Storage of pumped hydroelectricity is experiencing a renaissance

In Vattenfall’s central control room, human operators, aided by algorithms, monitor the power grid, and the market, to judge whether their pumped hydro plants should generate or pump. Kuehne adds that the frequency of alternating between these modes has increased over time due to the volatility of renewable energy sources.

However, if you can get the right response, you can earn a lot of money. On its website, Vattenfall describes hydropumping as “extremely profitable.” A study published last month estimated the impact of the rise of renewables in Spain between now and 2050. With electricity prices gradually falling, volatility rising, and the need to import electricity generally declining, the authors found that energy storage will be used 12% more in the future – and that a system that combines renewables with pumped hydro storage will see its profits rise.

“Most countries in the world have the right geographic areas for it,” says Rosie Madge, a systems engineer at Energy Systems Catapult, a non-profit research and innovation center.

A report by Madge and colleagues, published in October, scored 11 countries for their suitability for pumped water and other long-term energy storage technologies. As for the two countries that were famous for superficiality, Denmark and the Netherlands, they performed poorly. But the other systems were all well suited to conventional pumped hydro, and a few, including the UK, Australia and China, were well suited to the high-density version. The results were based partly on each country’s readiness and desire to deploy the technology, and also on market conditions.

But even in this analysis, it was traditional pumped hydropower that seemed the most deployable overall – when compared to many other long-duration storage technologies including high-density pumped hydro, hydrogen, ammonia, metal-air batteries, compressed air, and unpumped hydrogravity storage.