Battery-powered appliances will be the future of home clean energy

August 12, 2024

Your appliances, you should know, will come loaded with batteries. We’ll probably have energy storage in our stoves and water heaters, perhaps even our washers and dryers.

Traditionally, batteries’ main purpose was to make gadgets portable. Today, they’re emerging as a shortcut on our path to “electrify everything.”

To switch from fossil fuels, we’ll need to plug in a bunch of new things: our cars, our stoves, our heaters and more. Many homes were not designed to carry this kind of load. Installing high-voltage wires, upgrading panels and rewiring your connection to utility poles is like building an electric highway into your home when all you have is a country road.

These retrofits are expensive — if you can find someone to do them, given the crush of new demand. Instead of rewiring our homes and upgrading grid infrastructure, appliances with batteries will allow us to stash energy around the house for when we need it, eliminating a final barrier to stop burning natural gas and heating oil inside our homes.

This is one of our best shots to decarbonize existing buildings. In the transportation and electricity sector, only a few hundred companies, automakers and utilities, must change their practices to phase out fossil fuels. But tamping down buildings’ emissions requires millions of individual households and property owners to make expensive, unfamiliar investments.

Little batteries are here to help.

Induction stoves

Induction stoves are the first major appliances to come with batteries. While a standard 120-volt plug can handle most daily cooking routines, running an electric oven and four burners draws a blistering 10 kilowatts, equivalent to more than 10 space heaters running full blast simultaneously. To handle that much juice, if only for a few minutes, you need a 240-volt outlet, like the ones for clothes dryers or conventional electric ovens.

Millions of homes do not have one, especially in the kitchen. In my own 1940s condominium, my electrician estimated running the wiring for a 240-volt outlet for an induction stove will cost $3,800. Battery-enabled stoves avoid this by plugging into an existing 120-volt outlet. When a burst of electricity is needed, the battery discharges energy. No new wiring necessary.

These little batteries are not quite here yet. For now, no major manufacturers are integrating batteries into their appliances. Rheem, a global water heater manufacturer, released the first 120-volt water heater heat pump last year, although it doesn’t include energy storage.

But start-ups are rushing into this space.

San Francisco-based Impulse Labs plans to sell its first battery-enabled induction stove in the next year or so. Its 3-kilowatt-hour battery packs enough electricity to roast a Thanksgiving turkey with all the fixings, or cook three meals during a blackout, says founder Sam D’Amico. Channing Street Copper will ship its full-range Charlie model later this year for $5,999 before incentives. Charlie offers the option to plug other appliances into the stove, like your refrigerator or phone, as backup power. Both appliances use batteries to supplement, rather than replace, electricity from the 120-volt outlet. The batteries’ lithium iron phosphate chemistry is more stable and environmentally friendly than traditional lithium-ion batteries in electric vehicles or phones.

Neither is aimed at the lower end of the market, even after generous rebates. But both start-ups say prices will come down, and for people wanting to have backup power storage in their home, it will be much cheaper to buy plug-in-ready batteries within appliances than installing stand-alone energy storage. By some estimates, it is 3 to 10 times more expensive to install equipment like home batteries, compared to the batteries themselves. Eventually, these companies plan to integrate their customers’ batteries into massive networks that represent many megawatts of flexible energy storage.

“We won’t stop at doing stoves,” says D’Amico. “You’ll get a number of appliances, and all of them will come with appropriately sized batteries. As you incrementally electrify your house, you get incremental energy storage. It’s like getting a Tesla Powerwall without ever getting a Powerwall.”

Backing up your home grid

Little affordable batteries could help countries leapfrog into a renewable future, rather than wait for utilities to invest billions of dollars in new transmission, better home connections and energy storage.

Right now, your appliances use little energy for most of the day. Yet each morning and evening, your home’s energy use spikes when water heaters click on or the oven fires up. Multiply this intense burst of electricity by millions of appliances. You can see the problem.

In the United Kingdom, there’s a name for this phenomenon: the kettle surge. During breaks in popular TV programs, millions of electric kettles turn on at once, leading to a massive, destabilizing surge of demand. To meet it, a dedicated “grid energy balancing” team at the national utility uses computer models to forecast electricity consumption, even tracking popular TV dramas. A standard soap opera episode might imply an extra 300 megawatts of power during breaks, but if a main character dies during the episode, the audience might need 600 megawatts or more.

Smoothing out spikes like this means the U.K. must run power plants on standby, or import huge volumes of energy from mainland Europe.

But small batteries could step up to the plate.

Stoves, heat pumps, washers and dryers. Even kettles. At a national scale, these could soak up cheap power when renewables are plentiful, and dispatch it during the peak hours in the mornings and evenings when electricity supplies are tight. As people swap gas for electricity, and less consistent wind and solar energy comes online, this will only become more valuable. It will help manage spikes — and maybe even earn you money from selling power to the grid or dodging peak electricity prices.

Energy companies and appliance manufacturers like Impulse and Channing Street Copper are already vying to manage the megawatts of power stored in millions of appliances.

It seems like a clear climate win. But since battery manufacturing is so energy-intensive, it’s not clear if installing so many batteries guarantees lower overall emissions. “It’s an open question still whether or not getting batteries into the home is on its face a decarbonization strategy,” Wyatt Merrill, who works on building electrification at the Department of Energy, told the climate podcast Volts. “It definitely has the potential to be. But when you think about the entire life cycle of mining lithium and developing the batteries and shipping them around, you really have a hole to dig out of.”

Still, economic forces may usher in a world of little batteries everywhere faster than we think. Priced at more than $10,000, large stationary batteries like Tesla Powerwalls — another solution to support a clean grid — remain too expensive for many homes. With utilities imposing time-of-use rates and curtailing homeowners’ ability to sell solar electricity back to the grid, storage in your home will only become more valuable.

Kyri Baker, an assistant professor of engineering at the University of Colorado at Boulder, says these new appliances can deliver low-cost energy storage at home while building the grid’s capacity to absorb clean, excess energy.

“It’s going to be a game changer,” says Baker. “It really makes financial sense to absorb this [electricity] locally. The best way is to let appliances do it.”

correction

A previous version of this article incorrectly referred to the stove batteries as lithium ion phosphate batteries. They are lithium iron phosphate batteries. The article has been corrected.

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