Todd Woody, BLOOMBERG,COM
California wants to replace millions of gas water heaters with high-tech electric ones to serve as “thermal batteries” for storing solar and wind energy.
Nearly every home has a water heater, but people tend not to think about it until the shock of a cold shower signals its failure. To regulators, though, the ubiquitous household appliance is increasingly top of mind for the role it could play in reducing greenhouse gas emissions and weaning the power grid from fossil fuels
High-tech electric water heaters can double as thermal batteries, storing excess production from wind and solar generators. In California, officials aim to install them in place of millions of gas water heaters throughout the state.
That would reduce the need to fire up polluting fossil fuel power plants to supply electricity for water heating after the sun sets.
“Water heaters have significant potential,” says Commissioner Clifford Rechtschaffen of the California Public Utilities Commission. “We know we’ll need a tremendous amount of storage to get to our decarbonization goals. We’re challenged now in evenings when renewable energy production declines and demand peaks.”
The focus is on heat pump water heaters, which transfer warmth from the atmosphere to a tank. They’re up to four times as efficient as conventional gas or electric water heaters. Nationwide, about half of water heaters are powered by natural gas. In California, water heating is one of the biggest consumers of fossil fuels and gas water heaters account for 90% of the market. Swapping them for heat pump versions could reduce greenhouse gas emissions from water heating in the state by as much as 77%, according to a paper published in January by the nonprofit New Buildings Institute.