Authored by Felicity Bradstock via OilPrice.com,

After years of neglect, the United Kingdom has big plans for hydropower as part of broader plans for a green transition. The government is supporting the development of three large-scale hydro-storage projects as part of its plans to diversify the U.K. energy mix, support a green transition, and boost energy security.

Hydropower is one of the oldest and largest sources of renewable energy. It works by converting the energy of running water into electricity. Many hydropower projects rely on reservoirs created by dams to store large quantities of water and produce electricity as needed. Meanwhile, hydropower plants without reservoirs are typically called run-of-river power plants. In these types of facilities, production is controlled by the amount of water flowing past at any given time. Just four countries – China, Brazil, Canada, and the United States – produce roughly half of the world’s hydroelectricity.

The U.K. has been producing electricity from hydropower projects since the 1800s, and the energy source now contributes around 2 per cent of the country’s electricity generation. Two-thirds of hydropower-generated electricity is produced during the winter months. There are almost 1,700 hydropower schemes across the U.K. with an installed capacity of around 2 GW.

As part of plans for a green transition, the U.K. is expected to invest heavily in hydropower in the coming years. In October 2024, the U.K. government announced a new policy to promote investment in Long Duration Energy Storage (LDES) as part of the country’s decarbonisation plans.

The global demand for energy storage has risen dramatically in recent years, as many countries shift to less stable renewable energy sources to produce low-carbon power. LDES, also known as pumped hydropower storage (PHS), is a type of hydroelectric energy storage. It works by using two reservoirs at different heights to generate power by moving water from one to the other (discharging) as it passes through a turbine. The water can also be pumped back up to the higher reservoir (recharging) during off-peak electricity hours for reuse during peak demand. The system effectively functions as a massive battery, storing power for release as required.

The U.K. government aims to diversify the country’s energy mix to reduce reliance on fossil fuels and help strengthen energy security. Having invested heavily in intermittent clean energy sources, such as wind and solar power generation, it is looking to other energy sources, including hydro and geothermal power, to fill the gap.

There are currently four PSH schemes in the U.K., all of which were funded publicly from the 1960s to the 1980s to store overnight nuclear generation. By 2025, 11 PSH were under development across the U.K., with an expected combined power storage capacity of more than 10 GW and 200 GWh, or 25 per cent of the country’s power demand, once completed. A study from Imperial College London suggests that just 4.5 GW of new PHS with 90 GWh of storage could save up to £690 million a year in energy system costs by 2050. 

Last month, the U.K. energy regulator provisionally greenlit the first major new hydropower projects in over four decades, as part of plans to reduce the U.K.’s dependence on energy imports, in response to ongoing geopolitical tensions in the Middle East and severe disruptions to energy supply chains. Three new PHS power stations will be developed in Northern Scotland, using the region’s famous lochs to supply hydropower, pending final approval.

Statera Energy’s Loch Kemp project will use water from Loch Ness, while SSE’s Coire Glas project will rely on water from Loch Lochy, which is situated between Fort William and Inverness. Meanwhile, Gilkes Energy’s Earba project, expected to be the U.K.’s largest pumped storage hydro facility, will pump water from both Loch Leamhain and Loch Earba.

The three projects are expected to be completed by the early 2030s and will be the first PHS power projects since the Dinorwig hydropower plant was completed in north Wales in 1984. Dinorwig, also known colloquially as the “electric mountain”, can generate enough electricity to power nearly 2 million homes in a matter of seconds.

The U.K. Energy Minister, Michael Shanks, stated, “Forty years after the country’s last pumped storage facility, this government is getting Britain building again. The lesson from the conflict in Iran is clear: Britain cannot afford to remain at the mercy of volatile fossil fuel markets and leave families exposed to the next price shock.”

The new hydropower projects are expected to enhance the reliability of Britain’s renewable energy and help the country reduce dependence on fossil fuels once and for all. They will help reduce reliance on energy imports, support the government’s goals for a green transition, and enhance energy security through diversification. PHS projects also provide an alternative to lithium-ion battery storage, helping reduce imports of raw materials and batteries from China.