"Solar panels will be a required feature on new houses in California, after the state's Building Standards Commission gave final approval to a housing rule that's the first of its kind in the United States.
Set to take effect in 2020, the new standard includes an exemption for houses that are often shaded from the sun. It also includes incentives for people to add a high-capacity battery to their home's electrical system, to store the sun's energy.
"These provisions really are historic and will be a beacon of light for the rest of the country," said commissioner Kent Sasaki, according to The Mercury News. "[It's] the beginning of substantial improvement in how we produce energy and reduce the consumption of fossil fuels."
The rule marks a new phase in California's environmental policies, which have often set trends and established standards nationwide. The state has set the goal of drawing 100 percent of its electricity from renewable energy sources and sharply reducing greenhouse gas emissions."