As of the end of 2018, 29 states and the District of Columbia had adopted renewable portfolio standards (RPS), polices that require electricity suppliers to source a certain amount of their electricity from designated renewable resources or eligible technologies. Three states—Maine, New York, and Ohio—have updated their RPS since May 2019. As a result of their updates, Maine and New York joined California, Hawaii, Nevada, New Mexico, and the District of Columbia in requiring 100% clean electricity by 2050.
