Within our theme Enphase Energy, a company that is best known for its solar micro-inverters has been the strongest performer, rising by about 68% year-to-date. First Solar, a company that sells solar panels and develops utility-scale PV power plants, has also fared well with its stock rising by 57% year-to-date. On the other side, NextEra Energy NEE, one of the largest U.S. utilities by market cap and the single largest owner of solar generation capacity outside China, has been the weakest performer with its stock down by about 1% year-to-date.