Climate Central: June marked two huge milestones in renewable energy in the U.S., with Hawaii and Vermont both passing laws that put in place the nations most ambitious renewable energy goals. Electricity generation is the nations largest emitter of climate-changing greenhouse gases, leading many states to set goals for how much of their power should come from low-carbon renewable energy. Today, 29 states have laws mandating a certain portion of their power to be generated from renewables as a way to combat climate...