Clean tech companies have traded flat on aggregate this year versus the S&P 500’s 2-percent gain, a sharp contrast from when it was the best-performing energy subsector. Yet clean tech "remains a stock picker’s market,” Raymond James analyst Pavel Molchanov said in a Thursday note. First Solar, Inc. stock is down 22.6 percent in the first half of 2018, while Enphase Energy Inc is up 197 percent. Molchanov made his latest picks Thursday, upgrading Advanced Energy Industries, Inc. and downgrading Clean Energy Fuels Corp and NextEra Energy Partners LP . Source