With duck curves on the prowl and curtailment on the rise, there are dangers stalking utility-scale solar's natural habitat.
Solar developer 8minutenergy wants to ward off these threats with large-scale energy storage. The company spent the past year quietly picking up staff with years of experience developing storage at California utilities, and recently revealed the new practice with a pipeline of 1 gigawatt already in place. That quantity, though not yet finalized, dwarfs the 221 megawatts deployed across the U.S. last year.
8minutenergy worked its way up to 10th place on GTM Research's list of U.S. utility-scale solar developers. Now the team wants to incorporate storage into its expertise with wrangling land rights, interconnection and utility off-takers. Initial geographical targets include California, the Southwest, ERCOT and the Southeast.
“It's really kind of an ideal storm with much lower prices so these systems are much more cost effective,” said Steve McKenery, vice president of storage solutions. “We can do a solar-plus-storage project now at less than the cost of a new combustion gas turbine. That was not the case a few years ago.”
The company likes to focus on solar projects with 100 megawatts or more, to capture economies of scale. Going forward, a typical 100 megawatt PV project might come with 100 megawatts / 400 megawatt-hours of storage.
In fact, for the last year or so, all 8minutenergy developments have been designed to incorporate storage if desired; having land rights and interconnection already taken care of can speed up the storage deployment process.
The primary market will be pairing storage alongside new solar projects. This captures the ITC for the storage, and makes the solar generation dispatchable. That serves the offtaker by guaranteeing clean power for several hours of peak demand, but it also serves to future-proof 8minutenergy's core product against increasing curtailment rates in California.
If the company can deliver on that gas turbine-beating promise, it could open up lucrative capacity market revenue. There's also value to offer utilities in offsetting gas consumption for spinning reserves, said Carl Stills, vice president for storage integration.
In a previous job working on storage at the Imperial Irrigation District, he saw how utilities spend thousands of dollars a day on gas to maintain spinning reserves. Storage can stay ready for instantaneous response without burning fuel.
Storage on a major solar farm also serves a utility by increasing utilization of transmission infrastructure.
“Utilities that build transmission lines out for solar areas really use the capacity for that eight hours a day,” Stills said. “If you want to expand that out to include storage, if the price is right, you now are able to load up that line and optimize your transmission capacity. The clustering effect is huge.”
The company is also competing for standalone storage contracts where it serves a particular customer need.
“We can utilize our land and interconnection status that we have on 8minutenergy-developed projects to have a place to build the storage project and interconnect it to the grid fairly quickly and at a competitive price,” McKenery said.
In the developer role, 8minutenergy will stay technology and vendor agnostic. The initial focus is on lithium-ion batteries from proven, bankable suppliers like LG Chem and Samsung SDI.
The company maintains its own internal test facility, though, to verify the marketing claims of alternative solutions, like flow batteries and flywheels.
“Lithium-ion is the technology for the next 3-5 years,” McKenery said. “Beyond that, who knows. I hope somebody is able to come up with better product for half the price.”
The storage team is examining ways to integrate batteries into the solar plan most efficiently. One idea is to employ DC to DC architecture, which would feed the solar output into the batteries before going through an inverter to reach the grid. This could potentially save on equipment costs and reduce roundtrip efficiency losses compared to an AC architecture.
The addition of energy storage expertise generates a new basis of competition among the small group of companies operating at the 100-megawatt PV scale, said Colin Smith, a utility-scale solar analyst at GTM Research.
“This is what the industry's now demanding. If you look from an evolutionary standpoint, this is the landscape putting new forces and pressure on companies to change,” he said. “It's become a forced differentiator in the industry.”