Supermarket frozen section
Credit: Phillip Pessar / Creative Commons

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National Grid is looking to recruit as many as 50 grocery stores in Rhode Island and Massachusetts to test an artificial intelligence software platform designed to lower their refrigeration energy use during peak demand periods, thereby reducing their costs and easing stress on the electrical grid.

“One of the overall goals of the program is to explore whether commercial refrigeration systems can feasibly participate in our demand response programs,” said Maxwell Halik, a product developer on National Grid’s growth and development team. “Historically, the loads tend to be more HVAC driven. This could help us expand the scope of the types of assets that can participate.”

The utility is partnering with the Rhode Island Office of Energy Resources and the Axiom Cloud software company on the pilot project. It is being funded by a grant of more than $900,000 from the U.S. Department of Energy. 

Companies that participate in National Grid’s demand response programs receive financial incentives to reduce their energy use during high peak demand periods in the summertime. Companies decide how often they wish to participate, but those who participate most actively can make $10,000 or more, Halik said. 

The concept is called load shifting. In this case, supermarkets will shift their high energy use to just before and after a peak demand event. 

“The idea is that when stores would be normally participating in a peak load event — a hot summer day when the energy supply of the grid might be driven more by fossil fuel generators — this platform would allow those stores to avoid consuming power,” Halik said. “They could shift that load because they’ve pre-cooled their freezers in advance.”

The technology developed by Axiom Cloud, called Virtual Battery, helps supermarkets participate in demand response and reduce their energy consumption automatically. The app can respond to utility notifications or forecast when a peak demand period is coming. Prior to the peak, it lowers the temperature in the freezer units — essentially storing more thermal energy in the frozen foods. 

The freezers are then set back to their original temperatures during peak periods — when energy is more expensive and the distribution system is more stressed — lowering the store’s power draw. 

“We are intelligently pre-cooling,” said Turner Anderson, a lead sales engineer for Axiom. “Once food products are frozen, as long as they stay at their set point or below, there is no impact to food quality or safety.”

The majority of stores have a controller in their mechanical room that gathers data in real time, he said. The Axiom app adds an additional level of artificial intelligence, making energy use on the frozen side of the refrigeration system more flexible.

The app also monitors performance and can predict equipment issues before a breakdown, he said. 

The app is already deployed in supermarkets in California. This program marks its debut in the Northeast. 

Halik said they estimate that the load shift potential from the average store is 20 to 50 kilowatts per peak demand event. So with roughly 2,000 grocery stores across its territory in the two states, the total load shift potential per event if all refrigeration loads were managed is 40 to 100 megawatts, he said.

Carrie Gill, administrator of grid modernization and system integration for the Office of Energy Resources, said they need a minimum of 25 stores to participate in the pilot, and are hoping to include a range of store sizes. 

“We are just starting our outreach,” Gill said. “We want to see that grocers are interested, and whether they are willing to continue to participate in the future.”

Participation in the program, scheduled to start in early 2022, is free for a year. After that, stores that want to continue using the app would have to pay a subscription fee. 

The program will generate more revenue for grocery stores, but demand response programs also have “a really excellent cascading set of benefits for all ratepayers,” Halik said. 

“First, adding more to our demand response programs means we can displace more fossil fuel peaker loads, which is an environmental benefit,” he said. “And second, adding these commercial customers reduces strain on our distribution networks, which helps lower the cost of upkeep.”

Lisa Prevost

Lisa Prevost is a longtime journalist based in Connecticut. She writes regularly about housing, development and business for the New York Times. Her work has also appeared in the Boston Globe, CNBC.com, Next City and many other publications. She is the author of "Snob Zones: Fear, Prejudice and Real Estate." A native New Englander, Lisa covers Connecticut and Rhode Island.