Finding viable sites for pumped storage hydropower used to be tricky, but now there’s a map for that thanks to researchers at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL).

Pumped storage hydropower systems are constructed by connecting two reservoirs, one at a higher altitude than the other. The plants pump water uphill, storing it in the upper reservoir, before releasing it down through a turbine, which spins a generator and pumps energy back into the grid. These systems already provide 93 percent of the U.S.’s grid-scale energy storage. In today’s hotter, more volatile climate, they can replenish electricity during blackouts caused by heatwaves, hurricanes, or cyber attacks and keep renewable energy flowing when the sun sets and winds do not blow. In short, they make the power grid more resilient. While little data has existed on where pumped storage hydropower plants could be built, NREL researchers developed a map that depicts locations that hold the greatest future potential for these facilities. “With this map, people who live in Wyoming could zoom in on a mountain range and see where some of the best sites are,” said Stuart Cohen, a model engineer at NREL and a co-author on both reports. While the first data release relies on fixed parameters, the researchers plan to build an updated version of their map that gives users more control. “We want to build an interactive map where you can check boxes on and off to choose between 12-hour or 8-hour storage, 40-meter or 60-meter dam height. Whatever people want,” said Cohen. Read more at NREL.