If the bill passes, New York would join Hawaii, California, New Mexico, and Washington as the only states with 100 percent clean or renewable energy mandates ("clean energy," by the way, includes renewables as well as nuclear and fossil fuels with carbon capture). Puerto Rico and Washington, D.C., have also passed similar legislation. Nevada and Colorado have made it a goal to have a carbon-free energy system by 2050, but its not required, according to analysis by EQ Research. Jacobson says the New York bill's emissions targets are among the most aggressive of the state policies—a good thing, given how little time government reports say we have to drastically cut our emissions. "It's definitely an important step," says Jacobson. "I think you can always be more aggressive, but it'll make some rapid changes."