Renewable energy from wind and solar is now competitive with the grid, opening up a trillion-dollar market for investors. Leases from SolarCity (SCTY.DL) or SunPower (SPWR -1.28%) with $0 down make solar power affordable and economical for homeowners. When added to Tesla Motors' (TSLA 11.85%) energy storage made at its gigafactory, the possibilities for disrupting the grid improve tremendously. 

Then there are massive power projects from First Solar (FSLR -1.47%), which are being passed down to new YieldCos like NRG Yield (CWEN -1.02%)

Motley Fool solar analyst Travis Hoium covers why this space is so exciting for investors and how they can play this billion-dollar opportunity.