Maine Adding 175 MW/350 MWh Of Battery Storage To Its Electrical Grid

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The state of Maine recently has been actively promoting clean energy programs such as battery storage projects to lower the state’s greenhouse gas emissions. A few years ago it set a goal of installing 100,000 heat pumps in the state by 2025. With an assist from educational programs and certification courses for installers, together with economic incentives from the state government, Maine got there 2 years early and is now pursuing a new target of another 175,000 heat pumps by 2027. Getting people to switch to heat pumps took a lot of effort and educational outreach to residents to offset the negative publicity sponsored by the fossil fuel industry.

Maine is also aggressively pursuing offshore wind power. Because the waters off the coast of Maine are so deep, using turbines mounted directly to the ocean floor is not feasible and so the state is a pioneer in floating wind technology in the Gulf of Maine. To help electrify the state’s economy, community colleges in Maine will soon be creating new training programs for workers in the offshore wind industry.

Renewables Need Battery Storage

An influx of renewable energy needs the ability to store some of it for later use. That allows grid operators to treat renewable electricity as “dispatchable,” meaning that when the grid needs it, it will be available. Otherwise, methane powered peaker plants are needed to meet the need during periods of high demand.

Houston-based Plus Power has plans to begin construction this spring of the Cross Town 175 MW/350 MWh battery storage installation at the Gorham Industrial Park in the town of Gorham. When completed by mid-2025, it will be one of the largest energy storage facilities in New England. The $100 million-plus project will feature 156 containers spread across five acres in the Gorham Industrial Park with lithium iron phosphate batteries inside. Plus Power is actively involved in the construction of 60 energy storage projects either already operating or in development across the US and Canada.

According to the Maine Monitor, the Cross Town facility is part of a national trend to build large battery plants to store renewable electricity when it is plentiful and send it back to the grid when demand requires. Growth is reflected regionally by a revealing statistic — about 44% of developer requests to connect to the ISO-New England high voltage grid now involve batteries. That’s 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 MW of new battery capacity has been approved to supply electricity in the next few years in New England. Some are adjacent to solar farms, others are stand-alone projects like Cross Town.

Maine has six smaller battery projects up and running, but they are a fraction of the size of Cross Town, which may become a model for what large scale battery storage will look like in the state. 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.

Why Battery Storage

One use for battery storage 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, which 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. “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. In addition to being charged with renewable energy, 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 is a strategy often called energy arbitrage.

Batteries And Grid Services

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

Two hours might not sound like much time, but because battery storage systems 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.

George noted the batteries will play an increasingly important role in the winter 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 is growing. ISO-New England has a proposal in Massachusetts rated at over 700 megawatts.

400 MW By 2030

In 2023, the Maine Legislature set a goal to develop at least 300 MW of battery storage by 2025 and 400 MW by 2030. Battery storage also got a boost during the last legislative session with the passage of a bill that exempts systems with a capacity greater than 50 megawatts from sales and use taxes.

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. Three fires in 2023 in New York state led Governor 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. It should be noted that lithium iron batteries have a much lower fire risk than conventional lithium ion batteries. Some companies are turning to sodium ion batteries in storage systems partly because their risk of fire is much lower.

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 Takeaway

It is good to hear of battery storage projects coming to places other than California and Texas. The only question around the CleanTechnica raw bar today involves batteries for China. Some are welcome, apparently, if they are used in battery storage facilities. Others are not if they are used to power electric cars. We aren’t saying the rule should be one way or the other. We just don’t understand why some batteries are blessed and some are not. Perhaps our poor brains are simply not able to comprehend the complexities of international trade issues.

Hat Tip to Dan Allard.