Warren Buffett is one of the largest renewable energy investors in the world, but he doesn't invest in the space because it's clean, he invests because he can make money. Buffett's Berkshire Hathaway (NYSE:BRK-A)(NYSE:BRK-B) has spent $15 billion building and buying wind and solar farms because they'll pay him consistent cash flows over years, much like a bond. 

He's bought projects from SunPower (NASDAQ:SPWR) and First Solar (NASDAQ:FSLR) that come with long-term power purchase agreements and predictable rates of return. But spending billions of dollars on renewable energy plants isn't possible for nearly anyone else. 

That's why the YieldCo is a way you can invest in renewable energy without being a billionaire. The first of these to hit the market was NRG Yield (NYSE:NYLD), which has been a huge hit for investors looking for yield. 

Solar specialist Travis Hoium explains you can invest like Buffett -- and there may be more opportunities to do so in the future. 

Travis Hoium manages an account that owns shares of Berkshire Hathaway, NRG YIELD INC, and SunPower. He personally owns shares and options of SunPower. The Motley Fool recommends Berkshire Hathaway. The Motley Fool owns shares of Berkshire Hathaway. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.