The nation’s 50 million residential electric water heaters collectively represent a significant – and vastly underutilized – energy storage resource capable of leveraging substantial environmental and cost benefits according to new research commissioned by the National Rural Electric Cooperative Association (NRECA), Great River Energy, the Natural Resources Defense Council (NRDC), and the Peak Load Management Alliance (PLMA).
This finding from the global economic consulting firm The Brattle Group was recently announced at the launch of an initiative designed to promote growth in community-based approach to energy storage, dubbed “community storage.” By aggregating distributed energy technologies and home appliances, electric cooperatives are developing community storage to increase energy efficiency, better integrate renewable energy resources onto the grid, and reduce customers’ monthly electric bill.
One such community storage program managed by Great River Energy has been able to store a gigawatt of energy each night by controlling the electric resistance water heaters of 65,000 end-use members.
“At Great River Energy, we believe there’s a battery hidden in basements all across our service territory,” said Gary Connett, director of member services at Great River Energy. “When the wind is blowing or the sun is shining, large capacity water heaters can be enabled to make immediate use of that energy to heat water to high temperatures. The water heaters can be shut down when renewables are scarce and wholesale costs are high.”
Even in regions heavily reliant on coal and natural gas to generate electricity, the Brattle research shows that consumers have options for saving money on their electric bills and reducing carbon dioxide (CO2) emissions associated with their water heating. Consumers can reduce CO2 emissions by up to 30 percent using their water heater as a thermal battery. Consumers can reduce their CO2 emissions by more than 50 percent using heat pump water heaters.
These same consumers will be enabling integration of clean, renewable resources. Further, the emission reductions of community storage will compound as more consumers participate and the electricity sector transitions to cleaner fuels and generation technologies.
“Co-ops have been controlling large water heaters for decades in order to reduce demand at peak times, which also reduces members’ electric bills. A community storage program using advanced water heaters allows us to do even more: we can store energy, we can optimize the power grid by shaping demand and we can integrate more renewable resources,” said Keith Dennis, NRECA’s senior principal for end-use solutions and standards.
“Smart, grid-connected electric water heaters represent a promising possibility for a more efficient, more economic, and ultimately lower-emissions electricity system,” said Robin Roy, director of building energy efficiency and clean energy strategy at the NRDC. “Given that water heating represents more than 15 percent of household energy use, this is a great opportunity to cut energy waste and also the emissions from electricity generation.”
“The National Community Storage Initiative will focus attention on the immediate opportunity for national, regional and local market development efforts to demonstrate the potential of ‘behind-the-meter’ electric storage technologies,” said Rich Philip, manager of products and services at Duke Energy, and PLMA chairman.
The Brattle Group conducted the research on behalf of the four sponsoring organizations.