We’ve all heard about the promise of lithium-ion batteries and the proven reliability of pumped storage. Yet, not much has been said about renewable hydrogen’s promise as a widely deployable energy storage solution.
We’ve written many times about the need to develop more energy storage solutions. Why? Because the ever-increasing volume of renewable energy flowing into the grid demands it.
Lithium-ion battery technology seems to have taken center-stage. Batteries make sense for short-term energy storage (a few hours or so). But, then what? Lithium-ion batteries will undoubtedly have a future in ensuring grid reliability, but they aren’t quite ready for primetime as a long-term energy storage solution.
Or, as Dan Finn-Foley, head of energy storage at Wood Mackenzie puts it, “Lithium-ion will probably be the dominant technology for four-hour systems.”
As we’ve discussed before, pumped hydro is the most widely used type of energy storage in the U.S. There are currently 24 permitted and operational pumped storage facilities in the U.S. with a total capacity of 16,500 MW (1 MW powers approximately 750 homes instantaneously). These facilities account for around 95% of all energy storage in the U.S.
Large-scale compressed hydrogen gas could replace pumped hydro as the most widely used source of energy storage.
Here’s how it works: take inexpensive or excess renewable energy, run it through an electrolyzer to create hydrogen, store that hydrogen for as long as needed using the fuel cells to convert the hydrogen back into electricity.
The University of California at Irvine established a test campus in 2016 that successfully produced renewable hydrogen from solar power using an electrolyzer. The hydrogen was then delivered to a natural gas combined cycle power plant to produce partially decarbonized electricity. This test facility proved we can upgrade our existing natural gas system into a renewable hydrogen system and utilize it to store renewable energy for months or even years.
“If you need to store terawatt-hours of energy — which is what the grid will need if it’s 100% renewable — it’s going to be way cheaper to store it in the form of hydrogen,” says Jack Brouwer, a professor of mechanical and aerospace engineering at the University of California, Irvine, who organized the project.
Long term storage especially makes sense in states such as California. As we recently noted, California receives much of its electricity from solar power during the day. Its solar arrays generate such vast amounts of energy that California’s grid operator often pays neighboring states, like Arizona, to take the excess electricity to ensure grid stability. Hydrogen storage could solve this “too much of a good thing” problem and has the added benefit of staving off future rolling blackouts that plagued the state in August.
Renewable hydrogen also makes sense for natural gas utilities on the chopping block up and down the West Coast.
“In California, for example, they want to get to zero carbon emissions,” explains Joe Ferrari, regional sales manager at MAN Energy Solutions. “So if you’re a natural gas utility, you are either facing the prospect of having your business become illegal, because you can’t sell fossil gas anymore… or you can transition to some type of renewable gas,” like hydrogen or synthetic methane.
Some utility companies are already investing in green hydrogen storage. Back in July, renewable energy company NextEra announced plans to build its first hydrogen production facility in Florida. Powered by solar energy, the hydrogen produced will replace some of the natural gas used at Florida Power and Light’s Okeechobee power plant. NextEra expects green hydrogen as a long-term solution for renewable energy storage in the decades to come.
As renewable energy becomes a larger and larger slice of our electric generation pie, reliable electricity storage solutions will become paramount. New technologies like renewable hydrogen and existing ones like batteries and pumped hydro will be needed to keep our lights on and our future bright.