It’s like putting money in the bank so you can spend it later.

Brian Murray is director of real time operations with the California Independent System Operator, which runs the state’s electricity grid. He said battery storage brings to the grid a crucial element. Energy flexibility.

“It’s not like a steam plant that needs ten hours to turn on,” Murray said. “Batteries are essentially always on. They can be discharging and providing energy to the grid or they can be consuming energy while they’re charging.”

He said battery storage is already a major player in the state’s energy system that will become even bigger as California aims to create an emission-free energy supply system by 2045. New research shows a path to that goal that’s paved with a lot of stored energy.

“As we are decommissioning coal plants and natural gas plants, that type of technology of solar and wind storage can come up on line and help us get to a zero-emissions future in the decades to come,” said Patricia Hidalgo-Gonzalez, with the Center for Energy Research at UC San Diego.

Hidalgo-Gonzalez is one of the authors of an article published in the journal Nature that examines the value of long-duration energy storage to the electric grid of the future.

She said California’s renewable energy sources, dominated by solar and wind, are periodic. They’re not always shining or blowing but energy storage can solve some of that problem.

“From noon to 2 or 3 p.m. we have an excess of solar power production and we just waste it, in practice. But if we would have more storage we could take advantage of that free electricity, and store it for the hours of the evening when we have the high demands and the highest prices of electricity,” Hidalgo-Gonzalez said.

The article in Nature said a decarbonized grid with more storage capacity would decrease variability of energy supply and reduce energy prices up to 70%.

Hidalgo-Gonzalez said another good storage scenario is storing hydropower in the spring for use during the dry summer. But can we store power for months? She said hydrogen technology can.

“You can store hydrogen in tanks. It’s fuel basically that you’re storing (energy) in. And then you can use it when you need it the most. So that can support that seasonality aspect,” she said.

Hidalgo-Gonzalez said hydrogen storage technology is available but it needs to come down in price to become practical.

An important part of the new research, she said, zeros in on finding cost targets for different storage technologies, as a guide for companies that would develop them.

On the policy side, she hopes governments will begin to mandate energy storage, in order to be sure we see its benefits in the future.