If the proposal were to become law, it would be the first such requirement in U.S. history
A California state senator his introduced a bill that would require the installation of solar power on new commercial and residential buildings statewide. If the proposal were to become law, it would be the first such requirement in U.S. history, according to a press release by Scott Wiener, the legislator behind the bill. The statewide mandate would be similar to a city law that Wiener wrote and helped pass in 2016 as a member of the San Francisco Board of Supervisors.
The board approved the city ordinance last year that required new small and midsized buildings in San Francisco to include solar. Some other California cities have enacted similar solar mandates.
According to current California state law, all new residential and commercial buildings up to 10 stories tall must have 15% of their roof area solar ready—defined as unshaded and free of obtrusions. The proposed new legislation would require that solar be installed on the 15% of solar-ready roof area. The solar mandate could be fulfilled by either photovoltaic or solar water systems.