Safer hydropower stations for safer workers

“Practices related to dam safety are well-defined and accepted throughout the world. However, hydropower safety encompasses more than just the dam … while hydropower safety is of critical importance, there is little shared knowledge on good practices around the concept of hydropower safety.” – International Hydropower Association

Hydropower stations can pose significant safety risks to those who work in them, but there is no excuse for injury or death in our workplaces. Whatever the history or location of the hydropower station, safe plant and safe work practices are critical.

Developers, owners and operators of hydro plant all need a strong commitment to workplace health and safety, and the insight and vigilance to control safety risks. As the saying goes, ‘safety doesn’t happen by accident’.

The hazards of hydropower stations

Some of the hazards at hydropower stations differ from those at thermal power stations or commercial installations. For example, hydro stations typically have limited access and no natural lighting, lower floors are often below the outside water level, and many are underground.

Hydropower hazards include fire, explosion (e.g. of pressure vessels), electrocution, flood, entanglement, slips and falls, chemicals (e.g. sulfur hexafluoride, hydrogen sulfide) and hazardous products (e.g. asbestos), and asphyxiation (e.g. carbon dioxide).

The level of risk presented by each hazard is a combination of its likelihood of occurring and the consequences if it did occur.

Seven ways to make a hydropower station a safer place

Designing safety into hydropower stations

When designing and implementing a new hydro scheme, or when upgrading an existing station, we need to carefully consider the standard of workplace health and safety to be achieved and the scope of work necessary to achieve it. This means understanding the relevant legislation, building codes and standards, and the requirements of the insurer; and being clear about the responsibilities of all the parties involved (such as the designer, developer, owner and contractors).

But while standards, codes and guides are a good starting point, the final solution needs to be tailored for the particular circumstances and level of risk. Safety systems for hydro plant can be complex and sophisticated, but they can also be as simple and robust as appropriate for the hydro facility being protected.

The primary consideration should be to provide safety facilities to get personnel out of a hydro station safely before conditions inside become dangerous. The second consideration should be providing facilities to get people out safely after conditions become dangerous. Only thirdly do we think about safety facilities to prevent damage to plant.

Planning ahead to control risks

A general approach taken to minimise workplace risks to the lowest practical level involves planning ahead for prevention of workplace accidents, injuries and illnesses, by ensuring that systems of work are safe, equipment is safe and properly maintained, and employees receive health and safety information and training and are properly supervised.

This approach is usually expressed through a ‘hierarchy of controls’:

Safety upgrades for older hydropower stations

Typically, new hydro stations are well designed and comply with appropriate safety standards and local building codes. Larger hydro stations can have safety systems as complex and thorough as those in modern multi-floor commercial buildings. However, older hydro installations were often designed with little regard to safety, and now need urgent attention to comply with modern workplace health and safety standards.

While safety facilities are readily incorporated into new hydropower schemes, they may be more difficult to retro-fit into existing schemes. The scope of work will need to take into account the interfaces with existing facilities and the tailoring required to suit the specific site and location.

Sharing our hydropower safety insights

Entura is part of Hydro Tasmania, Australia’s largest producer of renewable energy and manager of more than 30 hydropower stations with an enviable safety record. As a specialist power and water consulting firm, we’ve applied this real-world experience of designing safe hydropower stations and upgrading older plants to meet modern safety standards as we work with clients all over the world to improve the safety of their assets.

In our experience, these four very important aspects of hydropower safety should be considered as a first step towards building good practice for designing and operating safer hydropower stations:

To discuss how Entura can assist you with assessing hydropower station risks or developing a hydropower safety program, please contact Ambrose Canning on +61 3 6245 4212 or Shekhar Prince on +61 412 402 110.

About the author

Ambrose Canning is Entura’s Principal Consultant, Mechanical Engineering. He has more than 30 years’ experience working on hydropower and water infrastructure projects in Australia, New Zealand, Malaysia, Papua New Guinea, India, Nepal, Philippines and Indonesia. He specialises in all aspects of hydropower development and redevelopment, upgrade and rehabilitation. He also has expertise in aspects of water infrastructure, such as dam electro-mechanical and hydro-mechanical equipment, pipelines, valves, pumps, screens, gates, valves and bulkheads.

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Starting safe, staying safe: building safety into electrical design

Because electricity has inherent risks with serious consequences, safety should always be a fundamental concern of consultants and clients working with power assets at all stages of the project lifecycle.

We know that the safest and best outcomes are achieved by using a ‘safety in design’ process to ‘design safety in’ from the very start. As projects progress towards implementation, remedying risks becomes increasingly costly and progressively less effective, so it’s far better to get things right early on.

Safety applies to electrical design too

Giving greater and more systematic attention to eliminating safety hazards at the design stage emerged from the historically poor safety performance of the construction industry and is now well established.

Safety in design (SID) processes integrate hazard identification and risk assessment methods into the design of all aspects of a project to eliminate or minimise the risk of injury throughout the project or structure’s life (including decommissioning or disposal).

It is a common misconception that SID processes don’t apply to the electrical industry because we have ‘tried and true’ standardised designs that already comply with existing safe standards and systems, and are known to be safe.

While it is true that standard electrical designs are generally very safe during the operational phase of installations, the same cannot always be said about the construction, commissioning and decommissioning phases of an asset’s life.

Also, encouraging engineers to come up with innovative solutions often means modifying standardised designs. So the virtue of innovation carries the potential to create risks during the operational phase, if safety isn’t managed correctly.

A new set of skills

To effectively identify and manage safety risks during the construction, commissioning and decommissioning phases, the design engineer needs to have a new set of skills, not often included in the traditional education of a professional engineer. The engineer must understand not only how their design will function, but also understand the process of its manufacture, installation, commissioning, operation and decommissioning.

As part of Hydro Tasmania, Australia’s largest producer of renewable energy, Entura’s electrical engineers extend their skill sets and understanding of owning and operating assets by working through much of the same training as our asset managers and plant operators  (including isolation, locking, tagging, low-voltage rescue and general power plant safety procedures).

Our close and long-term relationship with the extensive power assets of Hydro Tasmania also allows our specialists to spend much more time in operational power stations and switchyards than many other consultants.

More than ‘ticking the box’

At Entura, we recognise that safety in design is not static, it can’t be done at just one point in time, it can’t just involve electrical designers, and it must be more than a ‘tick the box’ exercise if it is to make meaningful improvements to people’s safety as well as comply with regulations.

That’s why we integrate safety into the design process at all stages. Because design is not a simple or linear process, multiple safety review meetings allow the safety of the design to be formally reassessed at every step and for every phase of the asset’s life, in addition to the day-to-day awareness and integration of safety into all our design decisions.

Typically, at least two SID review meetings are held: one when the conceptual design is nearing completion, and one when the detailed design is 50–80% complete.  The SID meeting for a complex project could include representatives from the client, the construction team, the design team and the plant operator.

Any limitations in the designer’s knowledge of the construction, operational or decommissioning environments are compensated for by the broader knowledge available at the SID review meeting. Further stakeholders who may have additional safety insights for specific or unusual issues can also be identified.

SID review meetings give engineers in different disciplines or specialties the opportunity to communicate and explain their decisions. Where a decision made by one engineer could inadvertently create a safety impact on another discipline, this can be quickly identified and appropriately remedied.

When the concept of SID is valued by engineers and clients, and appropriately built into project processes (whether for dam safety, hydropower station safety, or electrical safety), it results in safer designs. And safer designs make safer assets and safer workers. Investing early in designing out any foreseeable safety risks will save money and time through the project lifecycle, and will protect your reputation, now and into the future.

To discuss how Entura can help you ensure the safety of your electrical assets, contact David Wilkey on +61 407 875 391 or Patrick Pease.

About the author

David Wilkey is a specialist electrical engineer at Entura. David has 20 years of experience in a wide range of electrical engineering projects including power system studies, power system and generator protection, generator connection rules, and primary plant electrical engineering. David’s primary interests include all aspects of electrical engineering for hydropower projects, such as hydro turbine governors, generator excitation and generator protection systems.

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Flood forecasting for a safer dam upgrade

An effective flood forecasting system is a vital tool for managing the significant risks that floods pose to communities, infrastructure and the environment.

If you can clearly understand the likelihood and scale of potential flooding and get accurate and timely warnings, you can better manage water infrastructure and implement safety plans in time to protect assets and communities at risk.

For hydropower businesses such as Hydro Tasmania, flood forecasting is a critical part of managing dam risk. Specialist power and water consulting firm Entura provides real-time inflow and flood forecasting and data management solutions to help manage Hydro Tasmania’s extensive catchments and 55 major dams.

Our most recent example of the risk-reducing benefits of flood forecasting systems is the major upgrade in 2014–15 of the Rowallan Dam on the Mersey River in Tasmania’s north, first built in 1968. The 43m-high earth and rockfill dam needed total refurbishment to be sure of a long, safe future.

Significant work was needed to bring the dam up to modern engineering standards and to increase its capacity to withstand large floods. To complete the necessary upgrade works, Rowallan Dam had to be excavated from crest to foundation on both sides of the spillway walls, exposing the heart of the dam.

The Rowallan Dam flood forecasting system allowed operators to confidently manage the flood risk during construction, ensuring the safety of construction workers and the public downstream, and protecting infrastructure and the environment from major flood damage.

The need for flood and lake-level forecasting at Rowallan Dam

During the construction phase of the major upgrade, Rowallan Dam faced a higher than normal risk of exposure to floods. Overtopping of the temporarily lowered dam crest during construction would compromise dam safety.

Kim Robinson, Senior Hydrologist and Project Manager for the Rowallan Dam flood forecasting system, said “This work was unprecedented in Australia because it was undertaken on a live dam, holding back Lake Rowallan – with a capacity of 130 000 megalitres.”

Kim explained that forecasts of lake levels were needed so that Lake Rowallan could be kept at the appropriate target level during the major excavation and refurbishment works. For safe work, the lake level needed to be lowered significantly by periodically opening a bypass valve to release water from the lake.

“The lake level needed to be low enough for safety, while also not losing too much valuable water, and potential revenue, by releasing too much water through bypass valves rather than through the power station,” Kim said.

As well as the required forecast of lake levels, a flood forecast was needed to indicate when emergency backfilling of the dam crest may be needed.

“The sensitivity of when to trigger this kind of action was a particular challenge” said Kim. “If backfilling was not carried out in time and a flood breached the construction works, the dam would be at risk of failure, with serious consequences for the storage downstream and potential impacts on communities.”

On the other hand, triggering an emergency backfill would be likely to delay construction by a year, with large financial impacts. “Backfilling is expensive and would risk extending the construction period into the wet season and the following summer,” said Kim, “which would be very costly both in terms of construction and from losing water that could have been used to generate power”.

A robust, effective flood forecasting solution

The solution to maintaining optimum lake levels and flood preparations during the Rowallan Dam upgrade was to develop a best-practice flood forecasting system, combining measured data from sensors at key locations with rainfall forecasts from weather forecasting agencies into a hydrologic model of the catchment.

“The modelling predicted lake levels and the time it would take for water to reach critical levels that could jeopardise the dam, always ensuring sufficient time for emergency backfilling,” Kim Robinson said. “The critical level varied depending on the depth of construction works, and maintained the same level of flood risk at all times.”

The entire modelling process ran automatically and provided an updated forecast every two hours during the construction period. Plots were developed showing the best-estimate forecast of inflow and lake level and rainfall over the catchment. The operators and construction managers used these plots to guide the operation of the valves to keep the lake at appropriate levels and to ensure appropriate preparation for emergencies.

Kim Robinson explained that alerts were set to trigger if the forecast exceeded the critical level. Plots were disseminated continually via email and a website. In an emergency, SMS and SCADA flood alerts would be sent out to relevant parties. If a flood alert was issued, the dam safety emergency plan would be activated.

“The system was made more robust by building in redundancies in the modelling and developing a stand-alone system at the dam site that did not require continuous connection to the database. This could be used if communications with the dam site were lost,” said Kim.

Striving for accuracy and certainty

For users to have confidence in the outputs of the flood forecasting system, it was important that the input data and hydrologic modelling were as accurate as possible, and that the level of certainty of the forecasts was clear.

“A plan was put in place to ensure that critical rainfall and flow gauges for the modelling were operational and that any maintenance required was undertaken within strict timeframes,” Kim Robinson said. “We developed routines to automatically check all input data for errors or missing data, and send alerts if inconsistencies were detected.”

Kim explained that the flood forecasting outputs included indications for operators of the uncertainty of both the rainfall forecasts and the modelling. “We developed the rainfall forecast uncertainty measures by comparing forecast rainfall to rain-gauge data over a historical period. The model uncertainty was estimated by running the model over a historical period with historical rainfall as input, and comparing outputs with measured lake levels,” he said.

The model has permanent ongoing value to the business and is being transitioned into the ongoing inflow and flood forecasting system which is used by Hydro Tasmania to manage power generation and dam safety risk. Learnings from this project are also being rolled out across the rest of a forecasting system which produces forecasts for 31 storages across  Hydro Tasmania’s portfolio.

To discuss how Entura can partner with you to develop a best-practice flood forecasting system to help you better manage your flood-related risks, contact David Fuller on +61 438 559 763, Phillip Ellerton on +61 439 010 172 or Shekhar Prince on +61 412 402 110.

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Smart communities: a win–win for all grid players?

As the electricity sector is revolutionised by new distributed generation and storage, can all the players survive? Is it possible for everyone to win?

The possibility of the death spiral of the grid and how it can survive the challenges of distributed generation and storage have previously been discussed by my Entura’s Donald Vaughan.

We believe that a grid, in a slightly different shape and form, is essential for the future of the electricity industry . And, if we get it right, this should be good news not only for electricity utilities, generators and retailers, but also for consumers and their communities.

The energy revolution

The electricity sector is on the threshold of a new era. In the same way that the introduction of digital cameras and mobile phones turned photography and telephony inside out and upside down, the electricity industry is being shaken up by a major new paradigm in which local generation, storage and bi-directional power flows in the network are blurring the boundaries between the key, discrete players in the traditional grid.

The traditional players – generators, transmission and distribution providers, retailers and consumers – are giving way to hybrid concepts such as ‘gentailers’ and ‘prosumers’. And new ‘smart’ technologies are giving consumers greater control over their timing and level of power demand.

At the same time, the grid is still required to be able to provide all the energy needed to support maximum demand, and that’s expensive. It’s like buying four cars for a family of four, just because once a year they might all be needed at the same time.

But, if consumers leave the grid, they will find it expensive to install enough solar panels and batteries to meet their own maximum demand and cover periods of cloudy, cold weather. They’ll be footing the bill for their own ‘four cars’, with no way to share the costs.

Moving towards a shared energy vision

A workable, clean and affordable solution that benefits consumers but also helps the grid escape the death spiral may be to produce renewable energy locally, but in a controlled fashion, complementing grid operation. Let’s call this a ‘smart community’.

The smart community might be a group of consumers within a geographical area such as a suburb, who, while still connected to the main grid, generate and store a proportion of their own power through distributed renewable generation, and use smart technologies to manage their devices and control their power usage to get the best value from their own power infrastructure.

This community can trade energy, not just between individuals, but also among other groups of consumers, or with the main grid itself. They will utilise the grid efficiently, through demand control and embedded generation control, and even support the grid in times of need, and charge for that service.

In this scenario, the grid provides any extra power these communities may need and gives them a sharing mechanism, but the opportunity to participate in the energy market gives the smart community more ‘bang for the grid-charges buck’. Neighbours and communities can share their own locally produced and stored energy and trade it in the energy market when the price is right – increasing the amount of clean and affordable renewable energy in the power mix, helping to democratise the energy system, and keeping some of the sector’s profits within the community.

But this win for the community does not have to come at the expense of the grid. Instead, the grid still benefits through less capital works required to manage total demand, because the smart community demand is capped by smart controls. And the smart community can also operate as a ‘virtual power plant’, providing generation or back-up to the grid at times when the community’s generation is greater than its demand.

For electricity retailers, distributors and other players in the electricity sector, providing this kind of ‘smart’ service to communities interested in taking more control of their energy generation, storage and use opens up a potential new revenue stream in the changing electricity market – and it is an opportunity still up for grabs.

Can ‘smart communities’ really work?

What makes smart communities possible is a ‘smart community controller’ for rapid demand-side response and sub-second control of loads.

As part of Hydro Tasmania, Australia’s largest renewable energy generator, specialist power and water consulting firm Entura contributed to the design and development of the controller that has been used successfully in the King Island community since 2013. The super-fast demand control system helps to keep the King Island power system at high levels of renewable penetration, by subtly managing customers’ power loads.

For example, during sudden, short drops of wind power, hot water boilers across the island are turned off for less than a minute. This reduces the total load and prevents the need for a conventional generator to start up, maintaining high renewable penetration – and customers don’t even notice the difference.

And, in the reverse scenario, if there is a surplus of renewable energy, it may be possible in future to offer it to customers at lower rates rather than spilling it. This is especially valid if storage is available.

This advanced control technology is also helping other remote communities (such as the Pacific island of Yap) balance their power demands to maximise their use of locally generated renewable energy when these sources are available.

So, enabled by very clever technology, this model of a smart community really does work. And, if developed further, promises to be a win–win for all participants in the grid.

To discuss how Entura can work with you to implement the smart grid technologies that underpin successful off-grid, hybrid, remote area, or smart community developments, contact Silke Schwartz on +61 407 886 872.

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Buying time: managing risks with flood forecasting

Almost every day, somewhere in the world, floods are putting lives at risk and causing major damage and financial impacts to buildings, critical infrastructure, agricultural land and crops, and the environment.

In 2013, almost 10 000 people were killed worldwide by flooding, and the lives of more than 32 million people were adversely affected by flood disasters. In Australia alone, the estimated cost of flooding is $400 million per year, and around the world the costs rise into the billions.

If you understand the specific risks and consequences of flooding in your location and area of operation, you can implement suitable emergency action plans to best manage these potentially catastrophic events, saving lives, reducing costs, and minimising impacts on property, infrastructure, communities and the environment.

Flood forecasting is a vital component of a total flood warning system. With increasing severity and frequency of extreme weather events likely in the future, effective flood forecasting systems are urgently needed to provide the accurate and timely warning of impending flood events that will improve public safety and minimise flood-related damage and costs.

Flood forecasting systems allow you to manage risk

Flood forecasting systems can be used by local authorities, water managers and owners of water assets to better manage a range of risks. By providing warning time of an impending flood, forecasting systems offer a window of opportunity for good decision making to reduce public safety risk through warning or evacuation, and to ensure informed management of water infrastructure.

Whenever a large volume of water is held or is transferred under pressure, potential risks to public safety and downstream infrastructure arise.  The normal operations of water assets such as dams, pipelines and hydropower facilities regularly involve potential risks to the safety of both the general public and staff involved in construction, operation and maintenance. In this context, successful flood forecasting has obvious application, such as allowing operation of a dam to minimise flood peaks downstream, informing the timing or method of dam construction to avoid inundation of the works, or helping determine the need for emergency evacuation.

Sometimes flood risks can also be opportunities, if managed carefully. Flooding offers the gift of abundant flows to owners of hydropower assets or water supply or irrigation storage facilities. In this context, flood forecasting can provide strategic operational benefits to water managers by providing enough warning of impending large flows to allow optimal preparation for capturing, storing and using the plentiful water.

How are floods predicted?

Flood forecasting systems combine measured rainfall data and rainfall forecasts from weather forecasting agencies into a hydrologic model of a catchment. This model converts the rainfall into runoff and flow in rivers, or inflows to storages. These flow forecasts can be corrected with measured flow data in real time where this is available.

For some applications, these flows provide inputs to a hydrodynamic model of the river and surrounding area to give forecast flood levels and inundation areas.

The forecasts can then be displayed graphically or in another appropriate format for operators and water managers to use to manage flood risk.

The accuracy of flood forecasting depends on both the accuracy of the input data (rainfall, forecast rainfalls and flows) and the accuracy of the hydrologic modelling.

There is a necessary trade-off between forecast times and accuracy. The most accurate forecasts are based on measured flow data, but this gives very little warning time as the flows are already in the river. Forecasts based on conversion of measured rainfall to runoff using models give longer warning times but greater uncertainty.  The longest warning times are achieved using forecast rainfall data, but these forecasts are the least certain.

Despite greater uncertainty, longer term forecasts can indicate that a water manager should keep watch for the possibility of a flood, and can offer more time to ensure that the correct procedures are in place to manage a potential flood risk, and to take actions such as optimum storage management to capture floods.

Best practice for successful flood forecasting systems

Successful real-time flood forecasting relies on capturing and storing accurate input data, reliable modelling, easily interpreted results, and timely alerts and warnings. Best-practice flood forecasting systems should include:

 Applications of flood forecasting systems

Flood forecasting is a critical part of managing dam risk and public safety risks across a dam portfolio. As part of Hydro Tasmania, Australia’s largest water manager and renewable energy producer, specialist power and water consulting firm Entura provides real-time inflow and flood forecasting and data management solutions to help manage Hydro Tasmania’s own extensive catchments and a complex system including 55 major dams.

We’ve built on our experience in dam safety to offer flood forecasting expertise to a range of clients throughout the Asia-Pacific region for other important applications, such as providing the advanced flood warnings needed to protect assets and communities at risk, whether in regional areas or large metropolises.

To find out more about how Entura can partner with you to develop a tailored and complete solution to help you better manage your flood-related risks, contact David Fuller on +61 438 559 763 , Phillip Ellerton on +61 439 010 172 or Shekhar Prince on +61 412 402 110.

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What is the best dam type for my dam site?

Asking ‘what is the best dam type for my dam site?’ is a key question in the early stages of planning a dam project.

A number of dam types are being used around the world, such as concrete-faced rockfill dams (CFRD), roller-compacted concrete (RCC) dams, and asphalt-core rockfill dams, amongst others. Consultants that specialise in a particular dam type may offer a biased answer to the question, which is not in the best interests of the project.

The most appropriate response is that the best dam will depend on the unique characteristics of the dam site – available materials, climate, geology, topography, river flows, seismic risk – just to name a few.  This may sound obvious, yet it is surprisingly often ignored.

Although it is important that we take our experience and learnings from other projects and apply them to any new dam project, it is equally important that we do not force a past solution to fit a new dam site without considering that particular site’s uniqueness.

So, for any dam site, it is important to undertake an unbiased dam-type assessment that takes into account the range of site-specific conditions balanced against the broader project constraints (such as cost optimisation, and the availability of local design and construction expertise).

The following examples of dams with which I’ve been involved show how particular characteristics of each dam site determine the appropriate dam type.

Responding to local climate, geology and materials in Tasmania

On the west coast of Tasmania, Australia, where the rainfall is around four metres per year, Hydro Tasmania, Australia’s largest renewable energy producer and water manager, has constructed nine CFRDs.  Good rockfill was available at all of these sites.  Key reasons why CFRDs were used at these sites, rather than central-core earth and rockfill dams, included both the lack of quality clay material and the high rainfall in this region. High rainfall would significantly disrupt and delay the construction of clay-core dams due to issues with the compaction of the clay material, whereas construction of CFRDs could continue during rain. Asphalt-core dams might also have been possible in these local climate conditions, but would have presented different challenges for river diversion.

One of these CFRDs, the 82m-high Crotty Dam, faced potential instability should a traditional side-channel spillway be cut into the abutment slope, due to the steep abutment slopes and identified geological defects.  As a result, for the first time in the world, a spillway was created over the top of a high CFRD wall, combined with a large-capacity bottom outlet gate installed in the diversion tunnel.  This solution included an articulated concrete slab that would allow the spillway to move without cracking as the rockfill settled over time.

The solution at Crotty Dam was unique, but it was heavily influenced by the characteristics of the dam site and the construction materials available, which allowed a very stiff rockfill to be constructed, minimising the amount of settlement. The solution has proven a good choice, operating well for more than 20 years.

However, the particular solution that was successful for Crotty Dam may not be appropriate for other dam sites, where the dam might be significantly higher, where rockfill may be of poorer quality, or at a site with greater flood discharge or higher seismic risk.

A process of elimination in Papua New Guinea

In 2012, Entura undertook a detailed dam-type assessment for a site in Papua New Guinea, and in this case, the ultimate decision about the best dam type emerged from considering many site characteristics and then eliminating inappropriate dam types to reach a subset of viable possibilities.

The site was in an extremely high rainfall area (with approximately ten meters of rain each year), the rock foundation had relatively low strength and low stiffness, river flows were consistently high, there was deep alluvial material that would need to be removed or sealed, and the site was in a region with relatively high seismic risk.  Sources for concrete aggregate and rockfill were available.  However, due to the lack of strength and stiffness of the foundation rock, a conventional concrete gravity dam was not possible; and the extremely high rainfall posed significant challenges for a central clay core and rockfill dam.

As a result, the choices narrowed to a CFRD, an asphalt-core rockfill dam or a thick, trapezoidal RCC (or hard-fill) dam.  Ultimately, an asphalt-core rockfill dam was chosen as the preferred solution, as the core could be placed during high rainfall, the load would be adequately spread over the foundation, and it was considered a resilient design for the seismic loading.

Another important factor influencing the choice was that an asphalt-core rockfill dam would minimise problems and delays should the upstream temporary cofferdam overtop, because asphalt-core rockfill dams are always complete up to the current height of construction with no further work required below this level. Some other dam types require further work on the dam’s upstream face after the dam wall is constructed to its full height, requiring flood water to be pumped away to enable final-stage activities to proceed.

Challenges influencing RCC dam design and construction  

Many design and construction decisions for RCC dams can be significantly influenced by specific site conditions – for example, should the proportion of cementitious material (cement and fly-ash) in the RCC mix be low or high? Should one use conventional facing concrete, grout-enriched RCC or a PVC upstream membrane? Is RCC best delivered by truck or conveyor?

A significant influence on the design of the Wyaralong Dam in Queensland was the benefit of using an onsite, but inferior, sandstone aggregate for the RCC aggregate.  Using the onsite aggregate would reduce costs and benefit the local community through avoiding major aggregate haulage on public roads.

Using the onsite aggregate also influenced the investigations that occurred as part of the normal trial program used to develop an appropriate RCC mix. This in turn influenced the design of the dam because the trial mix program identified an issue with the surface durability of the RCC. Grout enrichment of the facing RCC was not suitable, so a conventional concrete using a high-quality basalt aggregate was used to provide the necessary durability.

The topography of the left abutment provided a natural ramp for an articulated truck delivery system.  This delivery system proved to be very flexible, but it was important to develop a suitable RCC mix for truck delivery.

One size doesn’t fit all

There is no easy or immediate answer to the question posed at the start of this article.  No single dam type offers the best solution for every dam site.  Although lessons learnt from other dam sites can help to rapidly narrow down a set of preferred dam types to consider in more detail, the appropriate dam type must be influenced by the unique conditions of the dam site.

Specialist power and water consulting firm Entura has significant experience with a wide range of dam types across the Asia-Pacific and southern African regions, particularly CFRDs and RCC dams.

You can read more about the way in which we responded to specific site characteristics for three RCC dams and the reasoning underpinning our design decisions in my 2012 ICOLD Conference paper “Unique challenges influencing the design and construction of three recent Australian RCC dams”.

If you would like to discuss how we can assist you with selecting the most appropriate dam type for your dam site, please contact Richard Herweynen on +61 3 6245 4130 or Shekhar Prince on +61 412 402 110.

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.

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How can the grid survive distributed generation and storage?

A lot of the talk about the ‘death spiral’ in the demand for electricity from the grid in Australia has centred on the distribution end of the equation and the downside or asset risk associated with ‘disruptive’ technologies such as solar PV and storage.

I’ve suggested before that talk of the death of the grid may be premature. But how can the electricity industry respond to the advent of distributed generation and storage to embrace its potential benefits?

The grid is still required in some form

Historically, we have moved from a decentralised or local model of electricity generation and consumption to a more centralised generation model through the development of large-scale synchronous machines (hydro and thermal).  This was driven by efficiencies and the high energy demands, both in volume and reliability, of industry.

The reduction in cost of distributed generation and storage is changing the efficiency equation for smaller users.  But distributed generation and storage is not a viable alternative for all energy users, so the grid must remain in some form.

Balancing the value and cost of grid connection

All connected parties benefit to some extent from being connected to the grid.  Generators get a delivery mechanism for their product.  Industry gets an important input to production with high levels of reliability.  Small businesses and homes get access to controllable and comparatively inexpensive energy.  Customers with distributed generation and storage get access to a sink or source that can increase the value of their investment and cap their exposure to resource or equipment failure.

The network adds value to each of these transactions since without it the individual parties must all become self-sufficient. But this added value is not always perceived as adequate compensation for the cost of grid access.  This distortion will ultimately lead to an over-investment in distributed generation and storage to go with an existing over-investment in the grid.

Reaping the benefits of distributed generation and storage

I think two changes could foster more efficient co-development of network infrastructure and distributed generation and storage:

1. developing a real-time communication and control protocol with customer loads and storage
2. re-evaluating the worth of the network, basing value not on sunk cost but on utility.

Developing a real-time communication and control protocol

To enhance the synergies between distributed generation and storage and the wider network, real-time status and control of loads and storage must be available to whoever needs it.  The mechanics of this are not difficult unless response must be rapid.  The sooner a standard or an accepted architecture can be adopted, the more efficient the transition and the faster the realisation of benefits.

One of the great challenges of distributed generation and storage for network operators is that it fundamentally changes the assumptions that can be made about the predictability of system demand in the minute-by-minute operation of the grid.

Linking available generation more directly to that demand alleviates some of the risk associated with the increased volatility on the demand side.  It turns a looming risk into a relatively benign outcome, perhaps even a beneficial one.

For instance, if the decision to store is based on price and there is a small variation in this price setpoint across the storage fleet, then the amount of variation within one dispatch interval could be quite high, requiring larger amounts of regulation reserve to be dispatched for a larger percentage of dispatch intervals.

For large-scale renewable generators, linking to loads and storage may provide a way to increase demand to better utilise high potential yields that would otherwise be constrained in the market. The simplest example of this is a wind farm in a region where the interconnector to a larger region is at its limit.  The wind farm output will be constrained even if more wind is available, unless additional demand can be found on the same side of the constraint as the wind farm.

Re-evaluating the worth of the network

Distributed generation and storage decreases some customers’ reliance on the grid. Those customers may value the grid less, but still pay the same amount to access it. And those customers are now saying this doesn’t make sense.

We know the grid does offer value. In capability terms (reliability and security), the grid is very valuable to most customers, even if they don’t appreciate it. But the grid is over-built in capacity terms for a market awash in distributed generation and storage. For many consumers, it is no longer a choice of whether to invest in distributed generation and storage, but rather a choice of what rating of inverter or storage.

Network charges cannot continue to be based purely on the sunk cost of the development and provision of the network. This worked when there was little alternative.  But now that distributed generation and storage is viable for many, it is up to the network to improve its perceived value to keep its customers.

If customers’ willingness to pay is capped by a credible alternative, there is an easy choice for the rational customer with distributed generation and storage, and there is a hard choice for the electricity industry – change your pricing and enhance your product, or lose your customers.  This reality is better dealt with sooner than later.

The grid of the future must be developed by considering distributed generation and storage, and comparing the relative costs of network development against distributed generation and storage developments.

It is critical that we ensure the grid is right-sized for the future.  This will lead to any number of on-grid, hybrid or fully off-grid arrangements.  For an efficient outcome, the flexibility and agility of grid design and operation must complement rather than duplicate the capability provided by distributed generation and storage.

It’s not the fall that kills you …

The grid has a role to play in the future delivery and consumption of electricity.  But unless clear and correct signals are given to customers, the network will not follow an efficient trajectory to a new and suitable steady state, a soft landing.

A number of changes will help us create a bridge between where we are now (a grid that is increasingly unappealing to customers with distributed generation and storage) and where we need to be (a market with a seamless grid efficiently linking generators and loads).  These changes centre on standardising technology and being open to adaptive network pricing and planning.

Accommodating the growing competitiveness of distribution and storage is essential to the long-term wellbeing not only of the electricity industry but also the economies it has nurtured and that sustain us all.

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

About the author

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

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Breathing new life into ageing assets: asset management in practice in PNG

The remote Ok Menga hydropower station in the Western Province of Papua New Guinea is vital to the operation of the Ok Tedi mine (OTML). It offers an example of just how expensive it can be when ageing power stations deteriorate and become increasingly unreliable.

The Ok Menga hydropower station provides almost three-quarters of the power needed to operate the mine, with the remaining power generated using expensive diesel fuel. The local power network is isolated and not connected to any of the country’s electricity grids, so any failure of the Ok Menga power station is costly.

If one of Ok Menga’s two generating sets is out of action, replacing that amount of hydropower (about 30 MW) with diesel-generated power could cost around AUD$650 000 a day in fuel alone. Worse still, a full outage of the power station could cause the mine to shut down, losing copper, silver and gold production worth around AUD$4 million per day!

The Ok Tedi mine had been scheduled to close in 2015, so preventative maintenance had not been a high priority for its owners, and the Ok Menga power station had become run down. When the mine’s proposed closure was delayed to 2025, a new operational strategy was needed to wring at least another ten years of useful and reliable life out of the more-than-30-year-old Ok Menga power station.

OTML needed the help of skilled asset management experts to extend the life of the Ok Menga power station, so it engaged specialist power and water consulting firm Entura to conduct an extensive condition assessment and come up with a risk mitigation plan to get the best out of the station in a cost-effective way. This also included building the skills and knowledge of OTML staff who had not had any formal training for years.

Ok Menga’s unique challenges

Although Ok Menga had many of the same asset management issues as any other hydro plant, it also presented some unique challenges in terms of risks and maintenance strategies. Its isolation and association with a large mining operation challenged many of the conventional rules fundamental to asset management in larger power utilities.

Leigh Smith, specialist consultant in asset management at Entura, explained: “In our asset management approach, we needed to take into account how the particular characteristics and circumstances at Ok Menga created differences for aspects such as the design life, planning outages, access to the plant, the holdings of critical spare parts, and the consequences of faults. For example, because outages at Ok Menga incur such high costs, we needed to replace rather than refurbish machinery, because they couldn’t have the machines offline for long.”

Bringing risks under control

Entura applied its best-practice asset management approach at Ok Menga by thoroughly assessing the condition, performance and remaining useful life of all aspects of the station, and developing a risk mitigation plan including urgent actions to remedy serious risks, and ‘quick wins’ to improve the state of the station quickly, cheaply and effectively.

As Leigh explained, “We report the condition of the plant in terms of business risk, and the mitigation strategies we propose are all about reducing risk to a level that’s acceptable to the business in cost-effective and practical ways”.

Quick wins and priority actions

At Ok Menga, two ‘quick win’ projects were identified to mitigate critical risks. The main inlet valves were difficult to access and in poor condition with no critical spare parts on site, and the original analogue turbine governors installed in the 1980s needed replacing but no governor spare parts were available.

“A failure in either or both of these areas was seen as likely in the foreseeable future and would create serious consequences of a prolonged forced outage for one unit or even the complete station,” said Leigh.

Replacements for the main inlet valves would take more than 18 months to deliver, so an emergency repair kit containing critical spares was ordered immediately. Replacement of the governor controllers with newer digital technology was also rapidly initiated to quickly reverse declining reliability.

Leigh said, “Getting these ‘quick win’ projects going straightaway was imperative and immediately reduced very significant risks.”

As well, at Ok Menga, three priority asset risk mitigations were identified relating to the station’s rock trap, unit 1 turbine and the dewatering and drainage system. The rock trap was found to be full, and cleaning it out was initiated quickly. Ok Menga’s unit 1 turbine was worn so the unit 1 runner and cassette were replaced. The security of the dewatering and drainage system had been degraded and it was at risk of failure so Entura recommended that it be upgraded to a system with greater reliability and redundancy.

“Because these priority actions minimised damage to turbines, avoided possible turbine malfunction, and reduced the risk of the powerhouse being flooded, they made a big contribution to reducing the owner’s overall risk exposure,” said Leigh.

Building capacity

To fill skill gaps at the Ok Menga power station, Entura developed an Australian-accredited program to train new and existing hydro operators. Local staff were included in the asset management process and have now had first-hand exposure to best-practice techniques.

“The owner of this power station is very committed to a sustainable future, and this extends to its staff.  The platform is now set for local staff to build on their newfound knowledge and continue to improve their understanding and skills in asset management,” explained Leigh.

Entura has developed its knowledge of asset management through our involvement over the past 100 years with the extensive power and water assets of Hydro Tasmania, Australia’s largest renewable energy producer. Our approach to asset management is recognised as best practice.

“We have spent considerable time learning and developing our systems and knowledge, and this enables us to deliver cutting-edge asset management techniques to our clients without the expense they’d incur if they started from first principles,” said Leigh.

Entura’s holistic best-practice asset management approach at the Ok Menga power station delivered a range of benefits including reducing immediate and longer term risks, and increasing the knowledge and skills of local staff – saving OTML the time and cost of developing its own in-house programs.

If you would like to discuss how Entura can assist you with assessing your hydropower plants or other power or water assets to minimise risk and maximise efficiency and useful life, please contact Leigh Smith on +61 419 884 318 or Shekhar Prince on +61 412 402 110.

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‘Sundown, sunrise’ or ‘reform or die’?

The Grattan Institute’s recently released report ‘Sundown, sunrise’ observes that household solar PV will soon be cost-competitive under existing tariff structures, while at the same time bemoaning the subsidies it has attracted, and the uneven burden of these subsidies on all network users.

But it’s important to read beyond the executive summary.

Knee-jerk reactions

The report has been criticised for headlining the imbalance between the costs and benefits of household solar. Critics argue that the Grattan Institute’s model is too narrow, and doesn’t account for the other benefits of the high levels of subsidies to date.

But focusing our attention solely on the details of this aspect of the report may be crowding out some of its more important findings.

A fair share

That we now have a credible and viable solar PV industry in Australia shows the success of the subsidy arrangements that currently exist.  The retirement of these subsidies means that they will play less of a role in the future but the impact of PV will only grow.  Dwelling on this specific issue is a distraction and almost irrelevant for future policy concerns.

Ultimately, we want everyone to pay their fair share.

Former high feed-in tariffs or high subsidies for solar PV installation led to solar customers gaining either a disproportionate or overstated amount of the value created by their solar installation.  At the same time, the rise of solar PV has exacerbated the effect of declining energy use on the economics of the grid.

In the long run, we must try to address both of these issues (and a few more besides!) if we are to make the best use of these emerging technologies without wastefully underutilising existing network infrastructure and generation capability.

Looking into the future

If we accept that past arrangements had unintended consequences, we can turn our attention to the insights the report contains about the possibilities for achieving better future outcomes. I personally don’t believe the electricity industry is incapable of adapting (more on this here).

The report’s insights about the future of the network, the solar industry and energy storage lead to the following conclusions:

• Existing tariffs do not properly account for the network costs and network benefits of distributed solar PV and so some tariff reform is needed to address this.
• Existing regulations may not create optimal outcomes for networks or network customers.
• Network planning processes don’t always fully consider distributed generation or non-network solutions as potentially beneficial alternatives to replacing assets or augmenting the network.

The report offers some early suggestions about how tariffs, planning rules, asset valuation and regulation should be adjusted to address the looming challenges, avoid further entrenchment of disparity between costs and benefits and possibly harness some untapped benefits from solar and storage.

This is the time to focus our thinking on how we can correctly incentivise distributed generation, large-scale generation, loads and network developments… because we know that today’s arrangements won’t be right for tomorrow.

About the author

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

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Eight principles for successful investment in renewable energy projects

When you are considering investing in a renewable energy project, a thorough due diligence investigation can identify the costs, benefits and risks, and lead to well-informed decisions.

In practical terms, this is about asking the right questions about the project, distinguishing when an issue is important and when it is not, and prioritising your efforts.

Why prioritise your efforts?  Because the unfortunate reality is that most due diligence investigations don’t result in an investment. As consultants, we are aware of this reality, but as part of a larger business that acquires, develops and owns renewable energy assets, we understand that effort and expenditure must produce results.

When we lead renewable energy due diligence investigations, we often start with a quick assessment to establish as soon as possible if there are any ‘show stoppers’. No matter how preliminary or comprehensive the assessment, these eight principles guide our considerations:

1 – Identify the motivation to invest

A thorough due diligence investigation will identify high-level issues such as sovereign risk, right down to detailed technical issues associated with the particular investment opportunity.

Your motivations as the investor will influence the assessment of these risks. It may not simply be all about financial return, but also a desire to limit carbon exposure or to increase corporate social responsibility. And if we understand your business, we can bring a clearer perspective to the assessment.

Traditionally, investors have relied on consultants to assess the technical issues in detail, but have preferred to assess high-level risks ‘in-house’. This approach is understandable, but it may not be making the most of your consultant’s knowledge. Most renewable energy consultants these days have been in the game a long time, and you will find them keen to provide a more holistic assessment of risk.

2 – Understand the business case

As with any investment decision, investors interested in renewable energy projects need to understand the level of investment of financial and human resources required for the project, and the likely returns for that investment – the business case.

Each project will have its own set of issues and risks to identify and potentially mitigate as part of a robust business case. Risks will affect the revenue stream, the cost of the project, and/or the social acceptability of the project.

An experienced due diligence provider can provide value by recognising the difference between issues that will materially affect the project business case and those that will not, or by identifying opportunities where others might only see risks.

3 – Understand the relevant markets, policies and regulatory frameworks

Renewable energy projects are often supported by government policies that recognise the environmental benefits of clean generation and support the revenue stream for the project. It is essential to understand both the commercial market for your energy and this policy environment.

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

4 – Understand the impacts of the variability of renewables

Renewable resources such as solar, wind or small run-of-river hydropower schemes generate power with a variable output that can be forecast, but is not necessarily available on demand. This feature of renewable energy can lead to quarterly or annual variations in generation and in revenue that are beyond the control of the owner.

However, renewable projects do not have variable fuel costs. So by weathering the short-term fluctuations of renewable generation through prudent technical and financial risk management, you can achieve greater long-term certainty in your business case than with non-renewable generation projects.

The variability also means that when the resource is available (for example, the sun is shining), you want your project to export energy to the electricity grid without constraint. Therefore, for renewable energy projects, the grid connection arrangements can mean the success or failure of your project.

5 – Minimise uncertainty of revenue

The variable nature of renewable generation can create short-term uncertainty in revenue; however, long-term certainty in revenue is generally a must-have for a renewable energy project looking to sell its power output.

In some markets, set tariffs may be offered from government bodies for renewable projects. In markets with a floating electricity price, long-term power purchase agreements are often sought with counterparties such as retailers or large-scale energy consumers.

There may not be much assistance a consultant can provide on this issue – except to remind you to read the fine print of any agreements and, if the project does not have a confirmed buyer for the power, make sure you know the risks!

In terms of what the project is technically capable of generating, an operational project has more certainty than a development site, and may be more attractive for some investors.

6 – Manage capital and operational expenditure

Renewable energy projects require a large upfront capital expenditure. Depending on your risk appetite as an investor, exposure to risk can be managed through the contractual arrangements with the developer, equipment suppliers and the construction contractor. Comprehensive long-term operations and maintenance agreements are often available, which reduce your risk, but at a cost.

One issue worthy of particular note is construction delays. Investments that are otherwise sound can suffer due to delays in construction, which can have significant impacts on the expenditure and revenue profiles, and the terms of any debt provision.

7 – Develop and maintain community relationships and acceptance

Renewable energy projects operate within communities. There will be a range of attitudes towards your project and relationships to manage, and it will be up to you to develop and maintain a healthy relationship with the community.

Your community may see your project as a major contributor to the local economy through direct employment and indirectly through contracting. The community may even expect you to play a leading role in supporting local community activities through sponsorship and other activities.

8 – Ensure right action and compliance

An opportunity to invest in a renewable energy project might occur at any stage of the project. Regardless, the nature of the due diligence is usually very similar – have the right actions have been undertaken, does the project comply with its commitments, and will it continue to comply into the future?

Because Entura is part of Hydro Tasmania, Australia’s largest renewable energy producer, we understand what it means to live with the full consequences of investment decisions and risks. So we approach due diligence for our clients in the same way we would if the investment opportunity was our own.

That means developing a full understanding of the proposed project, discovering any risks that could prevent its success, and finding the best ways to make the most of the project’s strengths and avoid any possible weaknesses.

If you are seeking to invest in renewable energy, Entura can assist you with practical, expert due diligence services for proposed or operational projects in the Asia-Pacific region. Please contact Patrick Pease or Silke Schwartz on +61 407 886 872.

About the author

Seth Langford is a specialist renewable energy engineer at Entura and has been working in the wind industry for more than ten years. Seth has been involved with major wind farm projects as a technical specialist and a team leader for feasibility studies and due diligence projects in India, China, Australia, Sri Lanka, South Africa and New Zealand. Seth has spent considerable time assessing greenfield and operational wind farms on behalf of developers wishing to acquire wind farm projects.

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Climate resilience in practice

Climate change poses new uncertainties and risks to power and water asset developers, operators and financiers, in addition to the challenges already facing these sectors.

Higher temperatures, changes in water availability and rainfall, more frequent and severe weather events, and natural disasters may pose threats to power and water infrastructure as well as communities and the environment.

These risks are being increasingly recognised and acknowledged globally. But what practical steps can we take now to prepare our power and water assets and businesses for the impacts of climate change? Can we do more than ‘mitigate’ or ‘adapt’? Could innovative and timely action to manage risks strengthen businesses and increase their resilience to a changing climate?

The idea of building climate resilience recognises that climate change exists and will result in various forms of ‘shock’ to the systems in which we operate. Climate resilience is about taking action now to ensure that our business and economic systems and operations are well prepared for the types of disturbances that we may see more of in the future.

Climate resilience built into management strategies

Despite most businesses now recognising the realities of a changing climate, few have started to build climate resilience into their projects or operations. In a 2011 survey, 90 per cent of companies had faced climate-related impacts within the previous three years, but only 30 per cent were actively responding to those threats.

Although the possible future impacts of climate change are uncertain, including the financial implications for businesses, now is the time to invest in building resilience. Building climate resilience must become a standard component of overall risk management strategies, particularly for water and energy asset owners and operators.

The more we understand the potential impacts of climate change and risks to our projects and our operations, the better we can prepare, adapt, and build resilience to climate change impacts.

An owner–operator perspective

Hydro Tasmania, Australia’s largest renewable energy producer and water manager, has already experienced a level of climate variability, and is well aware of the implications of increasing variability in the future. This includes changes to average long-term system inflows, higher risk of major droughts, and occurrences of unseasonal and unprecedented weather conditions. Hydro Tasmania has been undertaking a range of activities that build its climate resilience.

As part of the Hydro Tasmania group, specialist power and water consultant firm Entura supports the business through a number of actions that safeguard Tasmania’s ongoing access to high-quality, reliable water and power.

Understanding vulnerability through climate change analysis

For Hydro Tasmania to address its vulnerabilities to future climate change, it first needed a more comprehensive understanding of how Tasmania’s climate and catchments may be affected in the future.

Entura collaborated with the CSIRO (Australia’s national scientific research organisation) to undertake the first fine-scale climate and river system modelling for Tasmania, through the Climate Futures for Tasmania and the Tasmania Sustainable Yields projects.

The results indicated that under climate change Tasmania could expect gradual temperature rises, increased rainfall over coastal regions, reduced rainfall over central Tasmania, changes to run-off patterns, and changes to the frequency and severity of extreme weather events including increased rainfall intensity and floods.

These conditions could have secondary impacts such as asset and building damage, sediment and debris accumulation, increased bushfire susceptibility, and environmental and social impacts.

Generation planning and drought management

With this improved understanding of future climate impacts, Entura is helping Hydro Tasmania identify and prioritise a range of actions. State-of-the-art hydrographic data and hydrological forecasting enables Hydro Tasmania to improve generation planning, management of storages, and drought management.

Generation can be planned over a range of time-scales and demand scenarios, supported by long-term storage targets and storage operating rules. Additional storage can be accessed to help drought-proof the system in low inflow periods. When lake levels are low, management procedures built into the storage operating rules minimise risks and impacts on social and environmental values.

Flood forecasting, dam safety and emergency planning

Being climate resilient also means preparing for ‘too much’ water. While higher rainfall can result in increased flooding, it can also be a gift to hydropower asset owners, if managed carefully.

Entura has helped Hydro Tasmania assess how to upgrade its power schemes to maximise the benefits of predicted water increases for increased power generation. We have developed flood forecasting and flood support systems, and supported Hydro Tasmania to make improvements to its dam safety and emergency planning programs.

And by being involved in upgrading dams and designing spillways to withstand predicted increases in the frequency and magnitude of floods, we’re contributing to building greater potential resilience into Hydro Tasmania’s assets and operations.

Managing assets for long-term sustainability

Climate resilience for long-term sustainability is a key consideration for a proactive, risk-based asset management program. Entura builds climate risk management and resilience into our projects right from the earliest stages of planning and throughout the design process.

We do this by fully considering and testing the range of operating scenarios and conditions that may be encountered, and building in robustness and flexibility to deal with the potential range of situations.

For example, we:

• explore ways to reduce the damage to turbines due to increased silt, sediment and debris caused by extreme rainfall
• consider solutions to the potential thermal gain in power stations in warmer conditions and its subsequent impacts on generator temperature and performance
• evaluate how transmission line design might address the predicted climate variability along the length of transmission line corridors, and whether the present standards are sufficient for potential future conditions, and
• consider the impacts of wind loading, changes in drainage and the efficiency of foundations.

Protecting environmental and social values

Entura is providing ongoing support to Hydro Tasmania to build climate resilience into its operations while also managing environmental and social values.

This includes accommodating multiple users of water resources through maintaining adequate downstream flows for the environment, water supply, irrigation and recreational uses, and protecting fisheries resources and threatened species.

Supporting global efforts to build climate resilience

Entura supports clients throughout Asia, the Pacific, and southern Africa to build their own climate resilience strategies and actions. We help our clients understand the risks and potential impacts of climate change for their current and planned systems and operations – whether for hydropower, transmission, dams, irrigation or water supply – and advise them on the likelihood and consequences of these risks and impacts occurring.

Through understanding the vulnerabilities of our clients’ businesses, we help develop operational solutions that will increase resilience to future changes in climate and improve long-term business viability.

If you would like to learn more about building greater climate resilience into your power or water project or operations, whether for hydropower, transmission systems, dams, irrigation or water supply, please contact Dr Eleni Taylor-Wood on +61 3 6245 4582 or Shekhar Prince on +61 412 402 110.

About the authors

Tammy Chu is the managing director of Entura, one of the world’s most experienced specialist power and water consulting firms. She has extensive managerial and business development experience in the consulting engineering industry within Australia and internationally, focusing on business strategy, change and transformation, international sales, culture, and profit and revenue growth. As a civil engineer, Tammy specialised in the design and construction of mini-hydro and hydropower systems, project management, hydropower investigations, prefeasibility and feasibility studies, environmental assessments and approvals, resource investigations and resource water management. An active member of the engineering community, Tammy publishes papers on a range of subjects, and regularly presents at conferences.

Dr Eleni Taylor-Wood is Entura’s Principal Consultant, Environmental and Social Science. Eleni has 20 years’ experience successfully managing large-scale, complex projects that run over several years, as well as providing expert advice and independent review for a range of infrastructure and planning projects. She has worked on projects around the world including in Australia, Mozambique, South Africa, Iceland, Colombia, India, Malaysia, Mekong, Solomon Islands, Fiji and Papua New Guinea. Her experience covers a vast gamut of studies including: environmental and social impact assessment and management; strategic management of wetlands and waterway; feasibility and approvals for new hydropower projects, environmental flow determination and assessment, and sustainability assessments. Eleni is currently one of eleven Accredited Assessors under the Hydropower Sustainability Assessment Protocol worldwide.

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Less risk, more benefit: managing assets for long-term gains

Hydropower stations, like all technology or infrastructure, won’t stay efficient, reliable or safe without regular and ongoing attention.

Outages and failures caused by ageing or deteriorating infrastructure can be extremely expensive and serious, and far outweigh the costs of a well-targeted asset management plan. The costs of unreliability are even more significant for hydropower stations in isolated locations or where the power is relied on to run industrial or commercial operations.

But asset management isn’t only about avoiding disasters … It’s also about getting the most out of asset life or ‘getting more bang for your buck’. Owners and operators stand to reap rewards from improved performance and greater reliability if they protect and extend the lives of their investments using best-practice asset management techniques.

From basic to best practice

In today’s industry, significant amounts of time, energy and effort are invested in achieving desired plant performance at the lowest possible cost without exposing the business to unacceptable risk. Truly sustainable and successful businesses have found ways to balance these priorities, and have strategies in place to adjust the balance as needed when facing changing conditions.

Besides the large financial consequences of outages, failures of systems and equipment can also place the lives of workers at risk. Repairing and upgrading equipment and systems only after they fail is an extremely costly and dangerous way to manage assets. This kind of basic ‘breakdown-oriented’ or reactive asset management is likely to result in unreliable plant and increased human and financial risks.

As businesses mature in their approach to asset management, they progress from a breakdown-oriented approach, through reactive and corrective approaches, towards preventive, predictive and proactive approaches.

Best-practice asset management focuses on reducing risks and improving condition and performance to get the best results. It is driven by strategy and responds to the market, empowers the workforce and makes workers accountable, and always puts safety first. It also needs to be flexible enough to accommodate the individual characteristics of different hydropower stations.

Save time, save money, save lives

Specialist power and water consulting firm Entura thoroughly understands the complexities and benefits of asset refurbishment, upgrade, modernisation and extension of life.  As part of Hydro Tasmania, Australia’s largest renewable energy producer and water manager, Entura has day-to-day experience of the challenges of maintaining and upgrading assets to get the best performance, reliability and economy over the long term, through dealing with 30 hydropower stations built and maintained over the past 100 years.

Entura’s asset management techniques are based on condition, performance and risk – designed to save companies time and money. This approach is underpinned by an optimised system that combines reliability-centred maintenance (RCM) and failure modes and effects analysis (FMEA) using generic failure mode databases that can be applied to various different assets with quick results.

Entura’s asset management approach has helped other asset owners across Australia, New Zealand, Papua New Guinea and Malaysia to reduce their costs, reverse declining reliability, obtain better returns through increased performance and improved technology, increase personnel safety, decrease fire and flooding risk and other hazards, increase skills of their staff, and ensure the long-term viability of their valuable infrastructure.

Three steps to best-practice asset management

Entura’s approach to best-practice asset management has three steps that fully consider your assets’ past, improve their present operation and risk profile, and position them for their best possible futures.

Step one: Assessing assets

To fully assess an asset, we undertake detailed inspections and consider the four parameters of:

• condition (observed and measured condition, and maintainability, which takes into account the availability of spare parts, technical ability, and industry compliance)
• performance (both capability and reliability)
• confidence (the level of detail or rigour of the assessment)
• remaining useful life (an estimate of the rate of deterioration of the asset, indicating where the particular asset is on its lifecycle curve, and whether a refurbishment or upgrade can improve its position on this curve, even effectively returning it to as-new condition).

We present a high-level ‘water-to-wire’ summary of the condition and performance assessment results that quickly and graphically displays the known asset condition and remaining useful life, and identifies components for which the condition is not adequately known.

Step two: Developing a risk and mitigation plan

Once an asset has been fully assessed, we develop a risk and mitigation plan.

First, we gather and review a comprehensive set of information on the operation, design and construction of the station and its assets. We explore both the asset history and generic databases to determine probable failure modes.

Once we’ve gathered this information and analysed it against the requirements of the power station, we report the known condition of the plant in terms of business risk and develop practical and cost-effective mitigation strategies to reduce risk to a level that is both achievable and acceptable for the business.

We identify and undertake mitigation actions including ‘quick wins’ (actions that can be undertaken quickly and easily to achieve major improvements) and immediate priority activities to reduce risks. We also detect assets or components that need further investigation.

Step three: Optimising future performance (tailoring the balance)

Best-practice asset management takes a broad view of the life and operation of an asset, not only reducing immediate risks, but also promoting long-term efficient performance and sustainability. Our approach optimises the capital and operational costs over the remaining life of the asset.

A valued part of Entura’s asset management approach is our ability to offer a review of likely efficiency and capacity gains, and other general suggestions for improving performance and systems.

An important step in our holistic approach to achieving long-term safety, reliability and efficiency is training local hydro operators to fill any identified skill gaps and better safeguard the maintenance of assets. We build the capacity of our clients through on-site or formalised training through our Entura clean energy and water institute.

If you would like to discuss how Entura can assist you with assessing your hydropower plants or other power or water assets to minimise risk and maximise efficiency and useful life, please contact Ambrose Canning on +61 3 6245 4212 or Shekhar Prince on +61 412 402 110.

About the author

Ambrose Canning is Entura’s Principal Consultant, Mechanical Engineering. He has more than 30 years’ experience working on hydropower and water infrastructure projects in Australia, New Zealand, Malaysia, Papua New Guinea, India, Nepal, Philippines and Indonesia. He specialises in all aspects of hydropower development and redevelopment, upgrade and rehabilitation. He also has expertise in aspects of water infrastructure, such as dam electro-mechanical and hydro-mechanical equipment, pipelines, valves, pumps, screens, gates, valves and bulkheads.

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ADAPT, OR DIE? SWIMMING AGAINST THE DEATH SPIRAL

Many countries are experiencing huge increases in distributed generation.  Utilities are wondering whether it’s a blessing or a curse.

Electricity customers who have the funds and space to install distributed generation can reap direct benefits.  Governments are variously over- or under-incentivising the growth of distributed generation, particularly solar PV on rooftops or in backyards.

There’s talk of death spirals and the weakening or undermining of the electricity supply establishment.  Although I don’t buy all of the hype around the death spiral, it is real to an extent, and its implications present both opportunities and pitfalls.

Let’s look at the death spiral …

The ‘death spiral’ is the idea that as distributed generation and storage (such as solar PV and battery technologies) become cheaper, it becomes expedient for customers to disconnect from the electricity grid.  As more customers leave, the sunk cost of the grid infrastructure must be borne by fewer customers. And so, it becomes expedient for a wider set of customers to disconnect, and so on until (potentially) no customers are connected and the asset owners are left with a huge white elephant.

This hypothesis of the death spiral is sound so long as the following assumptions hold:

• all customers can afford to leave the grid
• the electricity supply industry is a monolith that can’t adapt to changing market conditions.

Can all customers afford to leave the grid?

It’s hard to imagine that people living in high-density housing could get access to enough high-yield solar surface area to be able to be energy self-sufficient.  This is especially true in less sunny climates with long periods of time in which proper access to sunshine cannot be guaranteed.

Additionally, can we imagine a time when the owners of rental properties install solar PV and batteries to attract tenants, especially at the low end of the rental market?

What about the high-volume users who supported or provided the impetus for the development of the centralised generation model in the first place?   While they can choose to relocate to other regions for more competitive electricity tariffs, it is unlikely that they can go off-grid to any large extent.

Is the electricity industry really incapable of adapting?  

Time will tell.  This is complicated by government regulation and conflicts of interest or conflicting policies.  Just as it is easy to accept that an economic imperative will drive off-gridding, isn’t the converse true?  Off-gridding creates an economic imperative for the electricity supply industry to adapt.  So that should convert the death spiral to some sort of controllable glide path for most.

What’s happening with load growth?

We can see that neither of the assumptions supporting the death spiral are as true as the doomsayers would have us believe.

But there’s another issue we must consider:  load growth.  Australia is in a period of flat or negative load growth at the moment, perhaps due to the decline in manufacturing, the increased adoption of energy efficient appliances and other responses of consumers to price signals such as reducing use.

Manufacturing can only decline so far. Unless our demand for electricity can sustainably decline as well, energy efficiency can only decrease demand so much.  If we imagine that our population will continue to grow, it is reasonable to assume that eventually demand will trend upwards again.

Can we imagine a future with no electricity grid?  

We can and have removed the need for fixed-line telecommunications, but energy is a trickier beast.

While we still have large industrial power users remote from generation sources, and until all customers are able to generate and store according to their own requirements, some need for a power grid remains.

The grid of the future may not look like the one we have now.  It may not be as reliable as the one we have now.  The convenience and efficiency of sharing the cost for reliable reticulated power, however, is the one thing that the grid provides that distributed generation and storage may not.

What does this mean for the electricity industry now?

It means that we need to develop the ability to adapt.

This adaptation cannot be a purely defensive approach that tries to entrench the status quo. We must turn the challenges that confront us into opportunities to do business better.

Some concrete examples of successful adaptation could include:

• using distributed generation and storage to reduce network extension costs to new loads
• using our knowledge to inform regulators and governments of the implications of existing or proposed policies
• strategising about what enabling technologies could mean to our existing market offerings
• staying relevant by adopting and embedding these technologies to add value to our customers’ lives or businesses.

Adapting in practice

Specialist power and water consulting firm Entura has already demonstrated its innovative approach to some of these issues through the King Island Renewable Energy Integration Project and other small grid and off-grid projects. This work has given us practical experience of many developing technologies such as dynamic battery charging control, distributed or device-level demand-side management.

As part of Hydro Tasmania, Australia’s largest producer of renewable energy, we’ve also directly experienced how renewable generation can maximise benefits.

In my next article, I will explore the network benefits that may be realised from working with, rather than against, embedded and distributed generation. Subscribe to our newsletter to receive my next article.

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

About the author

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

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The hidden risks in hydropower projects

Hydropower is increasingly becoming a major source of renewable energy for emerging markets throughout Asia.

Managing the not-so-obvious risks associated with developing and operating hydropower schemes is often a key challenge in securing project finance and gaining or maintaining a social licence to operate.

“Power projects, especially in developing countries, are increasingly scrutinised by international financing organisations when providing project funding” said Dr Eleni Taylor-Wood, Principal Consultant, Environmental and Social Science at specialist power and water consulting firm Entura.

“These entities, such as the Asian Development Bank, the International Finance Corporation and the World Bank, recognise that growth must be both inclusive and environmentally sound to reduce poverty and build shared prosperity for today’s population and future generations.”

Managing risk across all stages of a project can improve the viability of a project and the overall project outcomes.

What are the risks?

It is critical that both governments and hydropower entities understand the opportunities and risks of major projects, not only at the development stage, but also throughout the ongoing operation and management of the scheme.

Typically, some of the key risks to be considered include:

• Is there an identified need, what is the future demand, and is there a market?
• What is the best energy option?
• Could any political or public sector issues affect the project?
• Is there the institutional capacity to advance the project?
• How available is the resource? Will climate change affect availability?
• Is the site appropriate? Are there other options?
• Can you connect into the grid, and where? What systems enhancements might be required?
• Who are the key stakeholders and how can they be engaged?
• What are the possible environmental and social impacts, and how can they be avoided, mitigated, offset or compensated?
• What safety issues are associated with development, construction and operation, and how can they be managed?
• What are the ongoing operational costs?
• What are the ongoing operational requirements, such as compliance requirements, condition assessments, performance monitoring, maintenance strategy and planning, and training to build operator skills?
• How will you manage unforeseen stakeholder, technical, financial, social and environmental issues?

Using international standards and sustainability assessment frameworks to manage risks

International standards and sustainability assessment frameworks can help guide a comprehensive review of risks and, in some cases, identify further opportunities to increase positive outcomes from projects.-

In 2010, the International Hydropower Association launched the Hydropower Sustainability Assessment Protocol, a framework for assessing the sustainability of hydropower projects across the world. This framework can be used to help guide a hydropower project from the early stages of consideration through to operation, identifying issues and gaps for consideration, as well as be used to assess the project’s sustainability performance.

There are only eleven accredited assessors able to officially apply the Protocol worldwide. Entura’s Dr Eleni Taylor-Wood and Dr Helen Locher are among this select group of accredited assessors, having undertaken assessments of hydropower projects in Europe, South Asia, South-east Asia and South America.

One step at a time

“Evaluating the risks in stages means that the cost of evaluation can be minimised should the project be judged unviable at any point. Not all risks can be avoided, but many can be minimised or mitigated,” explained Dr Taylor-Wood.

Early identification of key risks allows companies to manage these risks throughout a project, minimising corporate, technical, environmental and social impacts and their associated costs, including damage to corporate reputation should an unmanaged risk develop into a crisis.

Self-assessment and capacity building

“I believe that for hydropower developments to be sustainable, we need to use the lessons of the past to innovate in the present and protect the future,” said Dr Taylor-Wood.

“This means learning from mistakes and carefully assessing and managing technical, corporate, economic, environmental and social risks right across the project lifecycle, so that developments contribute positively to social, environmental and economic goals.”

Entura uses a unique, tailored self-assessment tool to assist power companies and developers to understand the risks and opportunities facing their projects and to build capacity to assess, monitor and report on those projects.

This tool is based on the assessment criteria identified in guidelines and standards such as the Hydropower Sustainability Assessment Protocol and those used by the International Finance Corporation.

In addition, it can be adapted to include other standards or to assess compliance with criteria relevant to a client’s requirements or obligations (such as internal policies and/or permit or concession conditions).

Benefits include easier access to finance, better ability to anticipate and respond to stakeholder concerns, and avoidance of delays and problems through the project development pipeline.

Entura provides expert advice to help clients:

• develop a better understanding of risk identification, assessment and sustainability, across all project stages
• self-assess a project against recognised guidelines and standards to identify whether key issues, risks and opportunities have been considered and identify potential gaps for further consideration
• meet international financing requirements
• assess viability or conduct a due diligence of a project
• undertake assessments against the Protocol
• address risk issues to improve the overall sustainability performance of projects
• build institutional capacity to develop, operate and/or maintain power schemes.

eleni.taylor-wood@entura.com.auIf you would like to discuss how we can assist you with assessing your project or how you can assess and track your own progress towards improved risk minimisation and sustainability, please contact Dr Eleni Taylor-Wood on +61 3 6245 4582 or Shekhar Prince on +61 412 402 110.

About the author

Dr Eleni Taylor-Wood is Entura’s Principal Consultant, Environmental and Social Science. Eleni has 20 years’ experience successfully managing large-scale, complex projects that run over several years, as well as providing expert advice and independent review for a range of infrastructure and planning projects. She has worked on projects around the world including in Australia, Mozambique, South Africa, Iceland, Colombia, India, Malaysia, Mekong, Solomon Islands, Fiji and Papua New Guinea. Her experience covers a vast gamut of studies including: environmental and social impact assessment and management; strategic management of wetlands and waterway; feasibility and approvals for new hydropower projects, environmental flow determination and assessment, and sustainability assessments. Eleni is currently one of eleven Accredited Assessors under the Hydropower Sustainability Assessment Protocol worldwide.

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