The U.S. Department of Energy announced recently that it’s awarding a $1.25 million grant to a project team from GE Research and GE Energy Consulting to dig deeper into the possibilities of hydro storage, a promising technology that might increase the reliability and availability of renewable energy sources like wind and solar.
Without storage, renewables can be used only as they’re being generated, which is to say: when the sun shines and the wind blows. By making low-carbon energy available during the off-hours, hydro storage — which relies on gravity, a force as old as the universe — might ease its integration into the electrical grid.
Storage can also help balance the grid, which resembles a giant seesaw that must remain in a perfect equilibrium. For it to work, production must constantly match demand. Hydro storage can quickly soak up excess energy and release it on demand.
Here’s how it works: Also known in the U.S. as pumped storage hydropower (PSH), hydro storage is essentially a giant battery in the shape of a dam. Pumped storage hydroelectric plants require two reservoirs located at two different elevations, linked by tunnels that move water between them. When solar panels and wind turbines are generating electricity to spare, grid operators can use some of that juice to pump water uphill to a high reservoir. Later, when demand for energy jumps, they can release the water and use it to generate power by sending it downhill through hydroelectric turbines. That’s making hydro storage a natural fit for countries seeking to boost the share of renewables in their energy mix. In places like Uruguay, which already gets half its electricity from just four hydroelectric dams, and most of the balance from solar and wind generation, hydro storage may push the country over the line toward 100% renewable energy.
The technology might help the U.S. increase its access to renewables too — that’s what the GE project team, with support from hydro teams at GE Renewable Energy, is seeking to find out with the new government grant. “Can PSH prime the pump to enable more renewables? This is a central question we’re asking as part of our DOE-supported study,” said Yazhou Jiang, a GE Research project leader. “It’s part of a mix of promising storage solutions that are emerging to meet the needs of a fast-changing energy landscape.”
To be sure, hydro storage is not a new technology. “But the need for it is increasing now that two-thirds of the world’s future energy mix will come from renewables,” Bill Armstrong, regional leader for GE’s Hydro Solutions in Europe, Middle East and Africa, said at the World Hydropower Congress in Paris a couple of weeks ago. Though the technology is practically elemental, GE is also looking at digital tools — similar to the Reservoir, a platform of battery-based energy-storage solutions launched last year — that will optimize the performance of PSH projects.
“We’re testing the hypothesis that at high levels of wind and solar, you will need a storage portfolio,” said GE Energy Consulting senior technical director Debra Lew. “This project will help to value the benefits of pumped storage hydro to the grid.” The study will be completed over the next 18 months.