The Australian Government has announced a $2 billion expansion to the Snowy Hydro scheme, involving new tunnels and pumped hydro storage, designed to help stabilise electricity supplies.
The Australian National University (ANU) has experts who are available to comment on the announcement.
Professor Ken Baldwin, Director, ANU Energy Change Institute
"The announcement of a revitalised Snowy Hydro scheme for energy storage is welcome, and comes hard on the heels of the South Australian Government's recent energy initiative that also incorporates storage. However, what is urgently needed is a national energy plan for these initiatives to plug into.
"The energy sector has been paralysed by a decade of government policy uncertainty, and is now creaking under the strain as technological advances overwhelm it. The Chief Scientist Alan Finkel has been given the task of reviewing the National Electricity Market, and will soon be handing down his report, following which a serious national discussion needs to take place.
"The national energy plan needs to take account of our climate and environmental challenges, and needs to focus on decarbonising the energy sector by the middle of the century. This should be the driving consideration, along with delivering affordable and secure electricity supply.
Providing more pumped-hydro storage by enhancing the Snowy Scheme is one part of securing supply. It will take energy generated elsewhere - potentially by renewables like wind and solar when they are in plentiful supply - and store it by pumping water from an existing dam uphill to another existing dam using new tunnels. At times of high peak demand when energy systems are under stress, the water is then released from the higher dam and flows downhill through the same tunnel to electricity turbines at the lower dam that then generate electricity. The efficiency of this cycle can be as high as 80 per cent, and involves little loss of water to the environment."
Professor Andrew Blakers, ANU College of Engineering and Computer Science & ANU Energy Change Institute
"Pumped hydro energy storage (PHES) is the 97 per cent worldwide market leader in energy storage because it is much cheaper than alternatives. The announcement of increased PHES in the Snowy Mountains is welcome.
"Deployment of wind, solar photovoltaics (PV), pumped hydro energy storage and increased high voltage (HV) interconnectors between the states allows the National Electricity Market to reach 100 per cent renewable electricity with high reliability and at zero net cost. Wind and PV will replace retiring coal and gas plant at lower cost than the alternative replacement (new coal and gas).
"Wide distribution of wind and PV from Queensland to South Australia and everywhere in between to access different weather, coupled with increased HV interconnection and PHES, confers high reliability at modest cost. Any desired degree of grid stability can be achieved at modest cost by adding more PHES at multiple locations.
"A clear retirement schedule is needed for existing coal and gas power stations to allow for smooth uptake of PV and wind. This retirement schedule should be consistent with the national emissions reduction target. Retirement could be accomplished through carbon pricing, an emissions intensity scheme or similar."
Dr Evan Franklin, ANU College of Engineering and Computer Science & ANU Energy Change Institute
"The announced expansion of the Snowy Hydro scheme, adding up to 2 GW of additional power capacity, is a positive move along the path towards high penetration renewable generation in the National Electricity Market.
"While the project itself will not create additional long-term renewable energy generation, since expansion of water storage reservoirs is off the table, it will undoubtedly facilitate the increased rollout of renewable technologies such as wind and solar, by storing energy when those generators are producing at high levels and dispatching it later to meet demand when wind and solar generation output is low.
"Importantly, projects such as this can potentially provide much-needed security and stability services to the power system, at a level which conventional generators are typically unable to provide, particularly in the rapidly changing energy market environment. The level and degree to which this project will be able to provide that power system stability, including ensuring supply / demand balance on a second by second basis, will depend upon the choice of pumped hydro technologies that are utilised and the way in which they are operated. However, with recent events firmly in mind, I would expect this to be a priority that the announced feasibility study will squarely address.
"In the broader context of facilitating high to very high penetration of affordable and secure renewable energy generation in the world's future electricity generation mix, I believe projects such as this, supported in parallel by both grid-scale and distributed battery storage and the unprecedented flexibility and responsiveness that this technology provides, should and will play a key enabling role."
Dr Jamie Pittock, ANU Energy Change Institute
"Re-engineering the Snowy Hydro Scheme to provide greater energy storage is a great move for supplying non-polluting electricity to the grid. This will enable much greater use of wind and solar power generators on the national electricity grid. Physically the Snowy Mountains are one of the best places in Australia to do this because of the great changes in elevation and potential to better use existing dams.
"It is also good to see former climate change and renewable energy skeptics embracing an off the shelf technology that enables wind and solar generators to provide base load power.
"However the proposed hydro development is located in Kosciuszko National Park a very environmentally sensitive alpine area. Construction of infrastructure like tunnels, power stations and powerlines inevitably has environmental impacts. The state and federal governments must ensure that the project results in an additional environmental dividend.
"To balance the socio-economic benefits with the environmental impacts of the Snowy 2.0 proposal, scientific oversight is required to provide independent advice to the Federal and NSW governments, for example, through reinstating the Snowy Scientific Committee that was axed by the NSW Government in 2014."
Professor Frank Jotzo, ANU Crawford School of Public Policy
"Large scale pumped hydro electricity capacity is exactly what will be needed to fully integrate increasing amounts of wind and solar power into the electricity grid. It means being able to store excess renewable energy and release it when it is needed.
"Australia has the opportunity to move to a fully decarbonised power system, as ageing coal generators are replaced with renewable energy that is plentiful and increasingly cheap. New pumped hydro capacity in the Snowy Mountains can be part and parcel of this, alongside smaller electricity storage in other parts of the country and batteries in homes and businesses.
"Pushing for the snowy expansion is an unusually bold and forward looking initiative in the context of Australia's energy and climate policy over recent years. It could be difficult to keep project costs under control while building it quickly, as a state owned project. But it is fundamentally the right thing to do."