California has become the first U.S. state to approve plans to require newly built homes to include solar equipment. The state’s Energy Commission voted 5-0 to approve the new rules, which are to take effect in 2020. The rules will cover most newly built residential buildings up to three stories high. The move is California’s latest step aimed at reaching renewable energy targets and reducing greenhouse gas emissions. California has set a goal of filling half of its electricity needs with renewable energy by 2030. Officials said they had reached 30 percent by the end of 2017. The state’s Governor, Jerry Brown, plans to hold an international climate meeting in September.