Last month, independent power producer MN8 Energy announced it would combine 86 megawatts of utility-scale solar in West Virginia with two kinds of batteries: 280 megawatt-hours of lithium-ion storage, and 100 MWh of zinc-based batteries.
It’s not the first project to pair lithium-ion with more novel chemistries, but it’s one of the first in the U.S. aiming to demonstrate how it could work at commercial scale. Zinc batteries are an alternative chemistry that hasn’t yet been widely deployed on the grid; the systems that MN8 will rely on are manufactured by Eos Energy, and are designed to discharge for 10 hours. The project is expected to be online by 2030.
Google is the offtaker; the hyperscaler has committed to a 15-year term for all three technologies, starting when each comes online, a spokesperson said.
Will Broad, global director of policy and markets at the Long Duration Energy Storage Council, told Latitude Media he expects to see more projects combining different storage technologies in the coming years, as systems evolve and require flexibility “across different timescales.”
“Lithium-ion and long-duration storage are complementary; they can solve different problems, and there’s a strong case for using them together,” Broad said in an email.
Michelle Buczkowski, chief commercial officer at Eos, explained that for the MN8 West Virginia project, the idea is to use Eos’ zinc batteries to extend the availability of solar power beyond lithium-ion batteries’ usual four-hour duration: extending it the key evening hours of high electricity use, to well into the nighttime, as well as longer events that lithium-ion can’t handle.
Lithium-ion batteries are better suited to responding quickly to changing grid conditions than long-duration technologies, smoothing out sudden peaks and swings. But zinc comes with better fire safety, as well as longevity and domestic supply-chain advantages, which for Google “make it worth the added complexity,” the spokesperson said.
“Combining them can allow developers to optimize across these characteristics, rather than relying on a single technology to meet every requirement,” Broad said.
A good fit for data centers
The MN8 West Virginia project will support the local grid, which serves a data center Google has planned in West Virginia. Google also said the project has the “added benefit” of supporting its bring-your-own-capacity requirements in PJM. (That said, the specifics of those requirements are still in flux, after federal regulators rejected the grid operator’s proposed BYOC rules earlier this month.)
But pairing lithium-ion and long-duration storage could also be well-suited for on-site power for data centers. Their power use can swing sharply, requiring lithium-ion’s fast response, but they also want reliable, long-duration storage to back up the behind-the-meter power systems they are increasingly relying on to avoid long interconnection queues.
Thermal storage companies such as Antora and Tempo are also pitching themselves to data centers, with Antora co-founder and chief operating officer Justin Briggs noting that Antora’s long-duration batteries are “really complementary to lithium-ion batteries, which can deliver a few hours of power and provide a really excellent service to the grid.”
These alternative long-duration chemistries for years have struggled to get market traction. Three years ago, Julia Souder, CEO of the LDES Council, told Latitude Media that one of their biggest barriers to commercialization was that U.S. electricity markets and regulatory structures did not have a way to compensate LDES appropriately, stunting deployment.
But as Google’s role in the MN8 project demonstrates, demand from large energy users and hyperscalers is starting to change that. “Data centres and other large electricity customers increasingly need a combination of low-carbon electricity, predictable costs and dependable capacity,” Broad said. “A combination of storage technologies can help deliver that.”
The underlying problem hasn’t gone away, and the biggest barriers to LDES deployment are still commercial, rather than technical, according to Broad. But big buyers like Google represent a potential way around them.
“What’s interesting about projects such as [this one] is that large electricity customers can help overcome this challenge by entering into long-term agreements for the clean, reliable electricity they need, rather than relying solely on revenues from electricity markets,” he said.
