A commission that studied the potential for projects to store excess renewable power generated in Maine has recommended that the state set a short-term goal of reaching 100 megawatts of capacity by 2025 to send an important signal to investors and developers.

The non-binding target is modest compared with what states such as Massachusetts and New York are proposing, and it doesn’t commit any state money. Still, the proposal recognizes the “value and benefits that strategic investment in energy storage can provide to energy consumers and the electrical grid,” according to the commission’s final report.

The recommendations, contained in a 16-page report, will next go the legislative committee that handles energy and utility issues.

Energy storage projects represent an emerging trend that dovetails with Maine’s ambitious plans to cut greenhouse gas emissions by making a wholesale transition to renewable energy. They provide a potential power supply solution for when the sun doesn’t shine and the wind doesn’t blow.

The transmission lines connecting Maine’s far-flung renewable generators to the regional electric grid sometimes are too weak to carry all their power. When that happens, grid operators order generators to reduce output – or even stop running – to prevent overloading and jeopardizing reliable service. The practice is called curtailment.

Increased energy storage capacity in Maine would reduce curtailment and help squeeze more usable power out of existing sources of renewable energy generation.

The commission also recommended that the state create an incentive for energy storage projects that are paired with renewables such as solar and wind. That could happen by boosting the contract price for new projects shown to benefit ratepayers or the grid. It said the Governor’s Energy Office should develop and propose more robust energy storage targets as part of a future, in-depth energy storage study.

Current storage mostly takes the form of strategically placed lithium-ion batteries. The huge, shipping-container-sized units soak up and send out energy at just the right times, such as when there’s excess power being generated by a wind farm, or when there’s a surge in demand on the grid.

Maine needs to create storage if it wants to expand wind and solar farms, because the electricity they generate is a use-it-or-lose-it thing. But unlike other states, Maine has no policies or incentives to entice developers to invest in the mega-battery units. That’s why the 14-member study commission was formed to gather information last fall.

“I was excited to be appointed to lead this commission, and I truly feel the report we produced will help guide Maine in our goal toward energy independence,” said Sen. Eloise Vitelli, D-Arrowsic. “The commission found that energy storage is an incredible emerging industry that will complement and help expand Maine’s already growing green energy industry.”

In addition, the group suggested that Maine address rate issues related to the cost of electricity at different times of the day. Wholesale power is priced higher when demand is greatest, such as on a hot summer evening. Solar farms can generate power during the day for storage, and it can be used when people come home and switch on their air conditioners.

Developers are considering several new solar farms in Maine, and a trade group that represents some of them applauded the commission’s recommendations.

“Given the upcoming contracting opportunities for large and small scale distributed generation, the ability to pair those bids with energy storage proposals for the first time will help our state to more efficiently and reliably integrate renewables into our energy mix,” said Jeremy Payne, executive director of the Maine Renewable Energy Association.

Reflecting that theme, the report warns that if the state fails to take the recommended “small steps” to promote energy storage, Maine ratepayers will suffer the costs.

“As the other states in New England increasingly invest in energy storage and reduce peak demand, Maine will be left carrying more peak load, resulting in more costs shifted to Maine ratepayers,” the report said.