WASHINGTON – As Colorado pushes toward its goal of 100% reliance on renewable energy by 2040, deploying grid-scale energy storage should play a crucial role, experts say.
Energy storage experts and utility company executives urged the U.S. Senate Energy and Natural Resources Committee last month to invest in making energy storage more affordable and in developing innovative storage technology.
“Energy storage really is the way we’re going to harness the full potential of alternative energy,” said Sen. Cory Gardner, R-Colo., who is a member of the Senate energy committee and sponsor of two storage bills this year.
Xcel Energy, Colorado’s largest utility, has committed to an 80% reduction of carbon emissions by 2030 and going carbon-free by 2050.
Xcel is relying more and more on wind and solar energy. But its lack of capacity to store renewable energy for times when the wind isn’t blowing and the sun isn’t shining hinders further reliance on clean energy, said Xcel CEO Ben Fowke.
“Wind and solar provide low-price clean energy to our customers, but they are intermittent and seasonal,” Fowke told the Senate energy committee at last month’s hearing on storage. “Grid-scale storage can help with renewable integration.”
For decades, Xcel and other utilities have used pumped-hydro storage systems, which involve two reservoirs at different elevations. When there is excess electricity, water is pumped from the lower reservoir to the upper one through a pipe. When energy is needed, water flows to the lower reservoir through a turbine, generating energy.
While pumped-hydro energy storage is still common, utilities are increasingly using lithium-ion batteries. These batteries, however, can only store power for up to four hours, which is hardly long enough to withstand a cloudy day, let alone a dreary winter.
“I think a lot of it is going to be on critical minerals, your rare earth minerals,” Gardner said. “But it’s also going to be innovation in different types of battery storage, not just lithium.”
Emerging storage technologyIn May, Gardner, Sen. Martin Heinrich, D-N.M., and five other senators introduced the Better Energy Storage Technology Act, which would dedicate $300 million to energy storage research. The bill aims to help develop technology for storing energy for months at a time to address the seasonal variation in wind and solar energy.
In 2012, the U.S. Department of Energy created a laboratory dedicated to energy storage research: The Joint Center for Energy Storage Research. Director of the center George Crabtree said energy storage technology is advancing rapidly but called for more investment from Congress, such as the BEST Act, to help transition to a modern electricity grid.
Chief among the center’s innovations so far is a long-duration flow battery based on water, sulfur and oxygen. Form Energy, a private sector startup, is attempting to commercialize the battery, which promises to fill a void in long-term, grid-scale energy storage.
Still, the flow battery is just one of the many technologies needed to meet the demands of a modern electricity grid and electric cars.
“Even if all four of our prototypes went to commercialization, this would not come close to satisfying the urgent need for a diversity of new battery materials for a diversity of emerging applications,” Crabtree said.
High cost of storageThe cost of storing energy with today’s technology is prohibitive, Fowke and Crabtree agreed.
Lithium-ion battery packs cost about $200 per kilowatt-hour, which is about twice the cost utilities are willing to pay, Crabtree said.
Tax incentives help offset the cost of investing in energy storage, but Fowke said many utilities don’t have the tax appetite to use the tax credits.
In April, Gardner and Heinrich proposed another bill, the Energy Storage Tax Incentive Act, which aims to give tax breaks to families who buy small battery systems for their homes and to utilities employing grid-scale energy storage.
Xcel, which is a contributor to Gardner’s campaigns, is working with bill sponsors to make sure families and businesses can take advantage of the proposed tax break.
‘There is no silver bullet’While Xcel is a “technology agnostic” company, Fowke predicted that new battery technology would not alone help Xcel meet its goal of 100% reliance on renewable energy by 2050.
“While the possibilities of storage technology are certainly promising, many people have misconceptions that batteries can address all future challenges of a clean energy grid,” Fowke said. “Like all things in energy, there is no silver bullet.”
Nuclear energy, carbon capture and renewable hydrogen energy would all play roles in reducing greenhouse gas emissions, Fowke said.
Crabtree also warned that new battery technologies could not alone eliminate greenhouse gas emissions from the grid.
“One of the most important things is we charge storage that we put on the grid with clean electricity,” Crabtree said. “Either through policy or incentives at the state level and at the federal level, to encourage that simple activity, is the most important thing that we can do.”
James Marshall is a student at American University in Washington, D.C., and an intern for The Journal.