, pumped hydro energy storage facility or other emerging option – technical due diligence considerations need to explore total energy yield, project uncertainties, technology choices, social and environmental implications, contractual terms, the business case and also non-financial goals.

1 – QUANTIFY ENERGY YIELD AND UNCERTAINTIES

For any project, a critical requirement of lenders is a bankable energy yield assessment. Renewable resources such as sunlight and wind generate power with a variable output that can be forecast, but is not necessarily available on demand. This leads to daily, quarterly and annual variations in generation and to uncertainties in revenue that need to be factored in. Despite this variable yield, renewable projects do not incur the risks of variable fuel costs which affect other energy projects.

To avoid lower-than-expected revenue generation, the project needs to be able to export power into the electricity grid without constraint. This makes the grid connection arrangements and understanding the risks associated with the eventual operational regime critical to the success or failure of a project.

2 – JUSTIFY TECHNOLOGY CHOICES

Project lenders require confidence in the capability and reliability of the proposed technology for the project. For wind farms and hydropower projects using equipment from a supplier with a long operational history or large install base, this is less likely to pose hurdles than for emerging renewable energy options such as hybrid systems using batteries.

A project developer would be well advised to obtain relevant documentation from suppliers, such as a solar panel’s assessments results from recognised testing institutes. Absence of information is likely to result in conservative assumptions for financing purposes, so efforts to extract and justify all parameters is typically well worthwhile.

3 – ENSURE SOCIAL ACCEPTANCE AND ENVIRONMENTAL REPUTATION

Renewable energy projects operate within communities. There will be a range of attitudes towards any project and many stakeholder relationships to manage. The relationship established with the project’s community can make a substantial difference to the success of the project.

A major risk to social acceptance of the project and development approvals is environmental impacts. Best-practice identification, mitigation and management of the environmental implications of the project is critical to the long-term success of a project and to corporate reputation.

4 – TAKE CARE WITH Contracts

Renewable energy projects require a large upfront capital expenditure. Depending on the investor’s risk appetite, exposure to risk can be managed through the contractual arrangements with the developer, equipment suppliers and the construction contractor.

Land-owner agreements; connection applications; engineering, procurement and construction contracts; supply and installation contracts; and operations and maintenance contracts of various forms will be required to develop, construct and operate the project. While a legal adviser will need to comb through these, many technical aspects can vary significantly in their favourability to a purchaser or investor. Identifying and quantifying these items will need input from a technical advisor.

Investments that are otherwise sound can suffer due to delays in construction, which can have significant impacts on expenditure and revenue profiles, and the terms of any debt provision. The investor can mitigate some risk through delay damages in EPC contracts, however, the adverse impacts of projects delays are rarely fully mitigated by contractual arrangements.   

For operations and maintenance, comprehensive long-term agreements offered by the original equipment manufacturer are an effective method of transferring risk associated with plant reliability onto the supplier or EPC contractor. However, the certainty afforded will come with a cost premium, and it is critical to appreciate that a comprehensive operations and maintenance agreement does not guarantee energy output.

5 – UNDERSTAND MARKETS, POLICIES AND REGULATION

Renewable energy projects are often supported by government policies that recognise the environmental benefits of clean energy generation. It is essential to understand both the commercial market for the energy and the policy environment in order to negotiate power purchase agreements or to manage merchant risk if the energy is being sold on the spot market.

It is also vital to understand the relevant regulatory frameworks – planning, environmental, electricity grid, corporate governance, taxation, financial, employment, or occupational health and safety. All these factors need to be considered when assessing the cost of the project and the risks associated with the investment.

Another potential risk – or opportunity – is change in the market, both short term and longer term. Consider how foreseeable or unforeseeable market movements (such as changes in industrial loads, or shifting levels or patterns of demand) may affect performance and viability of the project over its life.

6 – ASSESS THE BUSINESS CASE AND OTHER GOALS

The ultimate motivations and goals of the investor will influence the assessment of risk. The project may not simply be all about financial return, but also a desire to limit carbon exposure or to increase corporate social responsibility. Understanding the goals of the project will provide a clearer perspective for the due diligence investigation.

Whatever the motivations of the investor, the financial realities of the business case will be critical. Technical viability and environmental benefits won’t be enough to get projects over the line if they can’t demonstrate their long-term financial soundness and ability to weather the competitive pressures of the market.

Businesses are likely to gain substantial benefits from making structured and systematic efforts to foresee and quantify risks across the spectrum of commercial, technical, social and environmental issues. The more detailed a due diligence process is, the more accurately risks can be quantified, and the less likely it is that potential risks will be overlooked. A thorough due diligence will take time and expertise, but it is a critical investment in the success and resilience of every renewable energy development.

To discuss how Entura can assist you with practical, expert technical due diligence services for proposed or operational projects in Australia and the Asia-Pacific region, please contact Patrick Pease, Silke Schwartz on +61 407 886 872 or Shekhar Prince on +61 412 402 110.

About the author

Daniel Bennett is a renewable engineer at Entura. He has near a decade of experience investigating feasibility and due diligence energy yield assessments for renewable projects in Australia and around the world. He has worked on various wind farm projects in Australia, China, India, Sri Lanka and South Africa. Daniel has also worked directly for developers and suppliers.

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Maximising the benefits of GIS for better business decisions

‘Location, location, location!’ It’s a familiar catch-phrase in the real estate industry, but it’s just as relevant in the power and water sector. Wherever there’s location-related data, a geographic information system will guide better business decisions.

Mobile devices and apps are increasingly using location-based data collected via satellites, drones, LIDAR and other rapidly developing sensing and data capture technologies. With these advances, we are able to find relevant information more quickly and draw on that information to make informed decisions. We’re seeing this proliferate in everyday life through apps that help us navigate, find services and products, and make decisions ranging from the trivial to the profound.

Developers and managers of power and water infrastructure projects who embrace GIS (geographic information systems) stand to gain benefits on an even greater scale. Gathering high-quality spatial information and analysing it to guide business decisions will certainly improve productivity and the bottom line.

Better decisions are the necessary foundation for increased revenue, lower costs, greater efficiency and productivity, and reduced risks. So, if the technology is available and there’s so much to gain, why isn’t GIS being as widely used in the power and water sector as it could be? What may be holding businesses back from fully embracing this powerful and dynamic technology?

Do we really need to use GIS for this project?

All power and water projects involve location – from finding an optimum site for your project, to analysing combinations of spatial data to make the best management decisions or to predict events. Whenever you ask a ‘where?’ question, GIS can help. Where is the asset best located? Where are the constraints or hazards? Where are the reports of previous work done in this area? Where are the customers or opportunities?

In other words, rather than asking whether GIS is needed on a project, consider making GIS a default for every project. The real question should be “how can we maximise the benefits of using spatial data and GIS on this project?” GIS can offer business benefits far beyond the most commonly understood use: making a map.

Data capture in the field can now be streamlined – gone are the days of capturing field data with pen and paper. Users can now collect data on mobile devices, sync to databases while in the field, share data, and generate their own maps, queries and reports. Embracing these advances will save time and enable faster and better decisions.

As well as providing valuable business insights, spatial analysis and location intelligence can greatly improve communication and knowledge sharing – within project teams, with the broader business, and with the community and stakeholders – via tools such as web maps and apps, visual analysis and 3D modelling.

One of the most important applications is the simultaneous analysis of different spatial datasets to provide the best solutions or choices between alternative options, locations, objects and so on. This process is better known as multi-criteria analysis (MCA) and it can be used for many applications.

For example, MCA can be used to find the optimum site for your project taking into account a range of values such as local geology, threatened species, resource availability, land use and terrain, planning restrictions, communities and demographics. Using MCA, you can establish areas of best fit for your project based on thematic overviews of areas of constraint, cost of construction, access and transportation routes.

Risks such as bushfire, weeds, threatened species, pollution sources, landslides and erosion can also be more easily and fully understood, supporting your ongoing site management of such issues.

GIS also links with document management, asset management, business intelligence and enterprise resource planning (ERP) systems. It can act as a portal, creating a central point of easy access, pulling together information and making it available on one of the simplest forms to interpret – a map.

Of course GIS is not the answer to everything, and it is not a standalone platform. However, there’s much it can offer across many different business activities, working together with other business systems.

What about the costs?

The return on investment of using GIS should be positive if it is used appropriately. For site selection of power and water projects, using GIS is a no-brainer. For example, using GIS to find the best site for a wind farm – locating the best winds, minimal constraints, good proximity to existing infrastructure and appropriate land use – will obviously result in vastly greater returns than siting the wind farm in an inferior location.

Some examples may be less immediately apparent, but equally valuable – for example, using GIS to increase efficiencies in everyday workflows. If your workers are taking an extra half hour every time they need to find previous work completed in an area, this time can add up quickly. Or perhaps they can’t find previous information, so work is re-done unnecessarily. These costs will keep adding up. Instead you could use a GIS web map to locate all your previous reports and projects, so that a simple click on a map finds the files and saves hours (if not days) of time.

Do we need specialist software or skillsets?

With most things, you do need specialised skillsets and software to get good results, and of course bad data in equals bad data out. Users of GIS do need to understand and assess the spatial data needs in each application.

You could undertake some GIS work yourself using free or open-source software. However, be aware of the risks of using data or tools that aren’t fit for purpose. Just because you know how to use Microsoft Word, doesn’t mean you could write a detailed report outside your area of expertise!

We have seen cases where coarse-resolution data has been used to infer finer project details and costs, resulting in poor decisions. We have also seen inexperienced operators make invalid assumptions. To get the best results, you need to be sure that you’re using the technology wisely.

If you are engaging a power, water or environmental consultant on a project, they are likely to have access to GIS capability; however, GIS is still often underutilised. When deciding who to engage on your project, ask your consultant how they will maximise the benefits of GIS to produce better outcomes for your project.

To discuss how Entura can help you harness the potential of GIS to improve your power and water project decisions and outcomes, contact Stephen Thomas on +61 3 6245 4511, Patrick Pease or  Phillip Ellerton on +61 439 010 172.

About the authors

Stephen Thomas is Team Leader and Senior Technical Officer with Entura, specialising in geographic information systems, 3D visualisation and CAD software. Steve has over twenty-six years of technical experience and specialises in environmental assessments and approvals for engineering surveys and property. He has created 3D models and animations of proposed developments including wind farms, urban landscapes and city frameworks. Steve’s work on the Hobart Waterfront 3D model won an international award in geospatial modelling.

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The foundations of successful large-scale solar farms

On any large-scale renewable energy project, every opportunity to reduce costs counts.

Utility-scale solar farm projects require significant investment. So to keep total project costs under control and ensure success, it is vital that every step in design, construction and operation explores the most economical ways to create an efficient and safe project for the long term.

Although the civil engineering components of site development for a large-scale solar project may be smaller than the structural or electrical packages, civil costs during construction could add up to 8-10% of the total project cost – and that’s nothing to sneeze at.

Upfront consideration of costs and risks – both short-term and long-term – in the civil design of the plant can make a sizeable difference to the project’s total cost of construction, cost of long-term maintenance, and long-term financial returns.

Achieving the best and most economical civil works design means thinking carefully about the specific conditions of the site and the expected operating conditions of the project over 25 to 30 years, taking into account the potential for these conditions to change over time.

Getting the foundations right

Utility-scale solar farms need ground mounting systems and layout that suit the specific topography and geology of the site. Identifying the optimum solution in these areas is a key part of achieving a cost-effective design.

The mounting system functions as a foundation structure, and can also set the orientation and elevation of the PV arrays to maximise energy performance. Orientation, tilt and elevation need to be addressed in the civil design, for example to work out the PV panels’ ground clearance or likelihood of collision. As PV panels are lightweight structures, design of a stable foundation must also attend to vertical uplift and lateral resistance, in accordance with the relevant standards.

The various brands of tracking systems all compete to provide cost-effective solutions, particularly to address the challenges of undulating sites – so research the range of options to find the best fit for your project.

The challenges of undulating sites.

A lack of proper geotechnical ground investigation can lead to selection of inadequate foundation types, resulting in costly variations and delays. On-site pull tests will help support and augment the recommendations of the geotechnical study to optimise selection of a cost-effective foundation solution.

Installations that follow the topography are likely to allow a reduction in earthworks (cut/fill) and allow easier and more consistent choice of pier height and length per row. Shorter rows can follow the terrain better than long rows, but this is not the only criteria for selection. You should also consider aspects such as cost of cable management, extra motors and installation time. 

The height/length, material and foundation options for piers become very significant when dealing with thousands of piers per solar farm. This means that you need adequate representation and quality assurance for design outputs. 

Each individual pier height should be determined from detailed topographic surveys and computer modelling, taking into account the different minimum heights required to avoid ground collision, and the maximum heights that will be most economical for long-term operational and maintenance.

Another consideration in the search for cost savings is balancing the distribution of piers against the cost of earthworks, which will vary depending on the depth of cut and fill required.

There are a number of different foundation options, such as driven steel piers, screw piers, and precast concrete footings. But determining the appropriate choice must be based on a comprehensive understanding of the geology and geotechnical model of the entire site – which may vary across the large area of land occupied by the solar farm.

Rocky sites may result in driven piers reaching premature refusal. Sandy sites will vary in cementation and looseness, influencing any attempt to have a constant pier ground embedment. And clayey sites are prone to shrink-swell changes depending on changes in the level of moisture due to flooding or drought. 

Planning for a changing future

For prudent design, you need to consider how the site conditions could change over the whole life of the solar farm, as early pull tests won’t predict future conditions.  For example, how could the site be affected by flooding or by erosion – both now and under future climate conditions?

Thorough stormwater assessments (hydrological and hydraulic) are required to develop a good understanding of the existing (before development) and proposed (after development) drainage patterns of the site. If the site development alters the pre-development conditions, sediment control measures will need to be put in place.

The stormwater modelling will help to quantify the extent of flooding and potential for erosion. 

For flat sites, allow for inundation (with major impacts on construction and potential deterioration of the site, trenches and foundations); for undulating sites, expect flash flooding and potential erosion and transfer of sediment.

Floodwater heights might affect solar farm infrastructure such as tracker motors or combiner boxes, so these will need to be installed at safe heights to minimise major potential repair or replacement costs. 

Stormwater assessments will also quantify erosion potential around foundations, so that you can put suitable control measures in place, such as allowing for internal and external discharge points and armouring erosion-prone areas with riprap or erosion protection geotextiles.

Beyond the solar array

A number of other factors need to be considered in the civil works package, all of which have potential for efficiencies to reduce cost and avoid delays.

Roading alignments (horizontal and vertical) must consider the different needs of the construction phase and the longer-term operational period.  Design of earthworks and road surface should take account of potential impacts on drainage patterns and potential erosion at low points.

Cable trenching should address interfaces and collisions with other infrastructure, and the need for backfill to meet requirements for thermal resistivity and strength.

Fencing is required for adequate site security specifically during operational life, but must be considered along with the need for access at various stages of the project. Fencing insulation and earthing needs must also be assessed in the design.

Civil design will also address the requirements of hardstand and laydown areas, particularly for the demanding construction phase.

Designing the risks out of your project

Based on our experience, we recommend that the civil design of a utility-scale solar farm should go through three phases: concept design, optimisation, and detailed design. If you rush from the concept design phase into detailed design, you’re opening your project to risks.

Significant optimisation will then be needed during the detailed design phase, which could potentially alter the concept design. That means rework, costing you time and money.

To achieve a civil design that avoids project risk and sets the right conditions for cost-effective delivery, be sure that you have timely, accurate and comprehensive topographic and geotechnical data about the site, that you carefully consider your earthworks material and handling, and that your systems and equipment interface all infrastructure effectively.

Keeping construction budgets under control and schedules on track depends on all the careful, detailed work done across all the aspects of the project at the design stages. Get your civil works right, and you’re tilting your solar farm towards success, whatever the weather.

To find out more about how you can ensure a cost-effective civil design for your solar project, contact Al Ahmed-Zeki on +613 6245 4122, Patrick Pease or Silke Schwartz on +61 407 886 872.

About the author

Al Ahmed-Zeki is a Specialist Civil Engineer with more than 30 years of civil engineering experience on renewable energy assets, including dams, solar farms and wind farms. He had led the civil design for a number of major solar projects from pre-bidding assessments through to due diligence and detailed design. Risk management is one of his prime interests. Al has published a number of technical papers and presented in the fields of geotechnics and dams engineering.

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Protecting your embedded generator from islanding without breaking the bank

If you are planning to generate some of your own electricity, such as through a few wind turbines or a small solar farm, you’ll need to know about islanding.

Adding new embedded generation such as wind or solar into the power grid can produce some challenges, but these challenges can be overcome. One such concern is the potential for network faults to cause islanding – in other words, when an embedded generator keeps supplying power to a grid when the grid power falls or fails, forming an island.

Understanding the cost implications of anti-islanding protection will help you negotiate with your network service provider, and may help you save money on a fit-for-purpose solution.

Network service providers (NSPs) are particularly sensitive to the risk of islanding. Although the probability of an island developing is low, the potential for islanding causes NSPs concerns about safety, about delivery of poor-quality electricity, and about the chance of damage to their equipment.

However, the high costs of some anti-islanding measures could cripple your embedded generation project, so you need to be aware of your options.

How can islanding be detected?

To protect against islanding, many NSPs will install high-speed communications circuits between your new plant and their substation or control centre. This works well: the NSP determines that an island may be forming and sends a trip signal to your generator. However, the communications circuit is expensive and, typically, the cost will come out of your pocket. The extra expense might spell the end for your power project, regardless of its size.

In the future, the gold standard in anti-islanding protection is likely to be based on synchrophasors, so that the phase angle of various parts of the grid can be compared and a tripping decision can be made without involving the NSP control centre. This method will still require high-speed communications circuits.

It is common for proponents to consider ‘passive’ anti-islanding protection based on measurements made at the generator. The usual measurements made to detect islanding are over/under voltage, over/under frequency, rate of change of frequency, and vector shift. The NSP is likely to ask what will happen if the island load matches the island generation. In a purely academic sense, if the load matches the generation then none of these elements will detect the island. But is this concern warranted in practice?

The bigger risk you will face, particularly in off-grid networks, is that the rate of change of frequency or the vector shift will trip your generator unnecessarily. It is very difficult to set vector shift protection sensitively enough that it will detect an island but not malfunction during a network fault.

What’s the best option?

If you are connecting an inverter-based system (e.g. a solar farm or a type 4 wind turbine) make sure that it has ‘active’ anti-islanding protection and that the inverter documentation discloses the method being used. In Australia, simply specifying compliance with the standard AS 4777 is sufficient.

Specialist advice on how the active anti-islanding protection operates will help you and your NSP determine whether you can avoid the need for high-speed communications and use a lower cost communications circuit such as 3G.

If you are connecting an induction generator, you might think that it is not possible to supply an islanded load. It is not impossible, just unlikely. Your NSP may not accept unlikely, when you could install a high-speed communication circuit and eliminate the risk at no additional expense to them.

Although an induction generator can sometimes supply an islanded load, it is almost impossible for it to do that at nominal voltage and frequency. Passive protections can be applied and are likely to work reliably. The rate of change of frequency protection is particularly useful in this case because, unlike vector shift, it is not susceptible to network faults as long as you select a relay with the right algorithm.

If you are connecting a synchronous machine, you’re providing valued inertia, but you may have the largest anti-islanding challenge. The synchronous generator can supply an island indefinitely and often without going far outside the nominal system voltage and frequency.

In this situation, there are three alternatives:

• You could attempt to convince your NSP that the power you provide to any island will be of the highest quality and that there is no need to panic if an island is created for a short time. The NSP will likely ask you to fund the installation of one or more new voltage transformers in their network.
• You could accept that high-speed communications really are required to safely incorporate your new generator into the network, and shoulder the expense.
• You could apply vector shift protection to your generator and accept that there will be occasional instances in which your machine will trip off and need to be restarted following a network fault.

Anti-islanding protection is complex, and it adds an extra hurdle in the process of embedding small generators in our networks, but this challenge can be resolved satisfactorily. By being better aware of your options, you’ll be much more likely to achieve a safe and cost-effective solution that meets your needs as well as the requirements of your NSP.

If you would like to find out more about how Entura can help you overcome islanding and other electrical challenges, please contact  David Wilkey on +61 3 6828 9749 or Patrick Pease.

About the author

David Wilkey is Entura’s Principal Consultant, Secondary Electrical Engineering. He has more than 20 years of consulting experience in electrical engineering across Australia and New Zealand, focusing on the delivery of advisory on secondary systems and power systems engineering. David’s expertise spans all areas of electrical engineering with a particular focus on electrical protection, power system studies and rotating electrical machines.

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Following the money: financing your solar farm

The potential for successful large-scale solar in Australia is enormous, but problems with financing can spell death for your project.

In this final part of our series of articles on overcoming potential roadblocks to solar developments, we take a closer look at some key risks often scrutinised by lenders and investors for utility-scale solar PV projects.

Energy yield

It is important to engage a third-party consultant to carry out a bankable energy yield assessment for your solar PV project. This is required by project lenders, but is also useful for internal purposes, and for any future discussions with all the project stakeholders.  

To begin with, it is critical that the solar resource data appropriately represents the project site. An on-site measurement campaign using high-quality instruments for at least 12 months is recommended to capture the complete seasonal pattern, which can then be correlated with a long-term data set. If such on-site measurement is not available, using and cross-checking several high-quality satellite data sets from reputable data suppliers can be acceptable, though will increase risk and uncertainty.

Energy modelling needs to be in line with the actual design of the project. Make sure that the equipment input files for the modelling software are properly checked and supported by actual data. Transparency in these inputs means increased certainty in the energy yield results.  

Degradation of PV modules is a contentious subject, and of concern to lenders and investors. For solar PV projects financed in Australia, the degradation assumptions (in the system level) are in the range of 0.5% to 1%, which is supported by a body of recognised studies. Lenders may request supporting information to justify lower-end degradation numbers.

In addition to total energy yield, the generation profile over the year is increasingly important in estimating revenue and securing power purchase agreements, and thus needs to be estimated accurately. Combining your solar PV plant with battery storage can offer further unique advantages to optimise revenue and minimise connection costs. However, battery storage adds another layer of analysis to estimate the final generation profile and the additional energy losses based on the specific battery technology and control strategy.

Uncertainties

Uncertainty analysis is a crucial element of any bankable energy yield assessment as lenders and investors need to look at the project’s downside energy production scenarios at different time scales. It is not uncommon for banks to finance a renewable project using a conservative scenario.

The uncertainty of the energy yield assessment may dictate the debt sizing, or influence credit ratings for the project, so it is critical to fully understand the project’s resource uncertainties.

The main uncertainty that opens up downside energy production scenarios is the solar resource. A rigorous resource assessment is likely to considerably improve the financing conditions for your project. Other inputs and parameters used in the analysis can also introduce uncertainty and must be well supported and justifiable, rather than pragmatically assumed.

Offtake Agreements

Offtake risk is another key element considered by financiers. Projects without power purchase agreements (PPAs) may struggle to obtain project finance or receive unfavourable financing terms. Only enter into PPAs with creditworthy counterparties with investment grade ratings.

Lenders ideally want PPAs with at least the same duration as the loan tenor, e.g. 15 years.

Entering into long-term PPAs directly with corporate offtakers is increasingly popular globally as large companies convert to 100% renewables. Although not common in the Australian market, corporate PPAs do offer an attractive solution for future renewable projects in effectively mitigating offtake risk.

Technology

To date, few large-scale solar PV plants are operating in Australia. It is possible that your project will be proposed with PV module products yet to achieve a track record for utility-scale solar farms, so how can you offer project lenders confidence in the capability and reliability of the proposed technology?

Engage in conversations with module suppliers early and ask for relevant documentation, such as third-party bankability assessments and accelerated test results with recognised solar PV testing institutes. Absence of information must result in conservative assumptions for financing purposes, so efforts to extract and justify all parameters is typically well worthwhile.

It is also important to know, and to contractually specify, the specific bill of materials intended to be used by the module manufacturer, as different materials can vary performance.

Contractual terms

A good construction and maintenance contract can help you obtain favourable financing terms. For example, it is important to ensure that your EPC contract has well-defined principal’s requirements and technical specifications, with no exclusions in the scope of works or technical specifications that could result in significant cost variations incurred by the owner. Also, be sure that the operations and maintenance (O&M) scope is sufficiently thorough and aligned with the energy yield estimate, and be sure to budget for any out-of-scope O&M task particularly in regards to inverter maintenance.

Set out a rigorous yet reasonable testing scheme for final completion to ensure the quality and capability of the PV plant to deliver the estimated energy output. It is also advised that the guaranteed plant performance is in line with the energy yield assessment. A good contract also properly addresses the multi-year energy guarantee regime and associated liquidated damages scheme to good industry practice.

From a lender’s perspective, ideally you would want an O&M agreement with a contract duration to at least match the loan tenor, and with an all-inclusive thoroughly specified scope of services covering both preventative and corrective maintenance. This should ensure minimal out-of-scope O&M costs for the owner. A maintenance reserve account is typically required by the lender to manage any cost items not covered by the existing O&M agreement during the loan tenor (e.g. inverter refurbishment/repair/replacement).

Alternative Financing Solutions

The investment landscape is changing, and traditional project finance may not always be your best option. For example, for relatively small solar PV projects, project finance is often not cost-effective and transaction costs can be significant.

Green Bonds offer another solution for financing or refinancing of renewable energy projects. Green Bonds are any type of bond instrument used to finance or refinance eligible ‘Green Projects’. As the size of the global bond market is US$ 100 trillion, tapping into such a pool of funds will undoubtedly help to drive the renewable finance landscape in Australia. However, the Green Bond market is not accessible to all developers – and will typically require a significant transaction size (typically US$100 million or more), and specialised expertise.  

For smaller developers and projects, depending on the size, solar PV projects may be aggregated and funded on balance sheet, for example via a corporate facility, or with pure equity. Technical due diligence for projects financed in this way would still be required (particularly if planning to sell the projects once operational), and the overall key risk elements would be the same as for traditional project finance, although the scope of works required for due diligence may be reduced. Standardisation across smaller projects – for example, in configuration, energy yield analysis, equipment and contractor selection, and key contracts – is crucial for keeping transaction costs down in smaller projects.

When you can offer an investor confidence that your project has adequately considered and planned for all potential risks, achieving favourable and secure finance doesn’t have to be a roadblock to solar success.

If you would like to find out more about how Entura can help you overcome financing hurdles for your solar development, contact   Silke Schwartz on +61 407 886 872 or Patrick Pease.

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Connecting renewables in a changing grid

As the network continues to incorporate increasing levels of inverter-based asynchronous generation such as wind and solar, connection standards in the weakening grid are tighter than ever before.

Successful grid connection is a key factor in the ability of generating plant to operate effectively and reliably , and it does not need to be a roadblock to the roll-out of new renewable generation. But connecting new solar and wind generation into a weakening transmission system can involve challenging grid connection requirements, particularly at periods of low demand.

Network faults can cause potential imbalances between network segments, and these imbalances may be exacerbated by fault ride-through (FRT) algorithms.

We have written previously that it may not be easy to understand the worst case from a system fault perspective. So we need to consider a wide range of system scenarios in combination with a broad spectrum of contingency events. 

A number of factors are at play here, but we will focus particularly on the effect of FRT algorithms on the transient stability of the network.

When considering the connection, we tend to focus first on the stability at the connection point. This can lead to reducing the aggressiveness of the FRT algorithm to ensure FRT re-strikes are not caused by the power ramping back too quickly.

But this is where the seeds of the problem are sown. The weak voltage support at the point of connection leads us to withhold power longer during FRT to give voltage controls (remote or local) a chance to work immediately after fault clearance. In a stronger grid (even if we’re on a weak connection) this power deficit is not significant, but it can be crippling in a weak grid.

A fault forms two islands (momentarily). These two islands will invariably be unbalanced internally. That is, there will be a surplus of generation in one island and a surplus of load in the other. One island will then speed up and the other will slow down. If our inverter-based generator is in the island that is slowing down, then the withdrawal of energy by FRT makes the energy deficit in that island worse.

When the fault clears, the two islands need to re-establish synchronism. If the two islands have diverged then they may not be able to snap back to synchronism. This may lead to system separation and possible load shedding or worse.

What can be done when this occurs?

If a new connection runs into this problem as part of the connection studies, it may be able to get around it by tweaking the FRT controls. Setting these to return to normal control as fast as possible and to minimise the depth of power withdrawal during FRT will weaken the effect. Installing synchronous condensors may be another way to improve Short Circuit Ratio (SCR) at the connection point. This should allow more aggressive return from FRT.

On a network level, stronger interconnection and meshing should reduce the locations where faults can actually form the islands we’ve described here. This solution is possibly expensive, but network capability is currently the missing link in our Rules.

This is the problem we face as we move closer to the edge of the technical envelope. The capability of the network is not and has never been defined by the transmission elements alone. We’ve had generating units that have provided voltage and frequency stability. Now, those generating units are being displaced by wind and solar sources that do not provide the same levels of grid support.

This is where the interpretation of the Rules is going to be a threat to further renewable penetration. When assessing a new connection we routinely look for dispatch scenarios that will test the limits of grid strength. If the new connection can’t meet an appropriate standard of performance, we determine that it is this new connection that is at fault. Sometimes this is true, but sometimes it’s just that connections that came before have soaked up the available system strength.

On one level, this is an appropriate response. The new connection should not be allowed to connect if it can’t meet an acceptable negotiated level below the automatic access standard. On the other hand, it seems that the network resource is not being equitably shared. That is, people ahead in the queue have been given more than what we now understand to be a fair share. 

We’re not suggesting a reallocation of those shares. That’s impractical. Nor are we suggesting that earlier connection agreements were ill-advised. We, as an industry, just know more now about how valuable and scarce network strength can be. 

How will this affect future connections?

Ultimately we need a reasonable approach to negotiated access standards. Perhaps there’s a need for an adjustment to minimum access standards too. It is not practical or fair to expect that that burden be shouldered by new connections alone. Nor is it practical or fair to renegotiate the connection standards of existing plants. If we are to continue to add non-synchronous generation, we will need alternative sources of grid strength. 

If you would like to find out more about how Entura can help you overcome grid connection challenges when developing your solar farm, please contact Donald Vaughan on +61 3 6245 4279 or Ranjith Perera on +61 3 6245 4272.

About the authors

Donald Vaughan is Entura’s Technical Director, Power. He has more than 25 years of experience providing advice on regulatory and technical requirements for generators, substations and transmission systems. Donald specialises in the performance of power systems. His experience with generating units, governors and excitation systems provides a helpful perspective on how the physical electrical network behaves and how it can support the transition to a high renewables environment.

Ranjith Perera is a Specialist Power Systems Engineer at Entura. He has over 22 years of experience in Australia and South-East Asia, working on customer and generation connections and broader power system analysis.  Ranjith has provided power system advice on a wide range of network augmentations, network planning and system stability in Australia and internationally. These studies included option analysis in transmission planning, constraint analysis, determination of reactive support (dynamic or static) in system stability / TOV and detail load modelling in voltage stability. Ranjith also developed voltage recovery guidelines to TNSP based on regulatory requirement and customer equipment tolerances.

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Six essentials for solar farm design

Is designing a solar farm child’s play… a simple matter of snapping some Lego together? Not if you’re after maximum efficiency, operability and value.

Because solar builds are modular and repetitive, there is a temptation to take a ‘Lego approach’. This is appropriate once designers have convinced themselves that the Lego bricks themselves are fully optimised and fit for purpose.

Smart, site-specific design not only gets the ‘bricks’ right, but also aims for efficiency in all aspects and fully considers technology and standards, reliability and robustness, safety, layout, civil and structural issues, and the project lifecycle. This creates benefits that multiply across the whole project and through time.

1 – Technology and standards

Fit for purpose means, in part, meeting standards. While solar standards are evolving fast and the requirements for grid connection are tightening, future-proofing with inverter technology with high-end capability seems to make sense.

AS4777 is the main standard specifically addressing inverter energy systems in Australia. It has recently been revised and includes some significant changes to inverter requirements. Formally, it only applies to small inverters/systems, but the capability requirements act as a useful surrogate standard for larger equipment.

All inverters must still, of course, comply with all the legislated electrical and fire safety, access, and environmental requirements, so if choosing an inverter for which these requirements have not been demonstrated, make sure you allow time and budget for the compliance process.

Nevertheless, inverter technology is developing quickly, and many capabilities built into inverters go well beyond the requirements of the standards. These can add value to your project by reducing downtime or potentially enabling additional revenue streams such as grid support.

In Australia, the National Electricity Rules (NER) specify the performance requirements for inverters in schedule 5. As we noted in a previous article <link to the art of solar grid connection>, choosing inverters at the higher end of functionality and enabling that functionality will help avoid niggling performance issues and constraints across the life of the plant.

Life-cycle thinking should also flow through to other internal farm considerations such as the value that trackers may add or the type and arrangement of PV cells relative to the inverters and the DC collector system. 

For small to medium-scale systems (1–6 MW) you may wish to investigate if either string inverter or centralised inverter concepts offer the best value and operational flexibility.

2 – Reliability and robustness

Production is king. Every sunny day on which PV cell strings, inverters or cables are disconnected due to faults represents potentially avoidable lost production and revenue.

Design can help to minimise these sorts of outages in four main ways:  

Cell layout: Diffuse and direct shadowing can limit the effectiveness of energy capture across the farm. This is particularly challenging where the farm is south of the Tropic and the angle of the sun varies across the year. Minimising the effects of the natural and built environment and the near shading of on-site structures should be considered to ensure high cell utilisation throughout the year.

Redundancy and switching: Consider eliminating common points of failure where the cost of doing so remains feasible. This could include designing for only partial failure. The modular nature of the solar farm may naturally exhibit this feature but it is worth exploring whether the redundancy cannot be extended to single points of failure like transformers and switchgear. Switchgear should be employed to allow sufficient isolation as well as protection.

Monitoring: The speed of response to equipment failure can significantly reduce the impact on production. Capital spent on data links to remote inverters can provide helpful feedback on where faults have occurred and how to manage them even before technicians arrive on site. Monitoring may also provide some value in showing efficiency degradation due to dust or grime on PV cells without potentially costly over-cleaning or observation routines.

Contingency planning: The design should be conscious of the need (where there is value) to quickly replace faulty equipment without exacerbating lost production. Providing sufficient switches and cable junction boxes for safe and quick replacement of medium-voltage AC equipment or low-voltage DC equipment will assist operators to respond faster to outages.

3 – Safety of the public and personnel

Designing for safety of construction and operation and for the safety of the public are important legal requirements.

Ensuring easy access for constructing and maintaining the electrical infrastructure and managing the land will not only enhance the safety of personnel but decrease the costs associated with working on the site. Providing lighting or hard stands for lighting equipment may also allow safe maintenance and night works.

4 – Layout

If you have a rectangular, level, north-facing space, you are fortunate. This opens up the full spectrum of layout options and it is likely that trackers may feature in the design.

However, for every other situation, there is a complex geometric trade-off between practical considerations: levelling earthworks vs more complex and time-consuming racking; orienting modules for maximum fit vs north alignment for maximum energy yield; regular layout of strings to simplify installation and maintenance vs utilising all available land.

This can be some of the most time-consuming design optimisation and requires simultaneous consideration of electrical, civil, planning, energy and financial requirements.

5 – Civil and structural

The civil structural design of array mounting is a fundamental consideration. Design of footings to suit soil conditions requires extensive geotech, and there may be a trade-off between the effort required vs the risk of variation during construction.

Another key risk for solar farms is flooding. Once you’ve identified the potential flood conditions and possible effects, you will need to consider what mitigations are available under planning and environmental conditions.

Add to this all the operational requirements for vehicle movements and the cleaning and servicing of modules, and the civil and structural design becomes a significant work package.

6 – Lifecycle considerations

The sustainability of your solar plant doesn’t just make good commercial sense; it may also increase community acceptance.

Selection of robust equipment suitable for exposure to harsh and extreme weather will minimise the need for refurbishment, waste, and failure due to exposure to service conditions and duties that are beyond plant capabilities. This may mean designing elements of the plant that will have residual service life beyond the investment time frame. 

Just as ease of construction is a key design consideration, also consider the ease of demolition, site remediation and/or repowering. Ease of deconstruction of PV arrays and the ability to reclaim copper and other valuable metals may decrease your solar farm’s environmental impact.

The cost-effective level of design effort for solar farms is often thought to be low. However, we often encounter opportunities or imperatives to improve on standard approaches to suit a particular site or project.

Successful deployment of solar PV generation must include thoughtful design that considers the immediate challenges of rapid and repeated implementation while selecting from a vast range of suppliers and ensuring the greatest efficiency, operability and value for the long term.

If you would like to find out more about how Entura can help you optimise the design of your solar farm, please  Silke Schwartz on +61 407 886 872 or Patrick Pease.

About the author

Dr Chris Blanksby is a Senior Renewable Energy Engineer at Entura, and Entura’s lead solar energy specialist. Chris has undertaken and published research on the solar resource in Australia, and has led several due diligence and owner’s engineer projects for wind, solar and microgrid projects in Australia, the Pacific and Asia. Chris is currently leading Entura’s owner’s engineer team assisting the Government of Cook Islands to implement six solar PV microgrid projects, and build capacity towards their 100% renewable target.

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Planning a renewable energy journey in the Pacific

Like many stories of island journeys, the pursuit of high levels of renewable energy in the Pacific involves good planning and skilled navigation to stay safe and on course, and holds the promise of rich rewards.

Throughout the Pacific, island communities are embracing ambitious renewable energy targets , many as high as 100% renewables over the next decade or two. This isn’t surprising, given that these islands are already experiencing significant impacts of climate change, and recognise the environmental benefits of reducing or replacing carbon-intensive diesel power generation.

There are also sound economic benefits to reducing reliance on expensive diesel fuel, which remains the single largest expense to generate power in these remote locations.

The answer to meeting targets, while also reducing carbon emissions and costs, lies in power systems that use only renewable energy. However, transitioning to higher levels of renewable energy in power systems requires confidence that the renewables can provide the energy security, self-sufficiency and system stability required by these remote communities.

Renewable energy technologies may pose some challenges for reliability and quality of power supply, but remedies can be found in enabling technologies. In an isolated power system, matching the renewable technologies with the right enabling technologies at the right moment needs detailed planning.

Every journey needs a map

As each island community’s renewable energy journey is different, careful strategic planning is needed to choose the right solution, to integrate it in the right way, and to be able to scale it up effectively to meet increasing renewable targets and electricity demands.

Click image to view infographic.

Entura has been helping a number of Pacific island communities embark on their renewable energy journeys. Through this experience, we’ve developed a map of the key stages of the journey:

Stage 1: Planning – In this stage, we explore the status of the current power generation assets, determine what needs to be improved, understand the renewable resource, and investigate the cost of the renewable energy journey and options for funding it.

Stage 2: Introduction of renewables – In this stage, we begin by harvesting the ‘low-hanging fruit’ – introducing the renewables that we can without enablers or network upgrades, and without changing the control philosophy. At this stage, the renewables are perceived as mostly load offset, and could reach up to 15–20% of the island’s total energy demand. Few enabling technologies are necessary at this stage.

Stage 3: Expansion of renewables and introduction of enablers – As we progress beyond 15 to 20% renewable penetration, we need to stop, review and adjust course if necessary. To progress towards 35% renewable energy contribution to the power system demand, we need to adjust the system’s operating philosophy to integrate large-scale renewables, and introduce the appropriate enabling technologies.

Stage 4: Expansion of renewables and enablers – This stage marks the largest change in how an island power system is operated. As we move beyond 50% renewables, again we should stop, review and adjust course where needed. At this stage, power systems become very complex to operate and maintain as high renewable penetration can only be achieved through a delicate balance of multiple new enabling technologies working in perfect sync. The island community could find itself investing more in enabling technologies than in renewable energy at this stage, but this could result in a higher renewable energy contribution. It is also crucial at this point to consider changes to energy delivery, relationships with customers and to the utility’s procedures, and to building its personnel capabilities.

Stage 5: Approaching 100% renewables – As most of the major changes to the power system are introduced in the earlier stages, Stage 5 is about finishing off the journey. The ‘last renewable mile’ is usually the most expensive one, so this last stage is all about identifying enabling technologies and techniques that can bridge the gap between 70–80% and 100% renewable contribution, without significant increases in the cost of electricity.

Yap’s journey to 25% renewables

Entura has helped several island communities plan and begin their renewable journeys. One example is the island of Yap in the North Pacific.

We’ve been working with the Yap State Public Service Corporation to reduce Yap’s heavy reliance on imported diesel for power generation, and to enable the island to rely as much as possible on indigenous, renewable resources through an integrated high-penetration renewable energy remote area power system (RAPS).

After decades of operating on diesel fuel only, the system will soon reach 25% renewable energy contribution. Once completed, the project aims to enable Yap to experience up to 70% instantaneous renewable penetration when conditions allow, and to deliver an annual fuel saving of up to US$500 000.

Back in 2014, Entura helped the Yap community plan their renewable journey by embarking on Stage 1. Since then, Entura has helped the Yap utility to reach Stage 2 by integrating small amounts of solar and by building its capability to install and maintain solar arrays.

The Yap renewable energy development project is now entering Stage 3, in which a new breed of high-renewable-supporting diesel generators are being installed, major works are being carried out to install three 275 kW cyclone-proof wind turbines, an island-wide solar-controlling communications network for 500 kW distributed solar PV is being rolled out, and a centralised control system is being installed.

Once these activities are completed, the Yap power system will be firmly in Stage 3, and ready for future stages in Yap’s renewable journey.

On course for 100% renewables in the Cook Islands

The Cook Islands is a group of 15 small islands in the South Pacific, to the north-east of New Zealand. Entura is helping the Cook Islands on its journey to reduce reliance on diesel fuel and achieve greater energy security, self-sufficiency and sustainability through developing renewable power systems on six islands. The country’s goal is to generate electricity from renewable energy sources on all islands by 2020.

The islands of Mauke, Mitiaro, Mangaia and Atiu have small average loads of around 100kW each. After careful planning, upgrades to the distribution grid and programs to train and build local capacity, these islands will quickly reach Stage 5 of their journeys, operating at almost 100% renewable energy using solar PV and batteries, with diesel providing backup during longer periods of renewable energy resource deficiency.

A fifth island, Aitutaki, is currently at Stage 1, finalising the planning of its renewable journey. It will rapidly jump to Stage 3 as 1 MW of solar PV, a 0.5 MW power battery, new diesel generator and centralised control system start working together to deliver a power system with a renewable contribution of up to 25%.

Rarotonga is the largest, main island in the Cook Islands and operates a complex power system requiring meticulous strategic planning. This power system is already at Stage 2, with a renewable contribution surpassing 10% due to the contribution of residential and commercial solar. Entura is helping the Rarotongan utility to move towards Stage 3 by introducing an additional 1 MW of solar PV and enabling technologies such as energy storage, which will help the system absorb even more renewable energy.

The journey continues

It is often said that the end of one journey is the beginning of another. After a community has reached 100% renewable energy, it needs to continue its journey to maintain that status through proper operation, maintenance and asset management, to secure the system for years to come. This long-term asset management challenge involves attention to both physical and human assets, including capacity building, training and skills development for individuals and organisations.

Entura is bringing practical maintenance know-how to island communities such as Yap and the Cook Islands. And, through the Entura clean energy and water institute, we are helping to boost the skills of technicians and managers. By doing so, Entura is offering island communities a guiding hand from the start of the renewable journey right through to its destination, and beyond.

If you would like to discuss how Entura can support your renewable energy journey, please contact Silke Schwartz on +61 407 886 872 or Shekhar Prince on +61 412 402 110.

A version of this article has been previously published by RenewableEnergyWorld.com

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Planning for solar success

Planning regimes for large-scale infrastructure are rarely simple. Investing time and energy in planning for project approvals makes it more likely that your solar project will succeed.

In this third part of our series of articles on overcoming potential roadblocks to solar developments, we take a closer look at how to navigate the planning environment for utility-scale solar PV energy projects.

Unlike domestic solar installations, which are often exempted from needing planning approval, larger utility-scale solar installations are likely to fall within the general planning requirements for renewable energy, which can significantly restrict the areas in which they can be considered.

The increased flexibility of the size and location of solar installations, and their ability to match the needs of users and supplement the capacity of the network, means that demand for solar is likely to rise in areas close to urban development. Solar installations servicing schools and universities, commercial development clusters or even specific neighbourhoods are set to become more attractive. The solar farm may become the new hobby farm.

However, due to the current constraints of planning systems in several Australian jurisdictions, renewable energy developments of this scale on many of these sites may be prohibited or dealt with inconsistently. Development control systems across Australia are generally not set up to facilitate development; rather, they control impacts. They are not proactive and lag behind the market, struggling to respond to rapidly emerging technologies and changing market demands. They can be frustrating to navigate and hard to change, which sometimes makes obtaining approvals hard work.

Is it easier to plan for a solar farm?

The planning system tends not to differentiate between various forms of renewable energy generation, constraining all forms due to the perception and experience of those forms with greater perceived impacts (such as wind farms).

Compared with wind farms, solar farms are less likely to encounter concerns about potential impacts on human health, visual amenity, birds and bats, or noise levels and have fewer physical constraints on location. Although solar developments are likely to have less visual impact than wind farms, this will still be an important issue to consider, as will glare and the area of ground coverage. High ground coverage means more potential impact on existing vegetation and less opportunity for complementary land uses.

While solar developments have more flexibility than some other forms of renewable generation to respond to, and avoid, local constraints, many of the important siting requirements are common to all renewable developments, such as the essentials of grid connection and construction access.

A particular consideration for large-scale solar developments is that large areas of flat land are often located in areas outside of council jurisdiction, which are state-owned and can be encumbered by existing leasing arrangements. More remote areas have greater potential to involve existing Native Title rights.

Solar developments have the potential to re-use degraded sites, such as mine sites which are no longer viable, and can complement the existing management and rehabilitation regime for these sites while also offering long-term energy solutions.

Navigating the planning requirements

The planning system is complex, and its potential impact on the cost, timeframe and overall success of your project should never be underestimated. Approvals for solar developments are not necessarily more complex than for other renewable energy developments, but some aspects will differ and the specifics of your particular project need to be taken into account.

As with all large-scale infrastructure development, comprehensive regulatory mapping at an early feasibility level is essential to understand what approvals are likely to be required and where any dependencies exist. Critical approval paths, roadblocks, timeframes and likely information requirements can be estimated and guide stakeholder discussion.

Depending on the scale, location and potential impacts of the project, approvals may be required at the Commonwealth level (through the operation of the Environmental Protection and Biodiversity Conservation Act 1999), the state level (through the implementation of state environmental protection legislation), and the local level (through the implementation of a local development control plan or planning scheme).

Once the approval requirements are confirmed, detailed technical studies are essential for clearly demonstrating that the issues are understood and that the development (and any mitigation or management measures) is appropriate and effective.

The application documentation should be targeted to match and address the requirements of the relevant development control document drawing on the conclusion of the technical studies. It should include both a summary of the proposal that identifies the key issues and mitigation measures, and the detailed technical studies which underpin the planning assessment.

When permits are issued, it is usual for there to be a number of conditions requiring further actions or additional documentation to be submitted. Planning for these requirements is essential, as noncompliance can result in action by the responsible authority or, in some cases, lapsing of the permit.

Ultimately, your best chance of planning success is through fully exploring and understanding the development control provisions, permits, consents and the level of assessment that are required, obtaining high-quality and comprehensive specialist studies, and keeping a watchful eye on any project-specific hurdles.

If you would like to find out more about how Entura can help you overcome planning roadblocks for your solar development, contact Silke Schwartz on +61 407 886 872 or Patrick Pease.

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The art of solar grid connection

With 2020 and its renewable energy targets fast approaching, the race is on to deploy renewable energy developments in Australia.  Efficient and right-sized grid connection can get projects moving quickly and ensure future productivity.

In our previous article, Overcoming potential roadblocks when developing a solar farm, we outlined four possible hurdles to successfully delivering a utility-scale solar PV energy project.  One of these potential blockers is the grid connection.

Grid connection is about the system you’re connecting to as much as it is about the gear you’re connecting.  Understanding what lies beyond your plant boundary and the impact it can have on you and vice-versa can benefit the project as it comes to life, and make it a more valuable asset into the future.

Successful grid connection of solar plants is based on three rules.  Each of these rules isn’t necessarily specific to solar PV, but we think that solar PV is uniquely placed to adhere to them and consequently optimise the connection.

Rule 1: Don’t stray too far

The low visual impact and ubiquitous resource that solar PV utilises means there’s no need to hide your solar farm away or build it in a high-sun area (although some sun will be good).  Shorter lines between your site and the grid will save time and money.  The time is saved through shorter, less-complicated approvals.  The money is saved in design, construction and materials.  Pretty obvious.

This is a paradigm shift from previous renewables development though.  Wind developers, like their hydropower counterparts, have had to observe keenly the vagaries of climate, weather and geography to understand where viable sites might be.  These sites have often proven remote from the existing transmission system and so new lines or new upgrades to the transmission system have been required at great project expense.

Solar has an advantage in this regard and developers should capitalise on that advantage.  Spare capacity and land in the transmission and distribution networks can be used for solar farms without perhaps the need for the economies of scale that have driven the large wind farms and hydropower schemes of the past to stretch the megawatt capacity to support an expensive connection asset.

Rule 2: Don’t try to overdo it

Whether you build close to the grid or not, there’s no real advantage in over-burdening the grid with your generation.  The shared network is planned around efficient delivery of power to the customers.

Currently, customers are pretty well catered for in terms of generation sources, and so the likelihood is quite low of the shared network being augmented to allow greater power evacuation from a solar site with no cost to the solar developer.  This means that the grid constraints become a cap on the economic size of the solar farm.  These constraints are not just driven by the thermal rating of the lines but may also relate to voltage control or power quality.

The reality is that the more power you try to plug into the grid, the more you’ll have to pay to do so.  This is especially true if you push the limits.  So don’t – or if you think you can, or think you have to, then follow rule 3.

Rule 3: Do your bit

The Australian National Electricity Rules provide for a graded connection standard to be assessed based on the capacity of the plant being connected and the capacity of the grid to connect that plant.  The plant will be connected if it can meet automatic access standards or a negotiated level above the minimum standard.  The standards are generally assessed against the grid of today.

We know, however, that reductions in the level of synchronous generation may leave the grid weaker than it is now.  This weakening may impact the future capacity of the grid to support substandard generation connections.  This will mean that these generating systems that are substandard may be constrained or disconnected during weak system conditions.

This is a threat and an opportunity for new solar projects.  The threat is declining revenue as the grid weakens over time.  The opportunity is to not only avoid the revenue decline but potentially increase production opportunities or scalability of your asset.

This opportunity can be realised through two main avenues:

• Matching the capabilities of the solar farm to the needs of the local network: For example, if the network has customers nearby, it’s likely that those customers or the network equipment supplying them will be sensitive to swings in voltage profile.  A solar farm with good reactive capability and voltage controls could have higher capacity and/or a cheaper grid connection since the network operator won’t have to augment their plant.

• Providing transparency of performance capabilities: To gain advantage from these additional capabilities, they must be clearly defined and communicated.  This is most often done through clear documentation and the provision of accurate dynamic models.  Accurate dynamic models are already mandatory for plants over 30 MW in Australia.  They may well be good business practice for smaller installations too, depending on the impact the plant can have on the network.

The solar industry and the wider electricity supply industry in Australia are on an accelerated learning curve when it comes to utility-scale solar due to the rapid deployment of this technology.

Grid connection does not need to be a roadblock to the roll-out of solar farms , but it must be carefully considered not just as a hurdle but as a tool to ensure the plant continues to be able to inject to the grid as the grid changes.

If you would like to find out more about how Entura can help you overcome grid connection challenges when developing your solar farm, please contact Donald Vaughan on +61 3 6245 4279 or Ranjith Perera on +61 3 6245 4272.

About the authors

Donald Vaughan is Entura’s Technical Director, Power. He has more than 25 years of experience providing advice on regulatory and technical requirements for generators, substations and transmission systems. Donald specialises in the performance of power systems. His experience with generating units, governors and excitation systems provides a helpful perspective on how the physical electrical network behaves and how it can support the transition to a high renewables environment.

Ranjith Perera is a Specialist Power Systems Engineer at Entura.  He has over 22 years of experience in Australia and South-East Asia, working on customer and generation connections and broader power system analysis.  Ranjith has provided power system advice on a wide range of network augmentations, network planning and system stability in Australia and internationally. These studies included option analysis in transmission planning, constraint analysis, determination of reactive support (dynamic or static) in system stability / TOV and detail load modelling in voltage stability. Ranjith also developed voltage recovery guidelines to TNSP based on regulatory requirement and customer equipment tolerances.

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How can we manage a network with more renewables?

Can our network and market frameworks support two to three times more renewables in Australia in the next 10 to 15 years without radical or innovative actions?

Once upon a time, we had an electricity system that was dominated by large users and large producers, and everyone else just tagged along.  It needed very few points of control.  Demand was easy to predict, as was the availability and cost of generation.

This is increasingly not the case.

The predictability and consistency on which the market and the network relied are being eroded by changes in how we produce and consume electricity.  The efficiency benefits of the market are being undermined and it seems unable to find a ‘new normal’ that works.  At the same time, the technical robustness of the electricity supply is being undermined through the reducing share of dispatch of synchronous generation.

These effects are only beginning to emerge in the wider National Electricity Market (NEM).  We are suffering from increasing uncontrollability, unpredictability and variability.

Uncontrollability

As wind and solar PV replace synchronous generation in the NEM, system inertia and fault levels will steadily decline, along with the availability of frequency-control ancillary services (FCAS, or ‘spinning reserve’).  More self-dispatched generation also limits the market operator’s ability to efficiently manage transmission constraints.

Unpredictability

We can use statistical models to predict demand pretty accurately unless we factor in customer storage.  Installation of uncontrolled storage adds a degree of uncertainty to the demand.  The current pre-dispatch followed by real-time dispatch methodology may not be capable of dealing effectively and efficiently with this uncertainty.  Furthermore, the factors determining take-up of new technologies are difficult to predict.  This uncertainty makes it more difficult for network planners to forecast and hence maintain capacity in the network.

Variability

Increasingly, generation dispatch patterns (and load patterns in some regions) depend on non-market variables like sun and wind (and rain).  This variability can lead to a wide range of valid system dispatches, which in turn may require a wide variety of network supports, such as reactive power support from SVCs and the like.  Interconnector capacity requirements vary depending on dispersion or concentration of generation relative to demand.

How might a low-synchronous-generation network be managed?

In many ways Tasmania provides a glimpse of the future in terms of how a low-synchronous-generation network may be managed.  Since Tasmania has been connected to Victoria, generators, major customers and the network service provider, with support from Entura, have collaborated to extend and enhance the Tasmanian power system’s ability to cope with what is already in excess of 70% non-synchronous generation under high wind and high import on the interconnector.  While the interconnector can provide some frequency support, this support is capped within the capacity of the link.

The solution in Tasmania is to reduce demand for frequency control, increase capacity to supply frequency control and actively manage fault level and inertia.  This has required detailed understanding of the power system dynamics within the Tasmanian power grid as well as innovative engineering to understand and adapt hydro generators to extend their capability or flexibility. The solutions range from tweaking the control systems of individual generating units to establishing and coordinating system-wide protection schemes and constraint equations.

This experience shows that understanding the fundamental characteristics of a power system and its likely operating modes, and a common purpose and resolve to enhance its operation, can lead to an expanded technical envelope in which the electricity market can seek a cost-effective outcome.  It has required collaboration across the sector including equipment manufacturers, owners of windfarms, hydropower stations, interconnectors and large customers.

Can this experience be replicated elsewhere? 

Different power systems may demand a different set of solutions, but the fundamentals remain the same.  A functioning AC power system needs inertia, fault level, frequency and voltage control as well as energy sources to function to an acceptable standard.  Each power system will have its own sweet spot for providing these requirements.  Inverter-based generators (solar, wind and batteries) can provide inertia-like responses for instance and so may reduce reliance on synchronous machines for that requirement.

A bigger question is: will the market takes us there or will it lead us down a blind alley of misguided self-interest?  We are already seeing some murmurings of market reform that may ultimately lead us to the right long-term solution, but I’m not sure that we can always rely on market-led transitions, especially where the transition has not been envisaged as part of market design.  This may be a misplaced leap of faith.

It’s clear that no single solution is going to sort this out in most cases.  It’s also clear that some level of collaboration will be required to make the transition work smoothly.  The planner must also consider technological change and customer expectations; else we run the risk of over-capitalising on solutions only for them to become redundant and ‘stranded’.

Ultimately, we know the challenges are not insurmountable but we also know that the solution is likely to be arrived at through care and deliberation rather than market meanderings.

If you would like to find out more about how Entura can help you adapt successfully to the rapidly changing market for electricity generation and energy services, contact Donald Vaughan on +61 3 6245 4279 or Wayne Tucker.

About the author

Donald Vaughan is Entura’s Technical Director, Power. He has more than 25 years of experience providing advice on regulatory and technical requirements for generators, substations and transmission systems. Donald specialises in the performance of power systems. His experience with generating units, governors and excitation systems provides a helpful perspective on how the physical electrical network behaves and how it can support the transition to a high renewables environment.

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Overcoming potential roadblocks when developing a solar farm

If you are planning a utility-scale solar development, how can you avoid the potential pitfalls and maximise success?

We’ve heard the equation so many times, and it seems so simple: take plenty of sun, add the rising costs of energy, factor in the rapidly falling costs of solar technologies, and throw in an increasing trend towards fossil fuel divestment and social and environmental credit for supporting renewable energies, and you’ve got a no-brainer: solar power is good business.

But while Australia ranks amongst the world leaders for the uptake of smaller scale solar, there is still enormous untapped potential in the utility-scale solar photovoltaic industry. The country has a very large area of high insolation, the solar resource is less variable than wind, solar farms don’t usually have the same level of impacts or objections as wind projects, and sources of funding appear to favour solar over other renewables.

So what could possibly go wrong? Well, there are a number of hidden risks that could have the potential to ‘make or break’ a project.

Potential roadblocks when developing a solar project

In each phase of a renewable energy project, there are some potential roadblocks and challenges that could cause costly delays or reduce your expected return. The more you can do as early as possible to identify, understand and resolve these challenges, the more likely your project is to succeed.

Click to download infographic

The stages of a utility-scale solar project (site identification, feasibility assessment, approvals, financial close, construction and operation), and the possible pitfalls in each stage, are reasonably similar to those encountered in all renewable developments regardless of technology.

Having worked on a wide range of renewable projects in Australia, we have learned some key lessons in how to successfully bring renewable energy projects to completion and operation, and how to avoid costly surprises, delays and other setbacks.

PLANNING APPROVAL

If you’ve already been involved in developing any renewable energy project, you’ll know that to maximise your chance of smooth and timely progress, one of the most important investments is early and effective stakeholder engagement. This includes identifying the main issues affecting the social acceptance of your project, such as the history of past projects, council objectives, permit requirements and the requirements of the local power utility.

No doubt, you’ll have experience in developing a comprehensive community engagement plan, with open, honest and extensive consultation. You’ll already have navigated the environmental constraints at project sites, including fauna, flora, Aboriginal heritage, historical heritage, access, stormwater and erosion management, among others. So, in terms of the planning process, is there ‘nothing new under the sun’ when it comes to solar?

Utility solar projects may look reasonably easy, and to some extent this is true. However, most of the same planning processes and timelines will apply as for other developments (including the same long turn-around times if you need to revise anything during the process, or expand the scale of the project). Therefore, as you would for any project, be sure to fully explore and understand the development controls that apply to the site, through the local planning scheme or environmental plan, the various permits and consents that are required to authorise the use and development, and the level of assessment that will be required for permits. And ensure that the specialist studies undertaken are as high quality and comprehensive as you would for any other development.

As well, keep particularly alert for project-specific pitfalls such as airport reflections, very high ground coverage and penetration, working in flood zones, and so on.

Learn more about planning for solar success.

GRID CONNECTION

Proximity to the grid is one of the most important criteria for selecting a site (along with the available solar resource, suitable topography and land zoning). We strongly recommend engaging early with the power utility to ensure capacity and access is available, so that you can export your generation without curtailment. There is also now an extensive range of published information on distribution networks, including zone substation connection capacity, which can provide valuable insights into the best place to connect.

Although your dynamic modelling and connection studies will include the obvious assessments (such as  reactive power capability and fault levels), your project will also benefit from thorough investigation of generating system response to frequency or voltage disturbances, impacts on the network capability, and remote monitoring.

Consideration of network support is another important element of discussions with the power utility and opportunities should be investigated at an early stage as they can shape the details of plant design. In the long term, these supports may form the basis for additional revenue streams or competitive advantage where network stability constraints arise.

Learn more about the art of solar grid connection.

DESIGN

In relation to the design of your solar project, how confident are you that you are using the most appropriate technology, such as modules or tracking systems (where practical and economically viable)? As you select your equipment, be sure that it is certified to the relevant Australian standard, and that all parts are compliant. You should also check that you have included sufficient isolation points, and whether fuse, switchgear or circuit breakers are the most appropriate.

When you are selecting and dimensioning your inverter, consider how it will react if instantaneous condition exceeds the maximum power rating. Does the attempt to change voltage to manage the condition lead to shut down? How can you prevent this, and how did you derive your optimum inverter concept, your string and DC/AC ratio?

In your overall design, consider the implications of a failure in the system. By adopting an AC electrical ring topology, for example, you could ensure the minimum loss of generation. You should also investigate how you will monitor failures and identify faulty modules within an array of thousands, and how to minimise near and far shading on parts of the arrays.

Another important aspect is to implement a ‘Safety in Design’ methodology and check that construction workers and your ongoing personnel have the appropriate training to operate DC and AC equipment and to conduct procedures both effectively and safely.

While almost all aspects of solar plant design appear simple and generally low risk, we know that careful consideration of plant lifecycle can lead to more efficient construction, operation and refurbishment. Good design can reduce failures, lost production and maintenance requirements. This is true of any project, solar is no exception.

Here are the six essentials for solar farm design.

FINANCING

Unlocking secure and adequate project finance is about much more than calculations of financial return on investment. It’s also about offering the investor confidence that your project has adequately considered and planned for all potential risks across the spectrum of financial, technical, stakeholder, community and environmental issues.

To bring your project to financial close you need an offtake agreement of sufficient length, a grid connection agreement, land agreements for the site and transmission route, developmental approval, a bankable yield estimate and a selected delivery model.

Financiers are more likely to provide better terms if there is less uncertainty for the revenue stream over the debt financing period, so the longer the warranty period on the delivery contract the better. Consider how you will monitor defects, and investigate third-party warranty insurance for the lifetime of the project.

Another key factor in offering confidence to investors is the reliability of the site’s solar resource assessment and the project’s energy yield. We recommend that a variety of reliable and appropriate solar resource datasets, with at least 10 years of data, be considered, as well as short-term on-site ground-based measurements. Financiers will also expect that you factor in the possible year-to-year variation and the uncertainties of resource measurement and energy estimation, in addition to loss assumptions and degradation.

A thorough due diligence investigation on your modules will mitigate risk and offer your investors further certainty and confidence. When assessing the modules, make sure you look at the technical test data and its implications for failure rates and degradation, but also explore the track record and capacity of the manufacturer, particularly considering the risk of manufacturer insolvency.

Take a closer look at some key risks often scrutinised by lenders and investors.

If you need support with any aspect of your solar project, or would like to discuss how Entura can help you maximise your project’s success, contact Silke Schwartz on +61 407 886 872 or Patrick Pease.

About the author

Silke Schwartz has over 15 years’ experience in the renewable energy industry in Australia and around the world. She has been involved in the technical due diligence of renewable energy projects in Australia, India and China, including condition assessments, technical assessments and performance reviews.

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How can businesses get more value from their investment in solar and storage?

What do you need to know to minimise your risk and maximise the value of your commercial-scale solar and storage system?

In our fast-moving environment, the time for businesses to act on solar and storage is now. Early movers are well placed to capture the best opportunities from commercial solar generation (large solar arrays in places such as shopping malls, warehouses, universities or airports) and other types of mid-scale embedded generation – and, notably, network operators are already moving ahead with some of their own innovations and installations to add value to the electricity network.

The business case for investments in commercial solar and storage are made almost entirely on the basis of projected savings on electricity bills assuming continuation of current tariffs. However, current tariff structures don’t reflect the way network operators experience costs to supply electricity, and the threat of future adjustments can make these sizeable investments risky for astute businesses. So how can you make the best of the available opportunities and add value to your investment?

As you prepare to act, you need to understand some key factors:

• how and where you can add value
• how to benefit financially from embedded generation and storage by working with network service providers (i.e. what schemes are available)
• how to manage the technical and commercial risks, and
• how to make the most of falling technology prices (particularly for batteries).

Behind the meter, or grid support?

Most existing embedded generation is rooftop solar PV installed ‘behind the meter’, reducing the business’s electricity bills, generating the business’s energy needs, and improving the business’s overall carbon footprint. The size of these systems has usually closely matched the load, and export to the grid has been less of a priority.

However, as storage technologies become cheaper and more readily available, greater scope emerges for renewable embedded generation to export power into the grid: providing extra generation in capacity-constrained areas, supporting peak demand, and reducing or deferring the need for grid upgrades or extension at the fringes of the grid or in new developments. They can also support reliability and power quality standards.

In this market, businesses considering solar and storage need to think of themselves as project developers. One way for developers to capitalise on the available prospects, minimise risk, and add value to a commercial embedded generation investment is to work out how to turn these possible forms of network support into additional revenue streams.

Benefits of network support

When embedded generation and storage adds value to the network, significant benefits are available for both commercial generators and network operators, and these benefits can be shared. Yet, despite these opportunities, there are still very few examples of mid-scale systems being recognised to provide network support.

Network support is typically where a system that is not part of the traditional network, such as solar, wind, or batteries, helps the network to deliver its function of reliable electricity supply to customers. As a simple example, a network operator facing rising demand in a specific area would traditionally plan for a substation upgrade. But if it costs less, they may consider a network support strategy to install local embedded generation and storage.

Whilst regulatory reform is underway to formalise parts of this, plenty of potential opportunities exist now. To make the most of these options, proponents need a good understanding of the key issues, and close collaboration with network service providers.

New developments, new possibilities

Opportunities for network support at existing premises can be very valuable, but these only exist in specific locations. Such prospects are certainly worth exploring; however, it is in the context of new developments that opportunities are becoming most abundant.

Where a new connection is required for a residential development, a large shopping complex or a similar large development, an opening exists to optimise the combination of baseload power supply from the network with peaking power from embedded generation such as commercial solar and/or storage. This option is particularly effective where the local resource coincides with the load, such as a good daytime solar resource that matches a daytime shopping centre load.

The embedded generation or storage may be able to significantly reduce the capacity requirements for the network connection, and alleviate broader network constraints that would need to be addressed if the entire additional load were drawn from the network. In all cases, battery storage increases the available possibilities by addressing instances where peak demand exists but generation output is not available, or where renewable energy generation does not coincide well with load.

Preparing for action

A good place to start exploring the possibilities for commercial solar and storage in more detail is Australia’s Clean Energy Council report Grid Support: Revealing Mid-scale Generation and Storage Potential. The Clean Energy Council engaged Entura to conduct this extensive study because we understand the regulatory constraints, the technology and its applications, and the multiple revenue streams that make up the business case for its proponents.

The report is based on detailed analysis of the commercial, technical and regulatory aspects of commercial solar and storage, and identifies the key areas that still need to be addressed so that network operators and commercial solar developers can fully harness the potential benefits these technologies can offer the grid.

To discuss how Entura can support you to best take advantage of the benefits of mid-scale embedded generation and storage, contact Chris Blanksby on +61 408 536 625, Patrick Pease or Silke Schwartz on +61 407 886 872.

About the author

Dr Chris Blanksby is a Senior Renewable Energy Engineer at Entura, and Entura’s lead solar energy specialist. In addition to leading the above-mentioned report for the Clean Energy Council, Chris previously led the work on demand-side-management opportunities for the Clean Energy Council. Chris has undertaken and published research on the solar resource in Australia, and has led several due diligence and owner’s engineer projects for wind, solar and microgrid projects in Australia, the Pacific and Asia. Chris is currently leading Entura’s owner’s engineer team assisting the Government of Cook Islands to implement six solar PV microgrid projects, and build capacity towards their 100% renewable target.

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