A handful of grocery stores in New York could produce ice over night as an unusual way of storing energy and working with the local utility.

The technology to make and manage the ice will be provided by a young startup backed by the chief technology officer of Tesla tsla , among other investors.

On Tuesday, startup Axiom Exergy announced that it won a deal to provide $5 million worth of its refrigerator batteries to grocery stores in Brooklyn and Queens. The grocery stores will be able to use incentives from utility Consolidated Edison to pay for the technology.

ConEd is looking to better manage the demand on the grid during peak times of day, like a hot summer afternoon when city residents turn on their air conditioners. The utility is looking to avoid building a $1.2 billion substation in the area by adopting a variety of new energy technologies.

By encouraging grocery stores to use energy to make ice at night, instead of during the middle of the afternoon, the utility can shift some of its peak load and the grocery stores can save money on their energy bills.

Axiom Exergy’s technology switches a supermarket’s refrigeration units over to use frozen salt water tanks to keep cool. When the refrigerators are being cooled by the ice tanks, they don’t need to use their own power-hungry cooling systems.

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The company’s software and data system continuously detects when grid rates fluctuate and manages the process. The ice batteries can also provide backup cooling if the power grid goes down, enabling supermarkets to keep perishable food cold during blackouts.

The idea of using heating and cooling to store energy isn’t new, but entrepreneurs are beginning to think of new ways to manage so-called “thermal energy” using new and cheap computing technologies like data algorithms, sensors, wireless networks, and cloud computing.

Changes for the power grid are pushing utilities in certain regions to try out new technology to better manage energy sources. For example, Southern California Edison is working with Alphabet’s Nest goog to try to convince 50,000 of the utility’s customers to agree to have Nest thermostats automatically reduce the amount of energy they use during peak grid times next summer.

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Earlier this summer, Axiom Exergy announced that it had raised $2.5 million from investors including Tesla’s CTO JB Straubel, the MIT Angels, Victory Capital, the Element 8 fund, Sierra Angels, and the Propel(x) investing network.