Over the next few years, residents of select California neighborhoods may start getting phone calls and mailers from gas utilities and community organizers offering an unexpected proposition: Would you like to ditch gas and switch to all-electric appliances instead?

That’s the future envisioned by the environmental groups backing SB 1221, a bill passed in the final days of California’s legislative session and aimed at giving utilities permission to launch up to 30 ​“zonal decarbonization” projects.

If signed by Governor Gavin Newsom (D) this month, SB 1221 would order state regulators to create a path for utilities to propose pilot projects that could offer entire neighborhoods the option of switching from gas-fired furnaces, water heaters, dryers, and stoves to all-electric appliances.

Even if SB 1221 is signed into law, a lot needs to happen in the next two years for its zonal decarbonization projects to materialize, said Beckie Menten, senior regulatory and policy specialist at the Building Decarbonization Coalition, one of the nonprofits backing SB 1221. But given the tight timeline the state faces for cutting carbon emissions from its buildings, the bill is one of the best options available, she said.

“We see this as a really important affordability measure going forward, because it helps stop the gas-rate spiral we see happening,” Menten said, referring to the challenge facing gas utilities in not only California but also New York, Illinois, Massachusetts, and other states that have aggressive carbon-emissions reduction targets.

Simply put, gas utilities spend billions of dollars per year repairing and replacing gas lines. Gas customers bear the cost of repaying those investments in the form of charges on their monthly bills; sometimes those costs are spread over as many as 50 years. But the volume of fossil gas that utilities sell must decline dramatically over the next two and a half decades in states with strong decarbonization targets — well before much of the cost of current pipeline investments is due to be paid off.

A 2021 report from consultancy Brattle Group found that the cost of these ​“unrecovered” investments could add up to $150 billion to $180 billion for U.S. gas utilities over the coming decade.

That puts pressure on policymakers to find ways to reduce gas pipeline investment today, without endangering the safety of the network or denying customers access to energy. Zonal decarbonization accomplishes both those goals by shifting the money utilities would have spent on pipelines into helping customers leave the gas system and electrify instead, Menten said.

“It helps decrease investment in the gas system and helps customers who might have trouble affording electric appliances on their own,” she said.

A variety of approaches to gas system decarbonization are being tested in states including Colorado, Illinois, Massachusetts, New York, and Washington. In the U.S. Northeast, utilities are building thermal energy networks — pipelines that circulate liquid from deep underground to near the surface to improve the efficiency of heat pumps in homes and businesses. Colorado utility Xcel Energy’s Clean Heat Plan will direct $440 million over the next three years toward reducing emissions from fossil gas delivery, primarily via electrification and energy-efficiency measures.

In California, utility Pacific Gas & Electric is already engaged in smaller-scale​“targeted electrification” projects, in which select numbers of customers served by gas lines that would be costly to repair agree to switch to all-electric heating and appliances. But PG&E’s work has been limited to date by its obligation to get 100 percent customer buy-in for making this switch.

SB 1221, by contrast, would allow zonal decarbonization projects to proceed if 67 percent or more of all affected customers agree to it, said Kiki Velez, an equitable gas transition advocate for the Natural Resources Defense Council, one of the bill’s primary backers. That can allow utilities like PG&E to avoid the risk of their projects being stymied by one or two holdouts — although utilities must also be cautious about alienating customers who prefer using gas, she noted.