Governments looking for ways to slash fossil fuel use and meet their greenhouse gas reduction goals are turning to their increasingly carbon-free grids to decarbonize buildings.
The Board of Supervisors in Marin County, California recently approved energy-efficiency updates to its green building requirements that include provisions providing a compliance pathway for all-electric buildings. The updated standards apply to new buildings in unincorporated areas of the county.
In an interview, Alice Zanmiller, sustainability planner with Marin County’s Community Development Agency, said the move to encourage all-electric buildings is directly connected to the increased availability of renewable electricity in the county.
The baseline electricity mix offered by MCE, the community-choice aggregator that supplies electricity to Marin County and more than a dozen other San Francisco Bay Area jurisdictions, is 50 percent renewable. Customers can opt for the 100 percent renewable energy “Deep Green” option for a slight premium.
With a much cleaner grid, said Zanmiller, the county “recogniz[ed] that these new buildings are really opportunities to reduce our ongoing natural-gas use.”
“And for homes that do want to be mixed-fuel homes,” she added, “we’re requiring higher levels of efficiency to reduce the natural-gas use.”
Marin County will similarly require higher levels of efficiency for new large homes. Under the new standards, mixed-fuel homes larger than 4,000 square feet must be 35 percent more efficient than required under state code and generate as much electricity onsite as used in a year. All-electric large homes must be 20 percent more efficient than state code and install at least 2.5 kilowatts of solar.
The all-electric option could be particularly effective in reducing fossil fuel use and emissions in western Marin County, said Zanmiller. Many homeowners there do not have natural-gas service and use propane instead.
“We’re hoping electricity will be a good alternative, especially for folks who live in areas without natural gas,” said Zanmiller. “We’re starting to look at our building code less from an energy-use perspective than from the associated carbon content.”
This week, the California Energy Commission (CEC) will vote on whether to permit Marin County to implement its updated building energy-efficiency standards. California law permits cities and counties to adopt building energy standards more aggressive than the state baseline if the standards are deemed cost-effective and are approved by the CEC.
Zanmiller said Marin County’s inclusion of an all-electric compliance option was modeled on an all-electric exception to the City of Palo Alto’s Energy Reach Code that took effect in 2017. For both the Marin County and Palo Alto codes, “all-electric” buildings mean those in which electricity is the only permanent source of energy for space and water heating, space cooling, cooking and clothes drying.
Building a market for all-electric homes
Despite the pioneering efforts by Marin County and the City of Palo Alto to promote the construction of all-electric buildings, it’s still a nascent market.
Greentech Media reported this spring on the challenges that one San Francisco Bay Area family faced when it set out — successfully, in the end — to swap all of its gas-burning appliances for electric models.
Marin County is eager to raise awareness that all-electric homes are feasible today. The county was recently awarded a grant of just under $300,000 from the Bay Area Air Quality Management District to launch a building-decarbonization pilot project.
“We’ll provide direct incentives to homeowners across Marin County who swap out natural-gas appliances for high-efficiency all-electric ones, such as heat pumps (water and space) and induction cooktops,” said Zanmiller.
She added, “We’re hoping the outcome is that folks will understand the steps, barriers and resources available to make their existing house all-electric. We’ll complete a survey and report out on lessons learned and resources developed through the process to share with other local governments.”
Legislation now before the California legislature could accelerate the creation of a market for all-electric, zero-carbon homes. AB 3232, which passed out of the Assembly on May 29, would require the CEC to assess the potential for California to reduce greenhouse gas emissions from buildings by 40 percent by 2030.
The next day, the State Senate passed SB 1477, which would establish an incentive program for low-carbon space and water heating equipment modeled on the California Solar Initiative, which helped to establish the rooftop solar market in the state. Both bills must first be approved by lawmakers in their current chamber before being sent to Gov. Jerry Brown.
California’s new solar roof mandate is likewise seen as a necessary step in the transition to electrified, zero-emission buildings in the state.
Alice Zanmiller sees in all the activity a determination to tackle emissions from buildings, the source of one-quarter of California’s greenhouse gas emissions.
“It’s an exciting time,” she said. “The conversation has shifted quickly.”
She added that even two years ago, she hadn’t really thought much about building electrification.
But “as more jurisdictions around the Bay Area and statewide have community-choice aggregation, and that electricity continues to get cleaner,” she said, “it’s a really good opportunity and time for it.”
Local Governments Look to All-Electric Buildings to Reduce Greenhouse Gas Emissions, by Justin Gerdes, Greentech Media, June 11, 2018.