Plus Power plans to start work this spring on Maine’s largest battery storage project at the Gorham Industrial Park. Cross Town Energy Storage will be rated at 175 megawatts and provide the region’s grid operators with instant power when needed. Image courtesy of Plus Power

Construction is set to begin this spring in Gorham on one of New England’s largest battery storage projects, a preview of similar ventures that are seen as a missing link for optimizing the region’s growing fleet of solar and wind power plants.

Big batteries are considered essential to realizing Maine’s climate goals. That’s because the transition from fossil fuels to renewable power leans heavily on solar and wind – notably from proposed floating offshore wind farms – to help energize an electrified economy.

The problem is, solar and wind are intermittent sources of power. When the sun doesn’t shine and the wind doesn’t blow, other sources are needed to make up shortfalls and to balance supply and demand.

Today, those holes are largely filled by ramping up natural gas-fired plants. To replace them, the region will need a robust network of electric sponges to soak up renewable energy when it’s available, then discharge it when and where it’s needed.

Starting in mid-2025, the regional grid operator will be able to dispatch up to 175 megawatts of capacity from the Cross Town Energy Storage facility. The $100 million-plus project will feature 156 tractor-trailer-like containers spread across five acres in the Gorham Industrial Park, stuffed with lithium iron phosphate batteries. It’s being built by Houston-based Plus Power LLC, which has 60 energy storage projects online or in development across the U.S. and Canada.

Cross Town is part of a national trend to build giant battery plants. Growth is reflected regionally by a revealing statistic: Roughly 44% of developer requests to connect to the ISO-New England high-voltage grid now involve batteries, up from 10% just three years ago.

The activity is driven in part by rule changes that went into effect in 2018, which allow battery projects to compete with conventional power plants in the wholesale electricity markets.

More than 1,000 megawatts of new battery capacity have been approved to supply electricity in the next few years in New England. Some batteries are next to solar farms. Others are stand-alone projects, like Cross Town.

Maine has six smaller battery projects up and running, but they’re a fraction the size of Cross Town. That’s why Cross Town may be a model for what large-scale battery storage will look like in the state. And while battery storage has been less controversial than some other energy proposals, three fires in New York state have led to a review of safety practices in the fast-growing industry.

Cross Town will be able to perform several key services, which is why some in the industry call giant batteries the “Swiss army knife” of the electric grid.

One task is to relieve congestion on southern Maine’s constrained electric grid by absorbing and storing excess energy, as more solar and wind comes online. Cross Town is next to a Central Maine Power substation, giving the batteries a direct connection to high-voltage lines from the north.

Typically, electricity has to be used the instant it’s generated. One obstacle to integrating large solar and wind projects is that grid operators must constantly account for cloudy periods or sudden drops or surges in wind speed. Absorbing and storing excess power from wind and solar can capture energy that might otherwise be wasted on a very sunny or windy day.

Batteries can be deployed in milliseconds. That makes Cross Town valuable for providing what grid operators call ancillary services, such as maintaining the system’s proper frequency standard to keep motors and other electric equipment operating properly. That standard is measured in cycles per second, or hertz.

“It’s like a pacemaker for the grid,” said Mark Tourangeau, Plus Power’s chief revenue officer. “It keeps the frequency at 60 hertz to maintain reliability.”

Tourangeau also noted that Cross Town and another Plus Power venture won seven-year contracts with ISO-New England during the 2021 annual bid process meant to line up future generating capacity at the lowest prices. The second project is in Carver, Mass.

These batteries can be charged from the grid in the middle of the night, when excess power is available and wholesale prices are low. During periods of peak demand, such as hot summer nights when air conditioners are struggling to keep buildings cool, the stored energy can be released back into the grid. Plus Power makes money by selling during these peaks, when wholesale prices are high. Buy low, sell high. This strategy is called energy arbitrage.

THE VALUE OF BATTERIES

Battery projects have key ratings, including the instantaneous power they can release and the duration they can do it. At 175 megawatts of power capacity, Cross Town will be able light 175,000 average homes. It’s also rated at 350 megawatt hours, which means it could discharge that much energy running full tilt for two hours.

Two hours might not sound like much time, but because battery plants can turn on and off in an instant, they can be a valuable tool for grid operators.

“Our job is to make sure supply and demand stay in balance on the grid at all times, and (the batteries) can do a lot,” said Anne George, a vice president and chief of external affairs and communications for ISO-New England.

In winter, George noted, batteries will play an increasingly important role around dinner time, after solar farms have faded out but demand is ramping up as people return home from school and work. It’s notable that next to wind farm proposals, battery storage is what developers are pitching to meet the region’s near-future capacity needs.

“Batteries and wind, that’s pretty much what’s in our queue,” George said.

At the same time, developers are working on longer-duration battery systems that can discharge at full capacity for several hours. And the size of the projects also is growing. ISO-New England has a proposal in Massachusetts rated at over 700 megawatts.

Maine currently has 63 megawatts of grid-connected energy storage at six locations. The largest is 20 megawatts, so Cross Town’s contribution will be a significant step toward a goal set by the Legislature in 2023 to develop at least 300 megawatts by 2025 and 400 by 2030.

Battery storage also got a boost during the last legislative session with passage of a bill that exempts systems with a capacity greater than 50 megawatts from sales and use taxes.

SAFETY PROTOCOLS DRAWING ATTENTION

Cross Town’s site has been cleared of trees and is being prepared for construction in late spring. Unlike many power plant and transmission line proposals that drew opposition in Maine, Cross Town acquired its permits without much attention. That may be because it’s located in an industrial park, away from homes and next to a substation.

It also may be because battery storage has had a low public profile. When the Gorham Planning Board held an initial meeting about the project in April 2022, only one person expressed concerns, asking about the safety of lithium batteries.

Ed Montalvo, the president of Montalvo Corp., has an office near the site. He wanted to know more about the safety issue and discussions with the town’s fire department.

They turned out to be very relevant questions. Recent fires at battery projects are raising public awareness and leading officials to take a closer look at safety protocols.

Three fires in 2023 in New York state led Gov. Kathy Hochul to create a working group to look into best practices and fire codes at battery installations. No one was hurt in the incidents, and the causes of the fires are still under investigation.

The outcome will interest Ken Fickett, Gorham’s fire chief. He has been working with Plus Power and must approve an emergency response plan before the project begins operation.

“We’ll make sure our firefighters know what we’re supposed to do, and not supposed to do,” Fickett said.

Fickett said he didn’t think Maine needed to establish the sort of task force New York created, but added he is still learning about the issue and his opinion could change.

Plus Power is using battery systems supplied by Sungrow, a Chinese global clean energy company. There will be 3,072 battery cells in each 30-foot long container. The containers have safety features that include heating and cooling equipment, thermal sensors, fire detection and suppression, and 24/7 monitoring.

The company works with former firefighters as consultants, according to Polly Shaw, the company’s chief external affairs officer.

“Safety always comes up, and we address safety vigorously,” Shaw said. “We want to be a model for the development of battery storage.”

This story was originally published by The Maine Monitor, a nonprofit and nonpartisan news organization. To get regular coverage from the Monitor, sign up for a free Monitor newsletter here.