ENERGY SECURITYHow giant “batteries” in the Earth Could Slash Your Electricity Bills
We’re wasting too much of the clean energy we generate. Reservoirs and caverns can store excess solar and wind power.
Solar panels and wind turbines give the world bountiful energy — but come with a conundrum. When it’s sunny and windy out, in many places these renewables produce more electricity than is actually needed at the time. Then when the sun isn’t shining and wind isn’t blowing, those renewables provide little to no electricity when it’s sorely needed.
So for the grid of tomorrow to go 100 percent renewable, it needs to store a lot more energy. You’ve probably heard about giant lithium-ion batteries stockpiling that energy for later use. But when providing backup power, even a big battery bank will usually drain in four hours. The need for an alternative has the United States government, researchers, and start-ups scrambling to develop more “long-duration energy storage” that can provide a minimum of 10 hours of backup power — often by using reservoirs, caverns, and other parts of the landscape as batteries.
A new study from several universities and national labs in the United States and Canada shows that large-scale deployment of long-duration energy storage isn’t just feasible, but essential for renewables to reach their full potential, and would even cut utility bills. It looked specifically at the Western Interconnection, a chunk of the grid that includes the western U.S. and Canada, plus a bit of northern Mexico. The study found that building more long-duration energy storage there would reduce electricity prices by more than 70 percent in times of high demand.
“It’s like an orchestra,” said Patricia Hidalgo-Gonzalez, director of the Renewable Energy and Advanced Mathematics Laboratory at the University of California, San Diego and co-author of the paper published last month in the journal Nature Communications. “We need to think about all these factors, how they work. But bringing in more storage can only help in making this more cost-effective.”
The technologies already exist to hold renewable energy for at least half a day, with more on the way. One technique is known as pumped storage hydropower: When the grid is humming with renewable power, a facility pumps water uphill into a reservoir. Then, when solar or wind power drops off, the facility lets the water loose to flow back down into another reservoir, turning turbines that produce electricity. It’s exploiting energy from the wind and the sun, along with the power of gravity.
