What happened The sun is shining brightly on solar stock investors Wednesday, with shares of solar panel installer SunPower (NASDAQ: SPWR), solar module-maker JinkoSolar Holding (NYSE: JKS), and solar inverter inventor Enphase Energy (NASDAQ: ENPH) all soaring more than 10% in morning trading. As of 12:45 p.m. EST, SunPower stock was still up 9.8%, Jinko was up 11.2%, and Enphase was up 9.1%. Why? That's something of a mystery. Image source: Getty Images. So what None of the usual catalysts for big, 10%-plus stock moves are apparent today -- no analysts are upgrading solar stocks nor raising price targets on the same. None of the three have announced earnings -- or really announced much of anything at all. The closest thing I see to a catalyst for today's stock price gains is the fact that, back on Monday, Goldman Sachs raised its price targets on two of the three stocks named, positing a $23 target price for SunPower and a $127 price for Enphase, according to TheFly.com. Now what Goldman Sachs' comments accompanying those two price target hikes may provide a clue as to why solar stocks continue to show strength today. At the time, Goldman cited "President-elect Joe Biden's proposed clean energy policies" as its greatest reason for optimism in the solar sector, and predicted that investors will see faster deployment of solar panels in coming years. Assuming Goldman Sachs is right about this, of the three stocks named, I have to conclude that Enphase is the best way to play the trend -- because of the three stocks named, it's the only stock that is currently generating cash from its business. According to data from S&P Global Market Intelligence, over the past 12 months, both SunPower and Jinko have reported burning cash. Enphase, in contrast, has generated a total of $215 million in positive free cash flow. Granted, investors can have differing opinions on whether even $215 million in FCF justifies a $15.5 billion market capitalization for Enphase (it works out to a 72 times multiple to FCF). But beggars can't be choosers. Of the three stocks named, Enphase is the closest thing we've got to a stock trading for fair value -- even if it isn't really close at all. 10 stocks we like better than SunPowerWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and SunPower wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of October 20, 2020 Rich Smith has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.Source