A recent study shows that the humble water heater has the potential to save its owners, and the environment, significant energy and money. With two new technological upgrades, smart and heat pump water heaters, homeowners can expect to reduce greenhouse gas emissions 30-50 percent.
“Smart” water heaters are hooked up to the electrical grid and have the capability to turn on the heater when the draw on the grid is lowest, saving costs by using electricity during non-peak hours. They also can be programmed to turn on when renewable power resources are more available, again reducing the draw on the grid.
Heat pump water heaters are able to draw warmth from the air surrounding them and use this warmth to preheat the water before it passes through the element, saving energy by reducing the amount of heat needed.
The global economic consulting firm The Brattle Group recently released findings that show using these technologies could save significant energy and reduce the amount of greenhouse gas emissions put out by local power generation. The study was commissioned by National Rural Electric Cooperative Association (NRECA), the Natural Resources Defense Council (NRDC), the Peak Load Management Alliance (PLMA) and Great River Energy (GRE).
The study showed that consumers can reduce CO2 emissions by up to 30 percent using their water heater as a thermal battery and by more than 50 percent using heat pump water heaters.
Results were featured at an event earlier this month introducing the concept of “community storage,” where whole neighborhoods are outfitted with this new technology, thus saving electric utilities money and reducing pollution from coal-based electrical generation.
“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.”
More findings from the study include:
- Reducing water heating load during higher cost peak times–either through an overall reduction in energy consumption by more efficient heat pump water heaters or load shifting through grid-connected electric resistance water heaters–can reduce energy costs across the system and help defer the need for expensive new power plants. Both types of water heaters can reduce the use of older, costlier and often dirtier electricity generating units.
- Heat pump water heaters provide “the most consistent environmental benefit” on a per-water heater basis through overall reductions in energy consumption, generally reducing carbon emissions resulting from water heating by about 50 percent.
- Electric resistance water heaters can also offer environmental benefits, although they are more nuanced; cuts in carbon pollution depend on the fuel mix used to generate electricity and the water-heating control strategy. Still, grid-connected electric resistance water heaters offer the potential to reduce carbon pollution by up to 30 percent, partly because they give utilities greater flexibility to use lower polluting fuels or clean energy such as solar and wind power.
- Both heat pump water heaters and grid-connected electric resistance water heaters can have very strong positive economics, depending on market conditions. Controlled electric resistance water heaters provide the largest economic benefit on a per-water heater basis under the electricity market scenarios examined in the study.