The recent decision by the California Energy Commission to mandate solar on all new residential buildings starting from 2020 has had a noticeable impact on GTM Research’s solar forecast for the Golden State, bumping it up by 14% over 4 years, or around 650 megawatts (MW).

Last week, after rumors and speculation had all but confirmed it, the California Energy Commission (CEC) announced that it would approve changes to the 2019 Building Energy Efficiency Standards which would mandate all new residential buildings — including new homes, condos, and apartment buildings — be built with solar PV installations of some sort, or tap into a community solar project.

The move was intended to help cut energy use in new homes by over 50% and is expected to cut greenhouse gas emissions equivalent to taking 115,000 cars off the roads.

“Under these new standards, buildings will perform better than ever, at the same time they contribute to a reliable grid,” said Commissioner Andrew McAllister, who is the Energy Commission’s lead on energy efficiency. “The buildings that Californians buy and live in will operate very efficiently while generating their own clean energy. They will cost less to operate, have healthy indoor air and provide a platform for ‘smart’ technologies that will propel the state even further down the road to a low emissions future.”

“This is an undeniably historic decision for the state and the US California has long been our nation’s biggest solar champion, and its mass adoption of solar has generated huge economic and environmental benefits, including bringing tens of billions of dollars of investment into the state,” said Abigail Ross Hopper, president and CEO of the Solar Energy Industries Association. “Now, California is taking bold leadership again, recognizing that solar should be as commonplace as the front door that welcomes you home.”

GTM Research published a new analysis late last week which revealed what it expects to be the upside to this new requirement, specifically, the base-case residential solar PV forecast increased by 14% between 2020 to 2023, which works out to be an increase of about 650 MW.

GTM’s analysis is based on the Commission’s prediction that nearly 75,000 new homes will be built across California in 2020 alone and could help the state overcome a recent period of sluggish residential solar growth. GTM also note that their forecasts are a baseline and that there is greater potential available, but it will depend on what size solar addition becomes the norm for new construction and the segment of new houses that are eligible for exemption — those that may simply be incompatible or built in the shade of buildings or trees. Additionally, GTM’s new analysis does not apply to multi-family housing units, although GTM typically excludes these from its residential solar forecasts anyway.