Water Heater Ban Threatens Demand Response Efforts

The U.S. Department of Energy (DOE) recently banned a piece of equipment that is a vital component in one of Great River Energy and Arrowhead Electric Cooperative’s most successful demand response programs.

For more than 25 years, electric cooperatives have promoted electric thermal storage (ETS) water heating programs. These programs incorporate large capacity electric resistance water heaters that are “charged” in the night time hours using low-cost, off-peak electricity to heat enough water for the following day’s use.

Great River Energy’s member owners have been among the most successful cooperatives in the nation at incorporating ETS water heating among their membership. Nationwide, more than 100 electric cooperatives have installed more than 150,000 ETS water heaters in 20 states, which reduces daily peak electricity usage by an estimated 500 megawatts.

According to the new DOE standard, electric water heaters with a rated storage capacity greater than 55 gallons must have an efficiency factor of 200 percent. To meet this new standard, electric water heaters greater than 55 gallons will have to be heat pump water heaters. While this new standard should deliver significant energy savings nationwide, it will effectively terminate ETS water heating programs, overlooking some of the latent benefits of ETS water heating.

For example, ETS water heaters essentially act as “batteries” that store renewable energy. Electricity demand plummets in the overnight hours, which is when wind turbines – a common renewable energy source in the Midwest – generate the most power. Because electricity must be consumed at the precise moment it’s generated, ETS water heaters provide a means of storing that electricity and compensating for the volatility of wind generation.

“In Minnesota, a large portion of the energy charging these off-peak water heaters will be wind,” said Great River Energy Director of Member Services and Demand Side Management Gary Connett. “This program allows our members to absorb some of the renewable energy that’s generated in the overnight hours.”

Members of Great River Energy member cooperatives benefit whether or not they’re enrolled in ETS water heating. Participants save money by heating their water with low-cost, off-peak electricity. Non-participants benefit because their cooperative is able to use electricity more economically in the overnight hours.

Great River Energy, on behalf of its member owners, has mobilized state and national organizations in a campaign to request and exemption from the ban and allow electric resistance water heaters over 55 gallons in sized to be allowed if they are part of a utility-sponsored ETS program.

Great River News ~ July

2 Responses to “Water Heater Ban Threatens Demand Response Efforts”

  1. David Ferguson says:

    “According to the new DOE standard, electric water heaters with a rated storage capacity greater than 55 gallons must have an efficiency factor of 200 percent.”

    How can any system have an efficiency of 200%? It sounds like a violation of the laws of thermodynamics.

    • arrowelec says:

      It does sound odd that something can have an efficiency of greater than 100%. Heating and cooling systems for both space and domestic water in today’s world can gain efficiency’s greater than 100% via the use of heat pumps. Specifically, the new DOE standard is looking for consumers to begin using heat pump water heaters. Heat pump water heaters have a small air source heat pump mounted on the top of the water heater that functions similar to that of an air source heat pump commonly installed in new homes today.

      One concern about the use of these units in colder climates however, is that the heat pump water heater will typically be located in a space conditioned area of your home. In the winter months while your space heating system is hard at work, the heat pump water heater will be using this conditioned air to gain efficiency’s to heat your domestic hot water. One theory is that in doing so, we may possibly be making our space heating systems work harder to compensate for the heat pump water heater. The theory has not been tested.

      Organizations such as Great River Energy and others are evaluating the use of heat pump water heaters to ensure the recommendations we make to our members in the future are the most economical.

      This DOE ruling and our use of the article in the blog and newsletter has alarmed numerous members. It is important to note that those using larger water heaters on our off-peak program will not lose this functionality. However, what we may find if an exemption is not granted is that as water heaters need replacement an 80 gallon or larger model may not be available for purchase. It is at that time members may lose the ability to participate in our off-peak water heating program.

      We encourage you to contact your federally elected officials to facilitate an exemption and to help us relay the importance of this issue.