‘A battery in every basement’: How the lowly water heater could power the smart grid
A new coalition of co-ops, greens and DR boosters seeks to harness the power of a different sort of storage
ring the 1928 Presidential campaign, an ad for Herbert Hoover in the New York Times promised “a chicken in every pot, and a car in every garage.”
Gary Connett, director of member services at Great River Energy, has his own version: “A battery in every basement, and gas in every garage.”
He’s talking about water heaters and electric vehicle charging stations, two appliances which can be harnessed by utilities to shift demand and store energy. And while electric vehicles remain a nascent technology, water heaters are ubiquitous. There are roughly 50 million electric water heaters in the country, and according to new research from Brattle Group, they make up an enormous potential energy resource that could save consumers up to $200 annually while allowing utilities better control over their load curves.
The Brattle report was completed on behalf of three groups – the National Rural Electric Cooperative Association, Peak Load Management Alliance and Natural Resources Defense Council – and serves to kickstart a discussion on community storage initiatives the groups hope might operate similarly to popular community solar programs now under development. The report is titled “The Hidden Battery: Opportunities in Electric Water Heating.”
“There’s been talk of smart appliances for years, but somehow the water heater in the basement has been forgotten,” Connett said. “But I would argue it may be the most important, most strategic appliance, because it’s the only appliance today that has the ability to store energy.”
Great River is a transmission and generation cooperative providing wholesale electric service to 28 Minnesota distribution cooperatives, and Connett said the utility has more than 1 GWh of energy storage in 110,000 electric water heaters currently under its control – each one storing 12 Kwh to 14 Kwh of energy.
The utility also controls about 167,000 air conditioners. “I don’t know another utility that can say that,” Connett said. “Nearly a third of all air conditioners that great river serves are under our control.”
“Being largely residential, we want to take charge of our load curve,” he said. “And in order to do that, we have to do it one house at a time.”
Community storage
It seems new community solar projects are cropping up each week, and some see the potential for similarly-modeled storage programs – essentially the aggregation of fleets of residential appliances with energy storage capabilities. The NRECA-NRDC-PLMA work group is calling itself the National Community Storage Initiative, and hopes to focus attention on opportunities to develop national, regional and local markets for electric storage technologies.
“The community storage initiative is an effort to harness the untapped storage capacity of common electrical appliances and products that are dispersed in communities throughout the country,” said Keith Dennis, NRECA’s senior principal for end-use solutions and standards. Water heaters, he said, are common devices that can assist with peak shaving, thermal storage and provide ancillary services.
“We expect to have a diverse group of interests, and we are expecting innovation,” he said. Other technologies which could work in aggregated, residential storage fleets include ceramic block heaters and community swimming pools.
Great River actually has about 15,500 ceramic block heaters on its system, and they could be used in the same manner. But “the beauty of water heating is it’s a 12-month load. and it’s a load everyone is going to have,” Connett said, explaining the utility’s focus. “While we think electric thermal storage space heating is equally important, there are opportunities that water heating provides that go well beyond the heating season.”
