ORIGINAL REPORTING: How Hot Water Heating Can Be Energy Storage
Utilities in hot water: Realizing the benefits of grid-integrated water heaters; Water heaters offer storage capabilities at a fraction of the cost of batteries. The challenge is getting everyone a piece of the returns
Herman K. Trabish, June 20, 2017 (Utility Dive)
Editor’s note: More utilities are seeing hot water heating as a better deal than batteries.
A wave of interest is building in grid-integrated water heating (GIWH) as a path to system flexibility at a fraction of the cost of battery energy storage. At last count, 53.6 million of the 118.2 million U.S. water heaters were electric. Each could act as a battery for load shifting, peak shaving, or to integrate renewables, according to a Regulatory Assistance Project (RAP) paper. Hot water is used largely by residential utility customers in morning and evening hours. But it can be heated when power is available and then stored for use during the morning and evening without increasing system burden. And, to optimize the use of variable renewables, it could be heated at night to take advantage of high wind production and at midday to take advantage of abundant solar production.
Effective utility control of residential water heating could integrate up to 100,000 MW of additional variable U.S. wind and solar energy. Transforming the U.S. electric water heater fleet to 100% GIWH represents a $3.6 billion per year market, according to think tank Rocky Mountain Institute (RMI). And utilities, GIWH manufacturers, installers, solar companies, aggregators, and customers themselves can all share in the financial bonanza. Utilities across the country are catching on. There are GIWH pilots at Portland General Electric (PGE), Arizona Public Service (APS), and Green Mountain Power (GMP) in Vermont. PJM has introduced GIWH for frequency regulation and the California Energy Commission is discussing GIWH. A new wave of utility-led grid interactive water heating pilot programs is emerging... click here for more