Powering a greener mining future with hybrid renewables

This article reflects on a panel discussion chaired by Ray Massie at the Energy and Mines Australia Summit 2023, which you can read more about here.

The discussion about powering mines with renewable energy has moved a long way in a short time. As the imperative to go green has escalated, the mining sector has grown hungrier for viable, rapid and cost-effective strategies to decarbonise, build greater social licence and tap into the competitive market for products with a lower carbon footprint. Integrating cheap, abundant renewable energy into mining operations is the natural solution.

These are exciting times as the sector moves far beyond the ‘why’, ‘whether’ and ‘when’ of renewables – and digs much, much deeper into the nuances of ‘how’.

Early forays into small hybrid off-grid renewable energy systems have demonstrated and built confidence in the technology – so there is no longer any question in the mining industry of whether off-grid hybrid renewable systems will work. Off-grid hybrid projects aren’t small test beds anymore. They’re ground-breaking, large-scale, cutting-edge renewable power systems of the future, able to be deployed on a fully commercial basis with clearly understood risks and operational adjustments. In many ways, the mining sector is out ahead of the pack, and the deployment of renewables on off-grid mine sites is offering lessons for the wider power sector and the future of the grid.

With many of the early technical risks resolved, the driving focus now is how to take full advantage of what a hybrid system can offer. How can the system be optimised to maximise its benefits? What’s the required level of reliability? How much storage is enough – and in what form?

Of course, every mine site is different, so there are no one-size-fits-all answers. And today’s answer may not be the right fit for tomorrow, given the rapid and continuous transformation of the energy landscape – in terms of technology advances, policy shifts, price volatility and global trends. It’s a dynamic space.

Integrated control and storage change the game

Traditionally, the relationship between mining operations and power supply has been a relatively simple transaction requiring a given amount of power with a set level of reliability and availability. The modelling of the power system was based on simple load metrics and power quality dictated by the capabilities of thermal generation plant. This equated to a very simple, flat cost of energy with any variance at the macro scale driven by changes in the price of fuel.

As we all know, when we switch over to multiple intermittent and variable generators, things become more complex. One of the keys to unlocking the benefits of a hybrid renewable system is the integrated control approach. With the correct control philosophy in place, you have many more ‘levers’ that can bring each element into play for a given operational mode or system event. This enables achievement of the levels of power quality and reliability that are needed, rather than being limited to the levels that traditional thermal plant could supply.

With this sophistication of control, we can start to think differently about reliability across the whole mining operation. Does the mining plant process or works need the same reliability or availability across everything all the time? Perhaps, for example, power supply for pumping may not require as high a level of reliability as other more critical areas of the plant. A clear understanding of the true reliability needs will help derive the optimal design at minimal cost.

When storage comes into the mix, we can also start to think differently about how to best match energy supply, timing of energy-intensive activity, and storage of excess energy to get maximum value from the renewable resource and minimise both the cost of energy across the operation overall and the cost per tonne of the mine’s output. The economics of long-duration storage are improving all the time.

New horizons for energy storage

Although the technology and the sector have travelled a long way already, there are still issues to finesse. One area of uncertainty is the optimal and most cost-effective storage technology and duration.

Going back a decade, the economic storage duration was 10 to 20 minutes, using the battery primarily for its discharge capability. Now we are seeing economic storage durations approaching 4 hours, which lend themselves to energy-shifting roles in which the charging capability comes into play as well as the discharge mode. The economics of longer duration storage will continue to improve but the optimum arrangement will vary site by site.

Funding for advancing novel long-duration energy storage (LDES) technologies has increased by 36 times over the past 5 years[1]. While lithium-based batteries still dominate and are likely to continue to do so for the foreseeable future, many more types of storage are now possible, including metal-air, pumped hydro, compressed air, flow batteries, gravity, thermal and various novel chemistries. Some storage technologies require specific topography and geology, for example pumped hydro and large compressed air storage, and others are at varying stages of technical readiness. Flow batteries of various chemistries are experiencing a significant amount of support aimed at breaking through the long-term storage cost barrier, though this is yet to be achieved at scale, and more likely to be competitive at longer durations (>10 hr) and in larger sized systems (>100 MW).

It is clear, however, that finding the best LDES for a mine project is not just for the mining sector to solve alone. The entire global power industry is looking at storage – and the mining sector can take full advantage of this as LDES evolves. What the mining sector can do right now is to identify the energy use and demand side opportunities that various storage durations could unlock for their projects.

Another key learning we have found over years of hybrid system development is that not every bit of energy produced by renewables needs to be stored. Some can be spilt or, better still, adjustments can be made on the load side to better match the variability in generation. Once the system stability, reliability and demand-side opportunities have been addressed, the storage of ‘spill’ really comes down to economics, which will change over time as storage costs decrease.

Collaboration and risk management

With all these new approaches and possibilities – and the many factors that always come into play such as mine life, capital limits and risk – it’s possible to over-analyse. Not every new project needs to break barriers and set new records. There is definitely still a place for choosing the low-hanging fruit, as the primary case for renewable hybrids being cheaper than thermal-only is well established. You will never really be able to answer every question in a single project – or even predict every question that might arise.

This is where you simply don’t have to go it alone. The key to overcoming hesitation is collaboration. Getting the correct advice is always worth the investment, as is sharing learning at an industry-wide level. There are many players that specialise in one or more aspects of the future mix of technology, mining process, hybrid power operation, renewables knowhow, integration skills, commercial thinking and so on – and bringing these skills together is a must.. Collaboration is the key to solving problems, reducing risk and its appropriate allocation, and a successful project that will benefit all industry players more than competition and working in isolation.

We also believe in learning by doing, through delivery of a specific project. Forming a group of key parties to drive forward a tangible project makes it far more manageable. In innovative projects, ‘pushing risk through’ often just comes back as significantly increased cost. A better approach in these cases is a shared risk profile. The learning is a significant part of the return in early adoption.

Are the right people and the right materials available?

The industry is already experiencing a shortage of experienced hybrid system operators. This needs to be managed through increased training and backup. We believe that operational personnel should be engaged very early in the design of a hybrid power system so that they can have input into development of the system, gain familiarity with it, and consequently feel a level of ownership of the assets.

It is also important to have a close relationship between those involved in the mining process and those operating the power system. For the power system operators, this is a chance to better understand the criticality of various mine plant processes; for the mine operators, it’s a chance to get a better understanding of the mix of operation modes that can be used to meet the mine’s changing power needs.

In many ways, the people skills and resources needed across all the project delivery stages (design, deployment, operation, maintenance and support) are more important than the technology – and this needs to be considered carefully for hybrid projects to be successful.

Finally, neither the mining industry nor the energy sector at large will be able to transition to renewables if we don’t have the right minerals and materials on hand to manufacture clean energy technologies such as wind turbines, solar panels and batteries. Having the mining industry supply these resources in a sustainable way is a powerful contribution to the clean energy transition.


Ray Massie has more than 30 years of expertise in renewable energy technology. He managed the development phase of the Hydro Tasmania iconic King Island Renewable Energy Integration Project (KIREIP) and Flinders Island Hybrid Energy Hub as well as undertaking key roles for hybrid system projects at Coober Pedy, Rottnest Island and more recently EDL’s Agnew Hybrid Renewable Microgrid powering Gold Fields’ Agnew Gold Mine and Scott Base in Antarctica.

Entura is an expert in hybrid off-grid renewable energy systems, from our world-leading King Island Renewable Energy Integration Project through to large-scale off-grid mining solutions such as EDL’s Agnew Hybrid Renewable Microgrid, powering Gold Fields’ Agnew Gold Mine. If you would like to talk to us about integrating more renewables and storage into your energy equation, contact Patrick Pease, Donald Vaughan or Greg Koppens.

[1]The long and the short of energy storage tech”, Climate Tech VC (CTVC), March 2023


What is the value of conventional and pumped hydro storage in a transitioning energy market?

Cluny Dam, Tasmania

Entura’s Technical Director Power, Donald Vaughan, presented a paper at the global CIGRE Symposium in Cairns, Queensland in September 2023. This is a short summary of the outcomes of the analysis presented in his paper, regarding the value and roles of conventional hydropower, pumped hydro and battery energy storage as the power system transitions to a greater proportion of variable renewable energy in the form of wind and solar PV.

There is a growing need for firming and/or storage in our power systems as we move from predominantly dispatchable sources of power to variable renewable energy (VRE). In the Australian context in the National Electricity Market (NEM), the volume of storage required is expected to be around 46 GW (640 GWh) by 2050 (AEMO 2022). Multiple sources, technologies and methods are being considered but it may be that conventional hydro as well as the more obvious pumped hydro and battery energy storage (PHES and BESS) can play a role.

How do we value storage?

Storage can be valued in many ways. For pure storage, like BESS and PHES, value in a market sense can be measured based on the arbitrage between charging and discharging. Similarly, we can place value on a firming function for VRE. It is more difficult to value the restraint of generation at one time so that stored or withheld energy can be used later. This is the kind of storage offered by conventional hydro sources.

One way of thinking about value is through a measure of realised value vs average value in the market for a particular generator or group of generators. This ‘value factor’ approach is an appropriate measure for storage if we are measuring storage as a contributor to meeting market demand (either local or via interconnections).

One of the problems with the value factor approach is that it is difficult to apply properly without considering market price changes. Introducing plant that can effectively change demand profiles (such as PHES or BESS) will also change the market price, making it difficult to calculate value factors without complex market modelling.

We can instead measure the value of storage by assessing its ability to firm VRE. The measure is based on the ratio of smoothed to unsmoothed VRE with and without the storages applied.

Where there are large amounts of VRE, flexibility from market participants can be valuable. In terms of hydropower generation, conventional hydro plant (storage, Run of the River and head waters) has sufficient flexibility to provide significant market value for modest levels of VRE.

The scale of the transition to VRE will, however, exceed the capacity of conventional hydro to manage variability. Other forms of firming and actual energy shifting, rather than just energy withdrawal (as conventional hydro provides), will be required once the energy balance tips towards energy coming predominantly from VRE sources, with the associated need to manage large diurnal variability as well as longer, weather-based variability. Pumped hydro and battery energy storage will play an important role in providing this more flexible storage.

The role of PHES and BESS in firming

The BESS high power-to-storage ratio allows it to respond to a series of short-lived surpluses or deficits. The PHES deep storage allows it to manage longer duration surpluses or deficits.

The ultimate mix between PHES and BESS in the market is likely to be driven by several factors including the rate of VRE development relative to the level of inter-connection, load growth and VRE mix.

The nature of the VRE will also play a role in determining the storage mix. A predominance of solar will lead to a diurnal pattern that will allow all storage forms to recharge more regularly than would be the case with wind alone. This may allow shallower storage to manage evening peaks with deeper storage reserved for baseload operation overnight. 

The economics of BESS and PHES will also play a role in determining the right balance. The market demand for batteries for other purposes and the high market demand for power electronics may yet lead the price/MW of these two storage forms to begin to converge and to limit the depth of storage that will be possible using BESS. PHES on the other hand requires long-term planning, complex approvals processes and less certainty in terms of capturing value from the market. The Integrated System Plan (ISP) of the Australian Energy Market Operator (AEMO) forecasts a large requirement for PHES as deep storage and some very large projects are beginning to be planned.

As these factors play out, the appropriate mix of BESS and PHES will become clearer – but both will certainly play a role in Australia’s clean energy transition.

For more information about the analysis behind his paper, or to discuss how conventional hydropower, pumped hydro and battery storage can be valuable to your situation, contact Donald Vaughan.

How to avoid analysis paralysis

Modelling has a very important role in every sphere of engineering. Complex mathematic models help us better predict and understand behaviours and performance so that we can solve technical problems, push the boundaries of applied science, and optimise construction and manufacturing.

We use finite element models (FEM) to determine the forces, stresses and deflections of a complex structure. We use computational fluid dynamics (CFD) to analyse complex three-dimensional hydraulic problems and determine flow vectors, velocities, water depths and pressure fluctuations. A complex finite difference model (such as FLAC) helps us model complex geotechnical problems. A rainfall–runoff model supports our understanding of potential flooding along a river channel.

In the 30+ years that I have worked in civil engineering, computing power has increased dramatically. As a result, modelling tools have become more powerful, enabling engineers to model increasingly complex principles and problems. For example, we can model non-linear stress–strain properties of materials, rather than simply assuming that they are linear. We can model the turbulent nature of water hydraulics, rather than assuming that the flow is laminar.

The advantage of having more powerful and more extensive modelling tools available to engineers is a significant improvement in our understanding and therefore, in many cases, a corresponding improvement in the engineering. But there is a potential downside: the risk of ‘analysis paralysis’, which is when our ability to make timely decisions is impeded by over-analysing or over-thinking scenarios or alternatives.

I am not a psychologist, but some say the root cause of analysis paralysis is the fear of making the wrong decision, choosing the wrong option or missing out on a potentially superior solution. This fear drives ongoing analysis, and the result is a loss of the expected or potential value of a timely, successful decision. Rather than making a decision, we try to preserve all existing options, continuing to analyse and refine.

This might look like a lower risk strategy, but it is actually a losing strategy. Complex modelling with an overload of scenarios, alternatives, sensitivity analyses or options can overwhelm the situation, making it very difficult to reach conclusions and make the decisions that are inevitably needed to move the project forward. This can potentially cause a bigger issue than if a decision had been made earlier. Prolonging the modelling and analysis phase will merely postpone, not eradicate, the risks associated with implementation. At some point, implementation will be expected.

It is very important to always remember the purpose of modelling, which is to help us understand a problem in order to make decisions – in many cases, engineering decisions. Engineering should drive the process. Although we may be able to refine a model further, perhaps we already have sufficient understanding to make the necessary engineering decisions, so the extra refinement is superfluous. Just because you can refine a model, or add complexity to a model to better reflect reality, doesn’t mean you should. The more refined and complex a model becomes, the more time is required to develop, analyse and interpret the results. It also becomes harder to validate the results, which is critical; blind faith in any complex numerical model is dangerous.

Early in my career, in relation to finite element modelling of dams, a mentor advised me to start simple with the model, validating the results against real data and known engineering behaviours to develop confidence in the model before adding further complexity. A big driver for this process was the extensive run times of these models three decades ago. Despite the progress in modelling over the decades, I believe that there is still a lot of merit in this gradual process of building complexity into a model. However, due to the software and computing power available today, a high degree of complexity is often built into a model right from the start. When this occurs, the modelling can become less of an engineering tool and more like a dark art.

The computing power available today certainly offers engineers access to some amazing inputs for our design processes. But numerical modelling does not replace the engineering. No matter how much modelling we do, we must still eventually make some important engineering decisions. If further refinement of the model won’t change the engineering decision, it’s time to stop. Don’t fall into the trap of analysis paralysis!

In summary, my tips for avoiding modelling paralysis are:

  1. Keep the purpose of your model in focus.
  2. Start simple and add complexity to your model only as required.
  3. Validate your models and ensure confidence in the results.
  4. Before refining the model, consider whether it will help your decision-making or if you already have sufficient understanding to make your decision.
  5. Remember that modelling does not replace good engineering practice and decision-making.
  6. Know when to stop modelling. Come back to the problem you are trying to solve or the decision you are trying to make.

To talk further with an Entura specialist about your modelling challenges, contact Richard Herweynen.

About the author

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.


How can an Owner’s Engineer smooth the progress of a renewable energy project?

Throughout the renewable energy sector, there are plenty of examples where decisions made during the planning and procurement phases have caused difficulty during construction and affected future operations. A smoother construction process is to everyone’s advantage – avoiding cost blow-outs and time over-runs, and a lot of unnecessary stress and sweat.

An experienced Owner’s Engineer can provide an extra level of continuity and foresight to help reduce risk and minimise surprises. Having independent eyes focused on ‘doing it right’ from the earliest stages is an investment in keeping a project on the path to success.

Here we discuss a few simple and practical opportunities where an Owner’s Engineer can make a meaningful difference to progress.

Providing critical continuity

Continuity during the development lifecycle of a renewable energy project can sometimes be difficult to maintain. Transitions occur when project ownership changes, people come and go, government policy shifts, and when the project transitions from one development phase to the next. An Owner’s Engineer who is part of the project through all the phases of development can add a valuable perspective and source of knowledge to the project team through these transitions.

The Owner’s Engineer can apply industry-wide learnings and experience to identify risks and detect opportunities to maximise value in both the immediate detail of the project as well as later stages of the development’s lifecycle. This increases the likelihood that the transition between lifecycle phases – such as when a project advances to construction, or the handover of a newly constructed asset to an operations team – will be smooth and successful.

Maintaining order and good process

In a project where schedule risk is a big concern to all involved, sometimes good process falls to the wayside. The appropriate order of studies, design validation and construction can be impeded by a desire to get construction underway as soon as possible. Good forethought, data, modelling, discussion and design validation take time, but they are essential inputs for a successful outcome. A rush to get construction underway before this process is concluded increases the chances of re-work being required – a risk that’s always best avoided.

Identifying knowledge gaps

Having an independent Owner’s Engineer involved in a project from the beginning of the development and design process means that there is an independent expert who can review early technical studies, and identify where there may be gaps in the analysis. These early technical studies ― such as geotechnical studies for foundation and road design, and soil thermal resistivity testing to inform the right choices for cable sizing and trenching ― can have major impacts on the cost and effort expended during the design process, and the type of design that is required for a successful project. If these studies aren’t completed early enough, or thoroughly enough, there will be higher risks for the EPC contractor bidding on a project, hence higher cost. There may also be delays in the design process and at critical construction stages, with costly ramifications.

Thinking through logistical constraints at planning application stage

Construction of a wind farm, solar farm or hybrid renewable project is always a logistical challenge. For example, wind turbine components are massive, and getting bigger all the time. Rural roads are rarely of the width, camber and capacity to handle the large vehicles needed to carry materials, components or machinery. They may also not cope well with the volume of truck movements required. Community preferences and planning constraints can also limit the number of truck movements to and from sites per day.

Another important consideration in the construction of large renewable energy projects is how to move cranes around the site. In the case of a wind farm, will it be more effective to choose a crane that can be disassembled after erecting each turbine, moved in sections, and reassembled at the next turbine site? Or will it be quicker and cheaper to drive a crane between turbines? Given the potential for the width of the crane to overflow the width of the local roads, such a decision needs to take into account the potential for additional environmental approvals for a wider area of disturbance.

These challenges need to be carefully considered as early as possible in the planning application stage. Time and effort spent on the planning application can make a big difference to the ultimate project outcome. As the project progresses, clear sequencing and communication is vital for keeping things moving smoothly while also adhering to the constraints of construction and transport conditions.

Writing and enforcing clear specifications

A project’s technical specifications and the contractor’s response to them ultimately determine the end quality of the project. For both the owner and the contractor, it is vital that specifications are unambiguous and reflect the owner’s technical requirements and desired quality for the project. The Owner’s Engineer can help improve specifications based on their experience, for example specifying what sort of fixings can be used to hang cables below the solar panels, thus impacting long-term lifetime and maintenance costs.

When it comes to following specifications during the design and construction process, strict is good from the owner’s perspective. If the Owner’s Engineer rigorously enforces the specifications from the start, it sets the tone and expectations for the rest of the construction process and is likely to result in better project outcomes and fewer issues arising down the track.

Identifying safety issues and opportunities for improvement

An Owner’s Engineer brings a breadth of experience to a project as well as a clear pair of eyes and the ability to see the details as well as the bigger picture. The Owner’s Engineer is therefore well placed to identify potential safety issues and suggest improvements throughout design and construction. The Owner’s Engineer is involved in all stages of design, so is able to suggest safety improvements during safety-in-design and hazardous operations workshops. This can improve the chances of having issues of construction sequencing, construction safety or operational safety issues raised early in the design stages.

Construction inspections are often undertaken by a regular team member as well as a range of specialists. The regular team member creates continuity and the ability to compare practices on site over time. The targeted inspections by specialists focus fresh eyes on any potential issues arising during key milestones of construction.

Bringing a unique perspective

In our experience, the Owner’s Engineer can play a very valuable role in any project: helping to minimise risks such as construction delays and difficulties and maximise opportunities to achieve ‘best for project’ outcomes. The Owner’s Engineer brings a unique perspective: the ability to see a project from all angles, to maintain an independent view, and to filter everything through the lens of experience.

At Entura, we’re privileged to work with specialists who have been involved in both the design and operation of many power and water assets across their careers. They have worked with assets over the full lifecycle, so their insights stem from deep real-world experience. This ‘owner-operator’ perspective is not common among consultants, and we’re proud to apply it to help our clients get the best from their projects.

If you would like to discuss how Entura can help you with your renewable energy project, please contact us.

About the authors

Kate Hammerton is a Renewable Energy Engineer with a passion for hybrid energy systems and isolated micro-grids. She is involved in managing multi-disciplinary teams as the Owner’s Engineer on utility-scale renewable energy construction projects across Australia and the Indo-Pacific region, including the Agnew Hybrid Renewable Project, the Rottnest Island Water and Renewable Energy Nexus Project (WREN), Antarctica New Zealand’s Scott Base redevelopment at Ross Island, Tasmania’s Cattle Hill and Granville Harbour wind farms, and implementation of 14 MW of battery systems in Tonga.

Andrew Wright is a Specialist Renewable Energy Engineer at Entura. He has more than 15 years of experience in the renewable energy sector spanning resource assessment, site identification, equipment selection (wind and solar), development of technical documentation and contractual agreements, operational assessments and owner’s/lender’s engineering services. He has an in-depth understanding of the energy industry in Australia, while his international consulting experience includes New Zealand, Antarctica, China, India, Bhutan, Sri Lanka, the Philippines and Micronesia.


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.


Making progress in the field, despite pandemic challenges

While some aspects of fieldwork can be modified through technological innovation, there are other things that simply can’t be done without getting out on the ground or in the water. How can we make fieldwork not only efficient and effective, but also COVID-safe?

photo by Grace Uziallo

photo by Grace Uziallo

For our Environment and Planning team, interstate and intra-state travel restrictions and work-from-home orders rolled in at the height of the field season when most summer and autumn seasonal surveys were being completed and when many in the team would usually spend multiple days each week in the field. We’ve managed the fieldwork challenges through practical modifications for greater safety, taking confounding factors into account when analysing our results, using technology to support fieldwork, and collaborating with our clients, partners and local businesses to find solutions together.

Practical modifications for safety and wellbeing

Despite the restrictions and changed conditions brought about by COVID-19, we have been keen to find safe solutions to continue working seamlessly with our clients. Our teams have adapted their fieldwork patterns and adopted stringent methods, including fieldwork procedure reviews, undertaking day trips rather than longer trips where possible, reducing the number of people per field trip to the practical minimum, maintaining social distancing, and practising good hygiene, such as wiping down equipment and common touchpoints, from car gear sticks to the helms of our boats.

For example, our aquatic scientists are braving the Tasmanian winter chill to ensure that water quality and monitoring datasets for Hydro Tasmania continue to be logged. This data is critical to understanding impacts on aquatic fauna, and forms part of a multi-year monitoring regime for many of the state’s water bodies. The team would normally be undertaking week-long field trips; however, in response to the pandemic and due to the temporary closure of many accommodation options, the trips are shorter and efforts have been made to avoid the virus hotspots within the state wherever possible.

Managing fatigue is always important when undertaking field work, and especially so during COVID-19. For most field work, physical distancing requirements have ruled out travelling in a single vehicle. However, travelling in separate cars means that the driving can’t be shared. To manage fatigue associated with driving, we have made field days shorter, or, if more practical, we’ve stayed overnight in local self-contained accommodation to avoid travelling after long working days. 

Mental wellbeing has also been a crucial consideration while living and working through the pandemic. Our teams have stayed connected, whether working at home or in the field, through more virtual team catch-ups, quiz nights and virtual Friday post-work-week banters. Picking up on cues that indicate someone may be struggling is more difficult over email or a phone or video call than when working together in the office, so it’s more important than ever to actively check in on each others’ and our own wellbeing. At Entura, ensuring staff mental and physical wellbeing is always a high priority – and, particularly during the pandemic, taking time out to breathe and declutter the mind has helped us avoid mental burnouts and kept us as motivated as ever to deliver outcomes for our clients.

Taking confounding factors into account

Our ecologists have continued to undertake their monitoring programs, including night-time roadkill surveys along lengthy stretches of winding wilderness roads to look for threatened fauna such as quolls, Tasmanian devils and wombats. One of the challenges of undertaking this work during the pandemic has been the potential that the data collected may be confounded by reduced traffic volumes, making it questionable as to whether the data collected can be applied to a post-COVID world. In addition, reduced traffic volumes may also be influencing wildlife habits – for example, making them less wary of roads.

When interpreting the data, we took these potential implications into consideration, and some monitoring regimes were extended to compensate for potential changes to usual patterns. This will help ensure that the monitoring program provides a realistic representation of trends from which ongoing management decisions can be made.

Minimising fieldwork through technology

Entura has been actively assisting with Hydro Tasmania’s Battery of the Nation initiative. This initiative, jointly supported by the federal government (through the Australian Renewable Energy Agency) and state government, is investigating and developing a pathway of future development opportunities in hydropower system expansion including pumped hydro. For our Environment and Planning team and our Spatial and Data Services team, fieldwork for their involvement in Battery of the Nation has been able to continue, albeit with some innovative adaptations.

The spatial team has developed robust methods for visual impact analysis that can be applied to multiple project locations and types. To meet COVID-19 fieldwork guidelines, minimal staff have ventured into the field. These smaller teams have used technology to send real-time information (such as geo-tagged photos) to a pre-arranged server, allowing others at the ‘office’ to access the information almost immediately. The data has included light detection and ranging data, 3D models of project elements and real-life photography, which has been processed to generate 3D walkthroughs and web-scenes. These provide an important output for the project, but are also a useful tool for other team members to understand the site context without needing to go into the field themselves.

Solving problems through local collaborations

In some cases, overcoming the fieldwork limitations of COVID-19 has required a higher than usual level of collaboration with clients, partners and other organisations. For example, when the pandemic travel restrictions prevented the original interstate consultant from travelling to Tasmania as planned, our surveyors and ecologists were called in to assist our local partner TasNetworks with an important project on Bruny Island in Southern Tasmania. The submarine cable from mainland Tasmania that ensures security of electricity supply for the Bruny community is currently being replaced after the existing cable was damaged beyond repair late last year. Our proximity made it possible to step in to help. In a display of local collaboration, Entura assisted with the bathymetric and cable trenching clearance surveys, passing the data on to TasNetworks’ cable design engineers so that planning for replacement of the cable could continue.

Anticipating the ‘next normal’

In Tasmania, we are fortunate to be gradually emerging from COVID-19 isolation and we are eagerly awaiting the return of our ability to undertake the works and visits we have had to delay, yet we’re well aware that some changes or restrictions may be with us for quite some time yet. For now, we will keep working closely with our clients to be agile and resilient, so that together we can find safe and innovative COVID-friendly ways to move our projects forward.

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

For more articles from our Environmental and Planning team, visit our Thought Leadership collection, where you’ll find their articles about maintaining the progress of international projects and the challenges of starting new projects during the pandemic and the changes it has brought to planning regimes around Australia – amongst many more articles of interest to anyone involved in the power and water sector.


New circumstances, new projects, new regulations

It’s a major challenge to keep an existing local project running during these tricky times (let alone an interstate or international project!), but how can we start new projects as the ground shifts around us and as regulations around Australia change?


In this third article from Entura’s environment and planning team, we feature a recent win in the national water infrastructure space – the detailed design, and planning and environmental approvals for a new off-creek storage in the Northern Tablelands of New South Wales. And we take a look at how regulatory changes are playing out around Australia to provide greater flexibility to respond to current constraints.

Starting a new project during a pandemic

Entura, working together with Hunter H2O, is now assisting Walcha Council with a regionally significant project despite COVID-19. The township of Walcha is currently serviced by one small off-creek water storage, which means that stringent water restrictions are needed during periods of drought. The regional council, supported by federal government funding, is investing in improving Walcha’s water reliability and security, which will also deliver social benefits to the community.

Our team tendered successfully when COVID-19 was yet to hit our shores, but in a mere few weeks we found ourselves loading up our office gear to set up from home. The same week that our engineering, planning and environmental specialists were scheduled to fly to Walcha to meet with Council on site, travel restrictions intensified and flying out of Tasmania was no longer an option. We adapted by taking to virtual platforms to communicate with our client about the challenges imposed by COVID-19 and how we could still keep the project moving, albeit with some deviations from the original schedule.

As a multidisciplinary firm capable of working across many jurisdictions, we pride ourselves on the relationships we have established with local contractors. In these times we are even more aware of the benefit of these associations to help keep the work flowing. For this project, collaboration with local contractors and swift adaptation has allowed the team to keep the project moving forward. Local geotechnical contractors have begun their investigations to feed information to our teams. Meanwhile, our environmental and planning experts have studied databases and existing literature to determine potential terrestrial, aquatic and regulatory constraints that may affect the design of the new off-creek storage.

Lockdown restrictions are starting to ease across the nation, but for now we are sitting tight and waiting until it is safe to visit the site. We need to ensure that storage design works are undertaken only when our technical specialists have stepped foot on the site themselves and have a thorough understanding of the site context. In the meantime, we continue to provide value through virtual meetings and workshops with our client. Hunter H2O and Walcha Council share our view regarding both the safety of our people and the quality of design required for the project.

On this constantly shifting ground, we are keeping the regulators up to date with the progress of the project, and we are also ensuring we keep up to date with any regulatory changes which may affect the project and that these are well-communicated with our client.

Regulatory changes for flexible responses

Across the country, state governments are establishing new measures to accelerate projects to shovel-readiness to help buffer the social and economic impacts of the pandemic. They’re also making temporary orders to existing legislation to provide flexible planning and environmental responses.

New South Wales

In New South Wales, the Planning System Acceleration Program has been introduced to fast-track State Significant Developments, rezonings and development applications, as well as provide support to decision-makers to speed up local and regionally significant projects to approval. Temporary orders have been implemented to allow some infrastructure construction work to be carried out on weekends to maintain productivity and employment in the sector. In NSW, temporary changes to the Environmental Protection and Assessment Act 1979 (EP&A Act) allows the Minister for Planning and Public Spaces to authorise development to be carried out on land without any approval under the EP&A Act where that development is required to protect the health, safety and welfare of the public during the COVID-19 pandemic.

Other recent legislative change in NSW is the long-awaited amendment of the NSW Bilateral Agreement under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (Cmwth), which was required after the introduction of the new Biodiversity Conservation Act 2016 (NSW). This updated bilateral agreement has allowed environmental assessments and offsets to be streamlined, including endorsement of the NSW Biodiversity Offsets Scheme for the purposes of offsetting for a Commonwealth approval.

Queensland and Western Australia

In Queensland, COVID-19 has been declared an applicable event under planning legislation, thus allowing the Planning Minister more flexibility to suspend or extend any statutory timeframe across the planning framework if required. Similarly, in Western Australia, the Minister for Planning has issued a two-year extension for all current development approvals to assist job-creating projects during the recovery stage, along with other exemptions from planning approval for essential local community services.


The Victorian Government has announced temporary measures to make sure that planning and approval processes can continue to function despite remote working arrangements, including allowing local government planning authorities to make decisions under delegation to facilitate efficient application turnaround times. The Victorian Government has also established the Building Victoria’s Recovery Taskforce to explore planning and investment opportunities to boost the development industry. Additionally, the new Victorian Environment Protection Amendment Act 2018 (EPA Act), which is relevant to many infrastructure projects, was to take effect from 1 July 2020 but has been deferred until July 2021 to ensure developers, consultants and regulators have time to adapt to changes in workload and workflow as a result of the pandemic.


Tasmanian planning reform continues with the exhibition and assessment of local planning schedules as part of the transition to a statewide planning scheme. Consultation has also concluded on the proposed process for major projects, which, if enacted, will be the state’s first multi-permit approval process.


The Commonwealth Environment Protection and Biodiversity Conservation Act 1999 is also currently being reviewed, and our planning and environmental consultants are ensuring that they keep pace with the impending changes and implications for ongoing and new projects.

Managing change

For the Walcha project, the approval process is comparatively simple and the changes to approval processes are not likely to impact the project. However, for some of our other projects, these changes create challenges. Most notably, physical distancing requirements have meant temporary shutting of council offices and town information centres where application documents and technical studies are usually displayed. Instead, full suites of application documentation are being published online or, when specifically required, hardcopies are being mailed out. With postal services already under pressure, one way to ensure the community has a fair opportunity to provide feedback is to lengthen comment and consultation timeframes.

Although the global pandemic may have been disruptive to our work arrangements, smart and innovative ways to juggle project commitments and changed circumstances have fostered strong relationships which will persist beyond COVID-19. Elevated levels of trust and virtual teamwork with clients will surely present more opportunities to collaborate once the ground settles and we reach a new equilibrium.

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


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


What’s the best technology for your pumped hydro project?

For your pumped hydro project to be suited to future energy market conditions, you need to understand the technology options available – because pumped hydro plant is not one-size-fits-all. Let’s go for a deep dive …


Pumped hydro has been around for more than a century, but in recent years it has leapt into the forefront of the quest for energy storage and firming options as the energy sector embraces increasing levels of renewable energy generation. If you want to get the best from a pumped hydro project, it’s important to come to grips with the implications of the different types and combinations of mechanical and electrical machines that have been developed over the long history of hydropower and pumped hydro.

The choices are among fixed-speed reversible pump turbines, variable-speed reversible units (including doubly-fed inverter arrangement), and ternary sets. Each has its own variations and strengths in terms of the services able to be provided to the energy market. But the technologies also vary in costs, housing requirements and performance.

All pumped hydro projects are likely to offer benefits to the market by contributing to operating reserves, reducing spill or curtailment of variable renewable energy, reducing cycling and ramping of thermal plant, lowering transmission congestion and associated costs, and lowering greenhouse gas and pollutant emissions when used to displace thermal generation. But let’s look at the specific pros and cons of each of the different pumped hydro configurations, and how they compare.

Reversible units

Reversible units comprise a single hydraulic machine (turbine-pump), a single electrical machine (motor-generator) and a single shaft. The unit changes rotational direction to switch between generating and pumping modes.

These reversible units come in two different forms: fixed speed and variable speed. The fixed-speed reversible units can’t optimise the uptake of power from the grid in pumping mode, which is important in a grid with the rapid and frequent fluctuations characteristic of high levels of variable renewable energy. However, with a multi-unit arrangement in a power station, additional flexibility during the pumping cycle could be achieved at a premium.

Variable-speed reversible units provide greater efficiency and flexibility and provide different opportunities for grid support than fixed-speed units in pumping mode. However, should all the thermal plants be retired as the energy market transforms, the lack of synchronous machines could become a major issue where rotating inertia becomes scarce. Asynchronous (variable-speed) machines rely on their power electronic controls to provide inertia. While this can be artificially enhanced relative to synchronous machines, it relies on externally provided system strength which may also be lacking in the absence of thermal units.

Based on recent projects in Australia, the cost of electrical and mechanical equipment for variable-speed reversible units is about 30% greater than for fixed-speed units and the construction cost is approximately 10% more. Yet, while fixed-speed units come at a lower cost, variable-speed machines have the potential under some configurations to provide more valuable services in operation, such as variable load during pumping operation, and as long as there is adequate synchronous generation, inertia distributed around the network.

Ternary sets

Ternary sets comprise two hydraulic machines (a turbine and a pump), coupled on a single shaft, with a single electrical machine (motor-generator). This means that the direction of the turbine is the same in generating and pumping mode. They are often the only solution for projects with very high head but they can be applied for lower head projects too. Without having to change direction, little changeover time is needed between modes, making it possible to respond much faster to the grid. There’s also less stress on the machines, which can be individually optimised. The turbine and pump can even operate simultaneously (in hydraulic short-circuit mode), and the turbine can be used to start the pump (further reducing changeover time).

This description makes it sound as if ternary sets are the way to go … but it isn’t that simple.

Many of the elements of the civil works for a pumped storage project are the same whether fixed-speed reversible units, variable-speed reversible units or ternary sets are used. However, the powerhouse structure for ternary sets needs to be taller or wider (as the units are bigger), penstocks and tailrace branch pipes will require an extra bifurcation, and it is likely that the costs involved in hydro-mechanical equipment such as gates and valves will be significantly greater. 

The extra construction costs can add up to approximately 25 per cent more than for reversible units. And the additional electro-mechanical equipment could come at a 35 to 50 per cent higher price tag compared to the fixed-speed reversible units. However, countering the increased cost of ternary sets is their likely efficiency gain of 2 to 3 per cent and a faster response time than reversible units are capable of.

The increasing need for fast response

Adopting either variable-speed reversible units or ternary sets appears, on the face of it, to be more expensive than fixed-speed reversible units, but there are mitigating circumstances that make them worthy of serious consideration.

With settlement periods in the Australian National Electricity Market reducing from 30 minutes to 5 minutes, fast response is critical. Both ternary sets and variable-speed reversible units have a big advantage over fixed-speed units in this regard, but fixed-speed units can work with the 5-minute settlement if they are utilised appropriately as part of a pumped storage scheme.

Short-circuit mode

Reversible units and ternary units require similar amounts of power from the grid in synchronous condenser mode. For a 125 MW unit, the grid power required is estimated at about 4 MW.

Some projects investigating the idea of hydraulic short-circuit with variable-speed, doubly-fed inverter machines are currently underway. In essence, a waterway is shared between two units with a bifurcation upstream and downstream of the units. In this case one of the units will operate in generating mode and the other in pumping mode.

What’s the answer?

There’s a lot to take in when comparing the different pumped hydro configurations. It’s generally accepted that variable-speed reversible units and ternary sets have certain advantages over fixed-speed reversible units in a changing energy market. Yet, in some cases fixed-speed units will do the job, and at a lower cost, whilst at the same time guaranteeing synchronous generation if rotating inertia is of essence to grid stability. There’s no clear-cut winner when it comes to pitting variable-speed reversible units and ternary sets against each other. As usual, the right choice will depend on the specifics of your project conditions and what changes you anticipate as energy markets continue to evolve.

If you would like to discuss how Entura can help you with your pumped hydro or renewable energy project, please contact Nick West on +61 408 952 315, Richard Herweynen on +61 429 705 127 or Phillip Ellerton on +61 439 010 172.

About the authors

Nick West is a civil engineer at Entura with more than 18 years of experience, primarily in hydraulics and hydropower. Nick’s skills range from the technical analysis of the layout of hydropower projects to the preparation of contractual project documents and computational hydraulic modelling. Nick was a key team member of the Kidston Pumped Storage Project Technical Feasibility Study and is currently involved in feasibility assessments of pumped hydro options as part of Tasmania’s Battery of the Nation initiative.


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.


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. 


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.


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.


Becoming the Battery of the Nation

This article appeared first on the International Hydropower Association blog.

How can a small island become a giant battery for a nation? We’re finding the answers in increasing interconnection, developing new pumped hydro and repurposing our existing hydropower assets.

Tasmania is a small island state, with excellent water and wind resources. We’re powered mostly by an extensive hydropower system developed over the last hundred years – supplemented with newer wind developments. We’re connected to Australia’s National Electricity Market by an interconnector running across Bass Strait to the mainland. This has allowed us to trade in the national market for some time now, but as thermal generation progressively retires and Australia embraces greater proportions of variable renewables, the future national market will be vastly different. It will be characterised by low-cost variable renewable energy sources firmed by dispatchable storage and generation.

With Tasmania’s fantastic natural resources, established hydropower system and expertise, we want to be the ‘Battery of the Nation’, offering the generation and the storage and system support needed to help Australia achieve a clean, reliable, affordable energy future. Our Battery of the Nation vision is shaping up to be one of the most credible, competitive and coordinated solutions, able to be built in stages, aligned to market drivers.

In a nutshell, the Battery of the Nation means generating more renewable energy from our hydropower and wind assets, developing more storage solutions in the form of pumped hydro and building more interconnection to the mainland so that we can get our product to the national market to quickly and reliably support variable generation. 

With the support of funding from the Australian Renewable Energy Agency (ARENA), we’ve been making progress towards this vision on a number of fronts.

Connecting the battery

Batteries aren’t much use if they’re not connected, so we need more interconnection to mainland Australia to get the power to where it’s needed. The initial business case for a new, second interconnector between Tasmania and mainland Australia shows it stacks up, and federal funding has recently been secured to fast track this 1200 MW interconnection project, known as Marinus Link.

Priming the pump

Around the world, significant investment is being made in new technologies such as grid-scale batteries and solar thermal projects, yet pumped hydro remains the most viable technology for longer term storage (greater than eight hours). Our state has significant pumped hydro potential and our existing hydropower assets offer excellent potential to repurpose and create cost-effective pumped hydro. We’re filtering down the possible pumped hydro options to identify around 2500 MW of future potential. The three most promising sites offer between 12 and 31 hours of storage and would cost around AUD 1.5 million / MW to develop. Further feasibility investigations will identify which one of these three will be the preferred option that can be ready to take advantage of more interconnection.

Redeveloping existing assets

We are also focusing on how to get the most out of our existing hydropower assets by repurposing and futureproofing them for a transitioning electricity market. The Tarraleah scheme in Tasmania’s central highlands was commissioned in the 1930s and our studies have been considering whether the scheme should be progressively refurbished or redeveloped. Redevelopment would more than double the scheme’s capacity from 104 MW to up to 220 MW – contributing to Battery of the Nation targets. By converting the station to flexible and fully dispatchable operation, instead of just baseload, it could flexibly boost output at times of high market demand and provide the ancillary services likely to be increasingly valued in the market. It is also expected to have flow-on benefits for the entire cascade of power stations below it.

We are also continuing major refurbishment and upgrades of other existing hydropower assets so that we can get more generation, efficiency and longevity from these assets to support our plan to become the Battery of the Nation.

Benefits for our island and the nation

The Battery of the Nation vision offers economies of scale and diversity by combining flexible, reliable renewable energy resources with cost-competitive, large-scale storage that can be built in stages, aligned to market drivers. 

Battery of the Nation is designed to serve and support our local and national communities. Across the nation it will contribute to achieving lower power prices, reliable and secure energy supply, and meeting sustainability targets. It will also offer specific benefits to Tasmania through energy security and economic stimulus.

Battery of the Nation is a bold and bright vision to unlock our potential to contribute to the nation. It’s an example of how to reimagine hydropower and storage for the new market paradigms of a shifting energy future.

Can the power grid weather the weather?

Even a single day of load shedding makes people doubt the national grid’s robustness. How will the grid cope if we experience extreme weather conditions more often?


Things get hot in Australia. They can get smoky, or wet, or cold. Australia’s beauty is in its ruggedness, its unpredictability and its diversity of natural environments. It’s what Dorothea Mackellar captured so well in the famous Australian poem ‘My Country’ – a ‘sunburnt’ land of ‘flood and fire and famine’, with ‘droughts and flooding rains’.

As dramatic weather patterns become more intense and more frequent, the electricity grid must be robust, or at least be managed to adapt to short-term challenges.  

If we get the design standards right and if conditions fall within the expected extremes contemplated by the framers of the standard, then everything works. However, what happens when conditions are abnormal? In heatwaves, we see people hosing the rail network to stop expansion. We’ve seen hosing to cool distribution power transformers at peak times too. But there’s only so much water and so many hoses that we can deploy when the heat is on. It’s not a sustainable solution.  

Can we manage?

Yes … but we must manage actively. Business as usual will not be enough. Consumers will not tolerate lower levels of reliability based on the weather. So something has to change.

There are a few mutually supporting paths we could take, including (1) considering extreme temperature ratings and improving the reach and spread of weather monitoring and weather-dependent grid management; (2) adjusting standards to contemplate higher temperatures; and (3) reducing our reliance on high flows to deliver peak demand.

1.  Consider extreme temperature ratings

Incentives already exist for our network service providers (NSPs) to release hidden capacity in networks. The incentives remain a small percentage of the overall regulated income they receive. The contemplation and control of realistic ratings under unusual weather conditions could be made more attractive to our NSPs. The NSPs would then be more likely to make these opportunities for capacity benefits transparent to the regulator and the public.

Generators are now being required to stipulate capacity at higher temperatures, but this is not being applied universally across existing plant. As we saw in Victoria this summer, the market is very reactive to the unplanned withdrawal of power from large thermal units – as much, if not more, than it is to variations in wind and solar power. Thermal machines have shown themselves to be sensitive and not always robust in prolonged hot spells.

2.  Change the standards

If maximum temperatures continue to climb, our standards or ratings may need to be adjusted to suit. In a global market, we have to be careful about being too ‘special’ or we’ll end up paying for specifications that cost more than the benefits they deliver. A half-way position may be for generators to estimate their capacity in relation to temperature conditions and require tuning of these estimates over time. This would at least give us an idea of the temperature effects on production across the fleet. The results of this might then inform the need for changes to standards or at least build quality to relieve unmanageable reductions.

3.  Reduce reliance on high flows

We’ve seen the effect that emergency events such as storms and fire have on the grid. Storms are managed through localised declarations of special constraint sets. They’re also generally short-lived. As we saw with the Tasmanian bushfires this summer, smoke and fire can affect a transmission corridor for weeks at a time. Because intense storms and fires tend to be rare, the market can take some time to adapt. Some planning or scenario work by AEMO might help prepare the market and reduce the impact on supply.  

Reducing our reliance on high flows to regulate price or maintain supply may also be valuable. This suggests a need for storage/s at opposite ends of tie lines and interconnectors so that short periods of constrained flow can be compensated partially or fully by the far-end storage.

We may also need some flow-path diversity on critical corridors or on corridors that link dispatchable generation sources with loads.

There’s little doubt that Australia will experience more frequent and intense floods, fires and heatwaves. In our ‘sunburnt country’ we need to keep our eyes firmly on the future of our climate, and we must build resilience into our generators, grid and market systems.

If you would like to find out more about how Entura can help you navigate your challenges in the electricity market, 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.


Powering up the Pacific with hybrid renewables

Beyond the typical images of blue water, white sand and sunny days, many Pacific islands are becoming visions of renewable energy innovation.


For remote off-grid communities with abundant sun and wind, such as Pacific islands, hybrid renewable energy systems offer exciting potential for achieving sustainable, secure and affordable power supply. Governments and utilities across the Pacific are embracing opportunities to harness the power of nature and lessen reliance on expensive and emissions-intensive diesel fuel.

At first glance, this picture looks perfect. But it isn’t simple. Off the grid, the impact of the intermittent nature of renewable energy is magnified. As the proportion of renewable energy in the power system increases, so does the need for enabling and supportive technologies to stabilise the power system while maximising the use of the sun and wind. This calls for innovation and integration.

A leading example of an advanced hybrid renewable power system has been completed on Yap, in the Federated States of Micronesia. It’s an inspiring example of innovative deployment of hybrid renewables to increase the energy security and sustainability of an off-grid island.

Yap, like many remote and small island states, will benefit from a clean energy power system for three main reasons: to reduce heavy reliance on imported fossil fuels, to stimulate economic growth and social development, and to improve resilience during increasingly frequent and severe storm events.

After decades of operating on diesel fuel only, Yap’s advanced hybrid renewable energy system is now enabling Yap to experience up to 70% instantaneous renewable penetration when conditions allow, with an average renewable contribution of 17%. It is delivering an annual fuel saving of up to US$500 000, and is designed to accommodate even more renewable energy generation into the future.


The journey towards a hybrid renewable energy system

Back in 2014, with funding from the Asian Development Bank and the World Bank, Entura helped the Yap State Public Service Corporation take early steps on a renewable energy journey. Like many small island nations on the frontline of climate change, and facing the damage of shrinking coastlines and the ravages of tropical storms, Yap recognised the value of renewables in reducing diesel consumption, increasing resilience and economic viability, and offering lasting benefits to its community and environment.

The first stage of the process was determining the most appropriate hybrid diesel/renewable power system that would displace the greatest amount of diesel fuel within the project’s budget and transform the manually operated 100% diesel power station into a flexible, integrated and automated power system incorporating wind, solar and diesel generation.

The power system was designed to meet the 2.2 MW load for the approximately 7000 people living on the main island, delivering up to 825kW of wind energy from small but robust wind turbines and 300 kW of remotely controlled grid-connected solar energy from the rooftops of seven government buildings.

Entura provided owner’s engineer services on site during construction and commissioning. In this stage, a new breed of high-renewable-supporting diesel generators were installed, and major works were carried out to install three 275 kW cyclone-proof wind turbines. As well, an island-wide communications network was installed, providing vital interconnection for the distributed solar PV and the wind turbines. This stage of the project also brought in the ‘brains’ of the system: a centralised control system.

The overall architecture of Yap’s integrated renewable energy system, combined with the innovative automated integration and control system, balances and maintains the security of the energy supply, and also maximises the amount of renewable energy used on the island.

A future focus

With a strong focus on the future, the communications network and control system are designed to accommodate further integration of more renewable energy generation as required or desired. Entura is investigating the feasibility of including even more diversified, distributed, variable renewable energy generation to be incorporated into this system, including up to an extra 1.6 MW of ground-mounted solar, 1 MW of floating solar, 300 kW of roof-mounted solar, a 1.5 MW battery energy system, as well as the potential for another 825 kW of wind power (depending on land-owner negotiations).


As well as being designed to be able to realise future goals of operating at zero diesel, Yap’s power system is also intended to be able to be operated and maintained within the community rather than by external specialists. The Yap State Public Service Corporation and Entura are working together to develop capacity within the Yap community, so that the local people will not only own the new state-of-the-art energy system, but will also have the opportunity to develop the skills needed to operate and maintain it into the future. Local power authority crews are now fully competent in solar system installation and maintenance, and have installed all the solar components of the scheme.

For Yap, access to reliable, affordable and sustainable modern energy is an important step towards lasting social and economic benefits for the local community, as well as better protection of the beautiful but fragile natural environment.

This example of effectively integrating existing and new technologies to create a secure clean energy system is at the forefront of world’s best practice. The success of the project has obvious application for remote, off-grid or island communities worldwide – but the strength of the technologies and their integration and control are equally applicable to the creation of ‘dispatchable’ renewables at any scale.


If you would like to discuss how Entura can support your journey towards hybrid or dispatchable renewables, please contact Patrick Pease or Shekhar Prince on +61 412 402 110.


Safer dams are a matter of priority

Examples from around the world demonstrate the devastating consequences of dam failures. Safety must be every dam owner’s key concern, but how should action be prioritised across a large portfolio of dams?


To prioritise effort and resources to achieve the best safety result across a whole portfolio of dams, you need a portfolio risk assessment (PRA). A PRA determines the risk position of the dams based on known information, identifies any information gaps, develops a strategy to close these gaps, and then determines the most effective actions to decrease any risks.


Entura has supported dam owners and water managers across the Indo-Pacific region with PRAs, but our most extensive application of the PRA process has involved the 54 large dams of our parent company, Hydro Tasmania.

Hydro Tasmania is Australia’s largest water manager and is committed to ensuring that the risk of a dam failure is very, very low across the entire portfolio. Across so many dams, clear priorities are needed to focus dam safety efforts and human and financial resources.

It has now been 20 years since Hydro Tasmania’s PRA journey began in 1999, so it’s timely to reflect on its outcomes.

With so many dams of greatly varying types, ages and heights, the PRA across Hydro Tasmania’s dams was always going to be complex, and needed to be staged. The first step was a small pilot study on five selected dams that represented the range of potential risks within the broader portfolio.

During the pilot study, the five steps of Entura’s PRA process were defined: 
5618-Entura_Dam Safety Infographic-02

This methodology was applied across Hydro Tasmania’s dams portfolio, and an average of eight dams were added to the review each year.

By 2005, the initial ‘baseline’ assessment of the full portfolio was complete. The focus of the dam safety program has now moved to investigation and implementation of upgrades, and the communication of outcomes to senior management.

The PRA process has increased the focus on potential failure modes and risk as drivers of the dam safety program and as the basis for deciding priorities for allocating operational and capital resources.


Entura’s PRA process reviews the consequences of failure of a dam by looking at the impact that it may have on downstream populations and infrastructure. The engineering assessment considers the effects on dams of extreme events such as floods and earthquakes, taking into account the specific site conditions. Combining the chance of failure and the resulting consequence determines the level of risk.

Hydro Tasmania assesses, prioritises and mitigates risks across the business using an integrated business risk management program, and the dam PRA feeds into this overall risk management approach. A dam’s assessed risk rating across common tolerance criteria drives the risk management response. The assessed dam risks are plotted together on a chart to provide a risk profile for the whole portfolio. This allows dam safety risks to be compared, understood and communicated readily throughout the business in a similar way to all other business risks.

The initial objective of the dam safety program is to reduce all the risks categorised as ‘high’ or ‘extreme’ as soon as practical , and then to continue with a program of investigations and capital works to diminish risks even further. Actions for dams lying in the higher risk zones did not wait for completion of the PRA, but were initiated as soon as risks were identified.

Some cost-effective and expedient risk-mitigation was achieved by identifying and implementing ‘quick wins’. These early actions reduced the overall portfolio risk while more complex mitigation plans were being developed. In some cases the ‘quick win’ actions have even provided the ultimate solution. In other cases, more major works have been required.


The PRA process has substantially benefited Hydro Tasmania’s dam safety program, by improving understanding of the dam portfolio, underpinning a strong strategic plan for addressing risks, improving surveillance and monitoring, and considerably strengthening dam safety emergency planning and warning.

However, this isn’t the end of the dam safety journey. Knowledge of any dam is never complete, and it is critical for dam owners to remain aware that not every failure mode may necessarily have been identified in a baseline study that relies on existing information. There may still be a level of uncertainty about the ‘unknowns’.

For Hydro Tasmania’s PRA, identifying these uncertainties enabled development of a prioritised list of investigations necessary across the portfolio. These detailed investigations have been critical to the development of the dam safety program, by confirming any potential failure modes identified in the PRA.

The list of potential failure modes of a dam portfolio must be rigorously and regularly reviewed, and investigations to reduce uncertainty about the portfolio should be ongoing. New methods and techniques for analysis are being developed all the time, and it is important to understand how these may change existing risk assessments. As well, the safety and risk-level of a dam can change as dams age, or when there are changes to the way the dam is managed.

It is also important to realise that the capital works program for dam safety risk reduction across a portfolio must remain flexible and be actively managed to respond to new or changed risks, new developments in the field of dam engineering, shifts in business priorities, delays to projects, and new developments in risk management.

The sheer number and variety of types, ages and consequence categories of Hydro Tasmania’s dams made Hydro Tasmania’s PRA a challenging process, but the benefits are substantial. The baseline study completed in 2005 is not the end of this journey, which continues to prioritise actions, reduce risks and enhance safety across the portfolio. 

If you would like to discuss how we can assist you with assessing your dam risks, developing a resource-effective and comprehensive dam safety program, or applying the same PRA process to other key assets, please contact Paul Southcott, Richard Herweynen or Phillip Ellerton.

About the author

Paul Southcott is a specialist civil engineer at Entura. He has more than 32 years of professional expertise in civil and dam engineering, as well as expertise in geotechnical, foundation, structural, hydraulic and hydropower engineering. Paul’s dam engineering experience spans geotechnical and hydrological investigation; feasibility and options studies; concept, preliminary and detailed design; engineering assessment, consequence assessment and risk assessment; safety reviews; monitoring and surveillance; and emergency planning. He has extensive experience in dam risk assessment including as project manager for Hydro Tasmania’s, Taswater’s and SAWater’s portfolio risk assessment projects.  He was a member of the ANCOLD committee that issued the Guideline on Consequence Categories for Dams in 2012 and is currently a member of the ANCOLD committee drafting the new Guideline on Geotechnical Investigations for Dams.


Should you upgrade or replace your SCADA system – which option is best?

New functionality, increased visibility of plant, greater security … SCADA systems are rapidly advancing. So, should you stick with what you have, upgrade some components, or embrace a complete replacement?


This is an important and complex question for power and water owners, operators and utilities to consider. As SCADA systems become obsolete, outdated or unsupported, a range of risks come into play – so you need to carefully weigh up your options in terms of benefits and costs. Choosing the wrong system could affect your business operations or your future upgrade options.

The first step in your decision making must be to explore and understand the available SCADA options in the context of your business strategy. SCADA systems are too great an investment and too important for ad hoc or hasty decisions. This is the time for a clear-headed view of your business goals over the long term, and how your choice of action will support achieving the outcomes you seek.

In the context of this strategic view, you now need to objectively assess the value and relevance of your existing SCADA system and identify if the entire system needs to be replaced or whether some devices or software can be reused. Let’s look at ten key considerations in the decision:

1 System architecture: When you introduce new equipment or systems, your system architecture is likely to be affected. Changes to system architecture can affect the reliability or operation of your plant. A partial upgrade may or may not significantly affect the system architecture – it really depends on the changes made. The system architecture following a total system replacement may be dictated by the vendor you select, so keep this in mind when selecting vendors. Does this system suit your business or the vendor supplying it? Also make sure that your system architecture is thoroughly and accurately detailed, and keep your SCADA strategy in your back pocket for reference throughout your journey.  

2 Reliability: If parts of your existing SCADA system are reused, will this impact the reliability of the new system? Depending on the age and condition, there may be a greater risk of unreliability with the reuse or partial upgrade of components vs a complete replacement. The key here is to ensure the right people can evaluate the system and components with the knowledge of how to overcome these challenges. To minimise the likelihood of equipment failures and achieve the best outcome in terms of reliability, sometimes the best option is to carry out a full replacement.

3 Costs: A complete SCADA replacement is a costly exercise but at some point you can’t keep delaying a major outlay by only fixing the immediate concerns. Just like the increasing costs of servicing and replacing parts on an ageing car, at some point the ongoing incremental costs may no longer be worth it, and you may have to consider a total replacement. Regardless of the option you choose, having the expertise to make this call and carefully planning/estimating the work will reduce the risks of unexpected costs. The key decision-makers in your business will need to explore how to balance the initial outlay against the potential cost savings to be achieved through limiting the duration of system outages and attaining a longer whole-of-system life.

4 Functionality: The range of SCADA devices is extensive. A simple device may be cheap but it may not have been designed and built to meet high performance and reliability requirements, and it may not have the management functionality or redundancy capability you need. Your choice of functionality is partly a matter of initial cost, but you also need to carefully consider how much you need the extra functionality, what savings that functionality can offer over the longer term, your tolerance for failure, and the cost of failure to your business.

5 Compatibility and standardisation: When devices and software are upgraded or replaced, compatibility challenges and limitations may arise when interfacing with existing system components. Carefully assess your existing system and verify that the specifications and functionality of the proposed equipment are sufficient. Also consider the benefits of standardisation of system components. Standardising equipment throughout your site or sites can greatly speed up fault diagnosis, reduce design costs, minimise the need for more training, and lower your spares requirements.

6 Human interface: When your SCADA system upgrade includes the Human Machine Interface (HMI), identify which parts of your HMI screens work well and which don’t, and consider the option of designing your screens from the ground up. Avoid cluttered interfaces and consider dashboards for a single, easily interpreted overview of parts of your plant or station. If you’re changing your screen navigation and displays, you will need to allow for additional training to ensure your people are confident and capable of operating and monitoring the new system. Upgrading your HMI with a newer version of the software may be the best way forward depending on your requirements. This may require less financial outlay in terms of licensing, engineering and training costs and may be less intrusive on your system. If your system assessment warrants a complete replacement, you should carefully evaluate alternative HMI solutions to achieve the right functionality, product roadmap and financial outlay.

7 Security: How will upgrading parts of your SCADA system affect overall system security? SCADA security has evolved dramatically in recent years. Managing today’s SCADA systems can be a challenge without the right security precautions in place. Because SCADA system attacks exploit both cyber and physical vulnerabilities, it is critical to align cybersecurity measures accordingly. System security challenges of partial upgrades may not be able to be overcome depending on the age and type of equipment. So implementing a new system with the latest security technology is becoming the best option for limiting your exposure to attack.

8 Future-proofing: Just as you need to plan your pathway to implementation, you also need to keep your eyes on the future. If you’re upgrading old components, factor in the end-of-life date for support. If a device becomes obsolete, you’ll need a changeover plan to limit the impact on the system. Even if your upgrades give you the functionality you need now, what will you need in the future? Transitioning to a new SCADA system will introduce new functionality that is likely to increase the effectiveness of your operations and maintenance, and give you the opportunity to embrace the potential of big data, machine learning and artificial intelligence.

9 Pathway to implementation: Whatever the journey you’re on, you need to think about the path ahead so that you don’t encounter unexpected obstacles such as hidden costs or schedule blow-outs. Identify what upgrading may mean for your existing system and what limitations your system may have. Will your historical data need to be migrated to your new system, and, if so, how will this need to be handled? Upgrading to a new version of your SCADA system may be the easiest solution, but if you decide you need a new system, you’ll need to carefully handle your historical data and massage the data into the correct format for your new system.

10 Testing and commissioning: During the design process, contemplate how your system will be implemented and commissioned. Commissioning new equipment instead of reusing old technology may reduce the risk of incompatibilities and unusual operations. It may also reduce the time required for testing due to thorough system factory acceptance tests. Retesting of old equipment may have considerable impacts on your plant or station operations. The testing process and sequence is another key item that can make or break your system implementation. Assess how your system will behave during the cutover process and how the correct sequence or test process could reduce or eliminate your plant or station downtime.

Deciding whether to upgrade or completely replace your SCADA system is very much a case-by-case situation – but you’ll find the right solution if you consider all the key issues carefully and have your decision assessed by the right people and carried out objectively.

If you would like to discuss your SCADA challenges and opportunities, contact  James Devine on +61 417 389 713, Patrick Pease or Shekhar Prince on +61 412 402 110.

About the author

James Devine is Entura’s Specialist SCADA Engineer and has over sixteen years’ experience in SCADA and automation design, implementation, commissioning and project management. James has worked with clients both within Australia and overseas on a diverse range of systems including solar and wind farm SCADA systems, substation SCADA and automation systems, hydro and gas generation SCADA systems, water and wastewater SCADA systems, and wide-area SCADA and telemetry systems. James has considerable experience reviewing many clients’ existing systems and proposed designs, as well as providing specialist technical advice for single-site SCADA and automation systems through to wide-area SCADA systems and master stations.


Limber up for a more flexible electricity grid and market

Integrating renewables into grids and markets is a hot topic worldwide, with many challenges and approaches to explore.


In late June 2018, a series of meetings run by the International Energy Agency (IEA) in Yokohama, Japan, brought together a wide range of electricity industry regulators and participants to discuss the IEA’s current work in this arena. There was a lot of ground to cover. I shared the Tasmanian experience of managing frequency using inertia and governor tuning.

For me, three main takeaways from the discussions are that we need to improve Australia’s market arrangements, increase flexibility, and we should try to re-imagine the grid as an interaction.

Improving Australia’s market arrangements

Anyone who’s been watching the Australian electricity sector over the last few years will recognise that there’s room for improvement in our market arrangements.

The National Electricity Objective (NEO) aims to promote the long-term interests of electricity consumers through efficient investment in, and operation of, electricity services. These consumer interests include the price, quality, safety, reliability and security of supply of electricity. It also means ensuring the reliability, safety and security of the national electricity system. However, commercial and environmental drivers are beginning to affect the security of electricity, and in some instances affecting the price as well.

It’s hard to see why we’ve ended up where we are. What’s important is what we do next, and why.

Understanding and pursuing flexibility

All sources of generating plant have flexible and inflexible attributes. We have always worked around the limitations and taken advantage of the benefits. Now, with disruption, prosumers, micro-grids and all the other ‘scary’ status-quo-busters, we have much more freedom to achieve flexibility than we have had in the past. That is, generators, grids and customers can all provide flexibility and add to the overall value of the electricity market.

Designing new plant, retrofitting old plant and improving controls to increase flexibility must all form part of planning and regulation as we continue to decarbonise electricity production.

Imagining the grid as interaction, not assimilation

The philosophy of grid revolution to date has been assimilation. That is, where possible, new generators need to look and feel like traditional generators.

As system security margins decrease, this is becoming even more the case. It sets up a sometimes false dichotomy in terms of market share, political ideology, technical requirements and standards, and assessment of value. And this is unhelpful as we move towards an electricity sector with increasing proportions of renewables. One reason why Australia may have ended up where we are now may be that the NEO is silent on environmental impact.

When we think of the grid and the market as spaces for interaction rather than assimilation, these dichotomies break down and we’re more likely to achieve fruitful outcomes. Interactions are not just technical (electrons and Ohm’s law) or commercial (tariffs and hedges) but also human.

The electricity transformation will be able to occur faster and more successfully when the electricity industry embraces the power of the demand side, interacts in a more beneficial way with human-scale usage patterns and requirements, and thinks about the flexibility that exists or is required in demand, storage and production.

Finding a new approach

This all sounds marvellous, doesn’t it? It is the sort of regulatory utopia that could only come from a group of government officials sitting around a table a long way from home. But for me, it was refreshing. The thought that the market serves a higher ideal can only inspire. Certainly, the developing countries that presented at the meetings are firmly motivated by the immediate benefits and opportunities that reliable access to electricity will provide to their people. 

In some ways Australia, too, is a developing country in the electricity sector. In the status quo, the path to future sustainability is blocked by the threats of climate change and, in some respects, by resource scarcity (depending on your view of the horizon). We need to develop a new approach to electricity production and consumption just as developing countries do.

If we think of the market as a facilitator for humans to flourish, then we must be careful to design markets for this purpose. Is the Australian market hampered in this respect by the dominance of a limited number of large players? Is there sufficient direct participation of individuals in the market? Does the regulatory framework accurately and adequately reflect the needs of all market players? Does the market inherently promote and reward flexibility? 

Market power, democracy and flexibility

My feeling is that there’s work to do across each of these areas.

A former Australian trade minister once remarked that Australia would always be somewhat of an oligopoly. We will never have large-enough markets that won’t be dominated by a few players. In some sectors we’ve enshrined protections that almost guarantee it. The current market design has led the electricity sector down this path.

This is okay so long as the behaviour of these players remains able to be influenced by their customers through choice of provider and volume, but this isn’t always the case.

Allowing more players to provide greater diversity of energy and grid services will help to erode the power of the oligopoly and will also increase the flexibility of the grid and the market. Various system incidents in South Australia and the Northern Territory have highlighted the need for flexibility. If we understand flexibility properly, we will understand a way to meet the need for it.

Greater flexibility can mean different usage patterns, different contributions from a wider number of players and more give and take between the grid and the various generating technologies. Providing rewards for flexibility will encourage diverse contributions, slow the retirement of existing plant, and bring new players into the mix.

Markets, grids and power plants must be planned and will need to allow for greater flexibility to provide better outcomes for customers. It’s time for the electricity sector, its regulators and its customers to limber up.

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

This article was first published in RenewEconomy.

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.