Sure, small-scale batteries in homes and businesses can link up and deliver veritable megawatts of capacity. But there’s nothing like the sheer adrenaline rush of stacks and stacks of lithium-ion cells packed into climate-controlled boxes and blasting electrons faster than a coal plant operator can say “secular decline.”

So who’s got the biggest battery?

Elon Musk supplied the biggest lithium-ion battery to a wind farm in South Australia back in 2017, and that project retains the biggest-battery title two years later. But the early-adopter phase is about to end: Contracts for bigger and bigger batteries will jockey for dominance into the early 2020s. Interconnection queues suggest even bigger ones will follow, north of 500 megawatts.

This size trend reflects the increasing ambitions of storage developers to serve not just a little frequency regulation but real bulk capacity. Some projects on this list explicitly set out to take over for gas plants; others are designed to make use of an overabundance of solar energy, turning it into peak power and thereby obviating the need for more gas burn.

That still leaves work to do to unlock a highly renewable grid. Even the biggest batteries on the books don't have durations long enough to fully replace fossil-fueled capacity. But there’s enough value on the table now to make these projects pencil out, and the premium for instantaneous, flexible capacity is only going to grow.

To make sense of this battery arms race, GTM plumbed our recent coverage to bring all the massive contenders together in one place. Here’s what you need to know about the “100-megawatt club,” at least until another announcement comes along and scrambles the lineup.

(A note on terminology: The list focuses on lithium-ion battery plants, built or contracted, that have been confirmed to GTM. They are ranked on megawatt capacity, though in the case of ties, projects with higher megawatt-hour capacities and earlier online dates are listed first.) 

8. Neoen Hornsdale: 100 MW/129 MWh

  • Online date: November 2017

If there’s a golden rule of utility procurement, it’s that record-busting infrastructure investments are best designed, approved and executed in extremely short periods of time. Tesla CEO Elon Musk was really just going by the book when he promised South Australia he could supply a 100-megawatt battery in 100 days or it would be free.

Somehow, nobody has copied that playbook since, and this facility remains the only mega-battery on this list that has actually been built.

7. Strata Oxnard: 100 MW/400 MWh

  • Online date: December 2020

The people of Oxnard, a coastal California town, objected to a new gas plant taking up prime beachfront property for the foreseeable future. NRG's Puente plant got the boot, and Southern California instead chose a 195-megawatt suite of batteries, anchored by this one from storage newcomer Strata Solar, a North Carolina-based solar developer. 

6. AES Alamitos: 100 MW/400 MWh

  • Online date: 2021

Independent power producer AES figured out how to plan massive batteries even without going viral on Twitter. This project, contracted with Southern California Edison back in 2014, will help replace a cohort of coastal gas plants shutting down in Southern California. Renewables are on the rise, and the metro L.A. load pocket needs good clean capacity.

This one could have a brief stint as the world’s largest battery, unless PG&E’s Moss Landing projects make it to market on time despite bankruptcy-induced uncertainty.

5. AES Arizona: 100 MW/400 MWh

  • Online date: 2021

Utility Arizona Public Service needs more power in the evenings, and it has a lot of cheap solar to work with. In addition to installing batteries at existing solar plants, APS tapped AES to build a beefy standalone battery, the largest individual system among the 850 megawatts announced this spring.

APS learned how to deal with storage in partnership with AES’ storage division, now Fluence. The relationship hit a snag when an explosion rocked one of those battery plants (the official cause is still undetermined), but APS subsequently affirmed its interest in further battery development.

4. Tesla Moss Landing: 182.5 MW/730 MWh

  • Online date: December 2020

Time for Tesla to build big on its home turf. The system will sit on PG&E land in the existing Moss Landing substation, along California's Central Coast, keeping development costs low. The prime directive is maintaining local capacity, but Tesla can also bid into grid operator CAISO's markets for energy, ancillary services and more. A self-respecting storage plant would never settle for just one revenue stream.

3. NextEra Skeleton Creek: 200 MW/800 MWh

  • Online date: 2023

This battery will connect not just to a major solar plant but a wind farm too, making it the largest triple hybrid power plant in the country, if nobody beats it to market. NextEra put this deal together for the Western Farmers Electric Cooperative, which needed to build new capacity. The numbers turned out more favorable for solar and storage compared to a gas peaker, and the cheap wind sweetened the deal.

2. Vistra Moss Landing: 300 MW/1,200 MWh

  • Online date: December 2020

Utility PG&E had the good sense to get this approved by regulators just months before entering into bankruptcy. The batteries will fill an old gas turbine hall owned by Vistra, in an attempt to reduce reliance on gas capacity in the South Bay region. It’s not clear if this project will shut down gas plants, per se, but it will make it harder for them to extract special payments from ratepayers out of a sense of urgent need.

1. FPL Manatee Energy Storage Center: 409 MW/900 MWh

  • Online date: late 2021

And here we are at the biggest of them all. Regulated utility Florida Power & Light recently discovered the high rates of solar irradiance in the Sunshine State and has since embarked on a wave of solar construction. This mega-battery will store some of that solar generation and release it on demand, taking over for two aging gas plants in the area.

Large battery development is new territory for the utility, but sister company NextEra Energy Resources has done much pioneering work in the renewables and storage industries. Too bad an impenetrable regulatory firewall separates the two companies, or there could be a lot of synergy there.