In October, the city council of Santa Monica, California, approved a sweeping ordinance requiring all newly built single-family homes, as well as duplexes and low-rise multifamily buildings, to have zero net energy (ZNE) consumption. According to the 2016 California Green Building Standards Code (CALGreen), whose definition was adopted for the ordinance, a ZNE home is one that produces as much renewable energy on-site as it consumes yearly. The ordinance is the first of its kind in the world, officials say.

The state of California already has an upcoming code requirement on the books for all new residential construction to achieve ZNE by 2020. But Santa Monica has often adopted its own ambitious policies on environmental issues as a way to drive change elsewhere, says Dean Kubani, the city’s chief sustainability officer. “Many practitioners and cities in California aren’t aware this code change is coming in 2020—or they don’t believe the state will be ready,” he says. “Taking this action now gives us a pathway toward this goal, helps raise awareness, and drives home the importance of the issue.”

The ordinance must be given the green light by the California Energy Commission (CEC), a process that includes a public comment period. Kubani estimates that it could officially go into effect as early as late February 2017. Once it passes, all permit applications for new residential construction in Santa Monica will need to comply with ZNE. Projects that are in schematic design at the time the ordinance passes but not in compliance would need to be modified, while those with approved permits would be grandfathered in. The new measure will be enforced via Santa Monica’s existing building code, the same process the state intends to use in 2020. “It will become a model for other cities,” says California asssemblymember Richard Bloom.

Attaining ZNE status for newly built homes in sunshine-abundant California is “absolutely achievable” by 2020, says Kubani. Solar electric and solar thermal systems have been steadily decreasing in price for several years, and as Santa Monica developed its ordinance, it worked closely with the CEC and local utilities, and collaborated with local design and construction firms to assess its technical and cost feasibility.

Even so, housing developers aren’t uniformly prepared for the code change. “Some forward-thinking companies are seeing ZNE homes as a market opportunity,” says Dominique Hargreaves, executive director of U.S. Green Building Council’s Los Angeles chapter. “But many others are lagging behind, convinced that the state will have to extend the timeline so the market can catch up.” She’s encouraged by research and planning efforts in and around L.A. County to retrofit existing housing communities to achieve ZNE status, another move that would curtail the effects of climate change.

But in Santa Monica itself, practitioners are used to being held to tough standards. “The city has always set the bar high for energy efficiency,” says Angela Brooks, principal of Los Angeles firm Brooks + Scarpa and 2018 president-elect of the AIA’s Committee on the Environment (COTE). Her firm has designed several energy-efficient affordable housing projects in Santa Monica, including Colorado Court in 2000 and Pico Place in 2014. “Sixteen years ago, we put solar panels on Colorado Court to prove the technology could power a multifamily building. Now the performance targets we achieved with that demonstration project are actually written into Title 24 [the state’s energy code].” And these stricter codes have helped the industry learn to design more and better energy-efficient homes and buildings, she adds.

The ZNE ordinance is just one of Santa Monica’s strategies for achieving its long-term goals for climate-change mitigation, including releasing zero carbon by 2050. “Ideally, we’ll show the country and world that ZNE buildings of all kinds are practical and affordable, and eventually they’ll become the new normal,” says Kubani.