Gaining greater insight

A new report published by the Clean Energy Council in November 2021 outlines the enormous potential, as well as the key challenges that will need to be overcome, for Australia to deliver the 19GW of dispatchable energy required by 2040 to replace retiring coal-fired power stations.

"Hydropower is one of the most mature forms of renewable generation," says Clean Energy Council Chief Executive, Kane Thornton. "Its large energy storage capability and the essential system services it provides leave it ideally placed to thrive in a 21st-century energy system to complement the rollout of wind, solar and battery storage and drive the reliable and secure decarbonisation of the Australian energy sector.”

Hydropower has been the foundation of Australia’s renewable energy sector since 1914. The first Australian hydropower plant was developed in 1895, with most assets built between 1951 and 1996. Today, there are 8.5 GW of hydropower assets in operation across the country, which represented approximately 13 per cent of national capacity in October 2021 and 23 per cent of Australia’s renewable generation in 2020.

Earlier in November 2021, the New South Wales government revealed that its A$50 million Pumped Hydro Recoverable Grants Programme had received 11GW of proposals or over five times the 2GW it needs to support wind and solar projects within the state's renewable energy zones. Thornton says that this is further evidence of strong investor appetite under the right policy settings.

Market signals are not only critical to support the development of new capacity, they also provide existing hydropower assets with the confidence to refurbish and modernise to ensure that they are fit-for-purpose in a high renewables future. With long lead times for the development and refurbishment of hydropower assets and the deployment of wind and solar outpacing even the most ambitious official assumptions, the report says it is critical that policy makers work with the hydropower sector to design and implement policy approaches that can unlock new hydropower investment, including strategic transmission investment such as the Marinus Link and Hume Link.

The report adds that hydropower and pumped storage hydro can be an economic boon and creator of employment opportunities for regional communities. Today, hydropower and pumped storage together employ around 2500 people in Australia or 10 per cent of the renewable energy sector workforce. With the right support, the Clean Energy Council says hydropower in Australia can continue to create thousands of jobs today, while underpinning the reliability of the grid for generations to come.

Urgency 

A strong sense of urgency was shared by more than 300 participants at the 2021 Canadian Waterpower Week, hosted by national trade association WaterPower Canada during October.

“We’ve got less than a decade now to meet ambitious and essential emissions reduction targets, and our industry is ready to play what can only be an instrumental role,” said Anne-Raphaëlle Audouin, President and CEO of WaterPower Canada. “But what the conference also highlighted is the need to move from targets to action.”

“The world needs an accelerated energy transition going forward, and hydropower has to play a key role,” agrees Dolf Gielen, Director of Innovation and Technology at the International Renewable Energy Agency. “We need new hydropower capacity, but also we need modernising and upgrading of the existing hydropower capacity. Flexibility and storage systems of hydropower can complement solar and wind going forward, and sustainability of hydropower is key in this development.”

“At Statkraft, we have been doing hydropower for the past 100 years. Given the energy transition, in addition to new renewables, we have to look into the existing fleet, and look into hydropower that will play a big role in the market of supplying zero emission generation and power going forward,” said Hilde Bakken from Statkraft. “Another big responsibility is making sure that we are developing transmission across. I think it’s important for policymakers not to become too national because then you’re not solving the problem.”

“It’s interesting when you look at the role that hydro historically has played. Certainly, in Ontario hydro is synonymous with electricity,” says Nicolle Butcher, Senior Vice President of Renewable Generation and Power Marketing at Ontario Power Generation. “That legacy is what we need to build upon. There are really three elements that we’re working on at OPG. That’s maintaining our current assets, so how to refurbish them in a way that allows us to ensure that they’re going to be there for the next 100 years. The second thing we’re working on is highlighting the expansion of hydro, so how can hydro help from a storage perspective, or how does hydrogen play with hydro. And then finally building new. So whether it’s completely redeveloping some of our old sites, or building new greenfield sites. Those are critical elements that we’re going to develop more in the coming decades to be able to address climate change.”

Diversity

Michelle Branigan, CEO at Electricity Human Resources Canada is keen for the water industry to learn about and help overcome the main barriers to diversity, equity and inclusion (DEI).

“They are more than HR buzzwords,” she says. “They’re essential policies for the long-term health of any professional organisation, including waterpower utilities and their suppliers.”

Many industries, including hydropower and the electricity space, haven’t really kept pace with demographic changes across Canada. Historically, Branigan says that the electricity industry has long been very male dominated and very slow to embrace change. Research undertaken in DEI “tells us barriers to entry for under-represented groups are still alive and well in this industry”. It’s starting to get a bit better but there is still a lot to do that will require effort

Women only represent 26 per cent of the electricity sector in Canada. In the trades this drops to under seven per cent, and even in senior leadership positions only 25 per cent of roles are taken by women. Indigenous people working in the electricity sector hovers at just over four per cent, and a high concentration of that is in the trades. People with disabilities are less than three per cent of the workforce, and only 15% of the electricity industry is internationally trained workers, compared to 25 per cent for all other industries. 

Branigan says it’s the same for visible minorities — really low numbers which haven’t changed much over the last decade.

So, what kinds of barriers do under-represented groups face?

• Barriers on the retention side can be structural, within the organisation, or social (inequitable pay compensation is one example).
• Barriers to entry can occur right at the job interview. Unconscious bias can lead to hires that reflect the makeup of the hiring committee, rather than a candidate that has been evaluated and hired solely on their skills and competencies.
• Language can be a barrier as well, when job descriptions are outdated and list requirements that really are not essential to the job, such as a driver’s licence. That could be one barrier for Indigenous people in remote regions who have never had to obtain a licence.
• Perception is important and there are still many communications barriers. If somebody looks at a company website or annual report and doesn’t see anybody who looks like them, they’re extremely unlikely to see themselves having a successful career in that organisation.
• Education and the ability to access career information can be another barrier. A lot of the utilities are working with high schools and even elementary schools to try and build career awareness amongst young people so they are aware of the possibilities out there that exist. And that must include messaging that says everyone is welcome.

It is really important that companies adopt formal policies and practices directly aimed at measuring the impact of the approaches they’re taking to developing DEI. There has to be disclosure and reporting that establish clear metrics to measure progress over time.

“It’s absolutely critical that there’s buy-in from the very top. We need to move from awareness and shared understanding to actual commitment,” Branigan continues. “I really believe that we have an ethical obligation to ensure that anybody in our society feels capable of pursuing a career regardless of their gender, their background, or any other parts of their identity. As a sector, we are better when everybody can participate. And that’s why the diversity and inclusion work is so important.”

Michigan failures

On 19 May 2020, the Edenville and Sanford Dams, located in central Michigan, US, failed. To investigate the failures and the physical and human factors that contributed to them, the Federal Energy Regulatory Commission (FERC) engaged a five-member independent forensic team (IFT) in August 2020.

In September 2021, the IFT announced it had essentially completed its evaluation of the physical mechanisms of the dam failures. Although its work and final report will not be completed for several months, the IFT wanted to share its findings with the dams profession and the public. 

The Edenville and Sanford Dams were two of four dams in Michigan owned at the time of the failures by Boyce Hydro Power and located in series along the Tittabawassee River; the other two Boyce Hydro dams are Secord Dam and Smallwood Dam. All four dams were built in the 1920s. At the time of the failures, Secord, Smallwood, and Sanford were active hydroelectric facilities. Edenville’s powerhouse was inactive because its FERC license had been revoked in September 2018. 

The watersheds upstream of the four dams received significant, but not extreme, rainfall from 17-19 May 2020. Despite all spillway gates being open, lake levels continued to rise. Wixom Lake which is impounded by the Edenville Dam, continued to rise until the time of the failure when the lake level is estimated to have been about 1.6m above normal pool level and 0.3-0.45m below the nominal embankment crest. 

Based on a video recorded by a local resident, photographs, and eyewitness accounts, it became clear that a downstream section of the Edenville dam failed suddenly. The failure section was 12-24m wide and located in the left embankment. An upstream remnant remained standing for 10 to 20 seconds, before it gave way and the embankment was fully breached. The breach enlarged over the next few hours, releasing the water stored in Wixom Lake. 

The IFT is confident that the embankment did not overtop. Internal erosion was also judged to not be plausible as the primary mechanism of failure because the observed physical characteristics of failure are not consistent with this: 

• No seepage exiting the ground surface was detected. 
• No turbid water discharge was detected. 
• No evidence of a developing open pipe, sinkhole, or progressive sloughing that might indicate global backward erosion piping was observed. 
• The kinetics of the failure are not consistent with historical observations of internal erosion failures. 

In the IFT’s opinion, internal erosion may have contributed to the depression in the crest that was observed about 35 minutes before the failure and may have affected the phreatic surface and pore water pressures within the embankment, but it does not explain the primary physics of the failure. 

In the IFT’s opinion, the most plausible principal mechanism for the failure of Edenville Dam is static liquefaction (flow) instability of saturated, loose sands in the downstream section of the embankment.

Static liquefaction has been receiving increasing attention in recent years in the tailings dam arena because of several recent tailings dam failures. This failure mechanism has been rare, but not unprecedented, for water storage dams, and water storage dam engineers have not typically considered it. 

The conclusion regarding static liquefaction at Edenville Dam is supported by:

• The accelerations and velocities of the failing soil mass evident in the dam failure video.
• Strong evidence of loose, uniform fine sand in the embankment.
• Strength loss behaviour exhibited in laboratory tests on loose specimens of uniform sand collected from the breach remnant.
• A reasonably close match of a simplified kinetic analysis with the characteristics of the failure shown in the dam failure video. 

Although there is uncertainty concerning the exact trigger or triggers that led to the static liquefaction failure, there are several phenomena that are plausible triggers, either individually or in some combination, as explained in the report.

The physics of the Sanford Dam failure are very clear and was the result of embankment overtopping. The breach outflows from Wixom Lake after the failure of Edenville Dam caused the water level in Sanford Lake to rise more quickly than could be accommodated by the spillways at the Dam. Given the failure of Edenville Dam, the failure of Sanford Dam was not unexpected. Regulators and engineers understood that should a breach occur at Edenville, Sanford would almost certainly be overtopped and fail.

South Carolina reports

Since 2015, a series of historic weather events have caused more than 80 state-regulated dams across the US state of South Carolina to fail, driving a renewed awareness of dams and their risks to public health, safety, and welfare. 

In September 2021, the South Carolina section of the American Society of Civil Engineers (ASCE) prepared its first report card on infrastructure. Every four years, ASCE’s Report Card for America’s Infrastructure depicts the condition and performance of American infrastructure in the form of a school report card—assigning letter grades based on the physical condition and needed investments for improvement.

South Carolina’s dams received a D grade which means they are poor and at risk. The infrastructure is in poor to fair condition and mostly below standard, with many elements approaching the end of their service life. A large portion of the system exhibits significant deterioration, and condition and capacity are of significant concern with strong risk of failure.

South Carolina currently has 2294 state-regulated dams, 90% of which are privately owned and operated. Regulated dams are classified as either high hazard, significant or low hazard potential. 

High hazard potential dams have the greatest possibility of causing both serious damage to infrastructure and property, but also carry the likely risk of loss of human life in the case of a dam failure. Approximately 25% of dams in South Carolina are under this designation - more than 70% are in satisfactory or fair condition but more than 25% are poor or unsatisfactory. In addition, less than 12% of South Carolina dams are of significant hazard potential and more than 61% are of low hazard potential.

South Carolina also has 45 federal dams of which 12 are high hazard. Two of these are in satisfactory condition, four are fair, one is poor, two are in unsatisfactory condition, and three are not yet rated. There is one unrated significant hazard federal dam, plus 32 low hazard potential structures.

The average age of South Carolina’s dams is just over 60 years old, higher than the national average of 57 years old. While the age is not a direct reflection of hazard potential, ASCE says the high average age typically means that the dams were not built to current standards and may not incorporate newer materials that could be used to improve their resilience and reduce the risk to downstream areas. Nearly 80% of the existing inventory was constructed before South Carolina lawmakers established a state-wide dam safety framework. Therefore, many of these dams were constructed with little regulatory oversight or proper documentation of construction details.

Over the last two decades, South Carolina’s dam safety budget has drastically increased. In 1999, it was slightly over US$250,000, translating into approximately US$100 per regulated dam, while the budget per regulated high hazard structure was around US$1500. After the historic October 2015 rainfall and subsequent dam failures, resources were allocated to rebuild and expand the state’s dam safety programme. Since that time, more than US$12 million has been made available for engineering technical support, dam inspections, inundation mapping, and more. Now, the dam safety budget is more than US$1 million with US$453 being spent per regulated dam and more than US$1900 per HHPD. Though these values have significantly increased, they remain well below the national averages of US$738 per regulated dam and US$4875 per HHPD.

Dam safety staff also increased from less than two fulltime equivalents (FTE) to approximately 18. Accordingly, there was a significant improvement to the number of state-regulated dam safety inspections conducted per staff member. From 2011 to 2018, the number of inspections were driven down from more than 1400 per FTE to approximately 125 per FTE, now better than the national average of 189 per FTE. For HHPD, the value also fell from more than 100 per FTE to nearly 30 per FTE, very close to the national average of 29.

Ideally, all South Carolina’s HHPDs would have Emergency Action Plans but currently only 72.5% are covered, ten % below the national average.

To withstand or quickly recover from localised storms or non-weather-related events that strain South Carolina’s dams, the staff rotate 24-hour-a-day on-call shifts for the Dam Safety Technical Assistance phone line. The state says it is committed to providing engineering expertise to assist dam owners if trouble arises and to help identify the severity of a situation. This assistance is intended to determine whether local emergency response officials should be notified. To this point, the phone line assistance has enabled staff to respond to multiple occasions of after-hours dam failure emergencies.

In addition to providing technical assistance to ensure the state’s dam sector is becoming more resilient, investment has also been made in innovative modelling to improve safety planning efforts. 

Although improvements have been made ASCE recommends that to raise its grade South Carolina needs to:

• Develop emergency action plans for every high hazard-potential dam by 2025. 
• Determine sustainable sources of funding for dam rehabilitation, maintenance, and other safety projects 
• Increase state funding to the dam safety programme, including adequate staffing and resources per state-regulated and high hazard potential dam that are in line with na­tional averages. 
• Educate dam owners about the importance of keeping accurate, easily accessible ownership and operation and maintenance records.