In the following video, Motley Fool energy analyst Joel South takes a question from a Fool reader, who writes: "What are your thoughts on natural gas as a transportation fuel? Can Westport Innovations (WPRT 0.45%) and Clean Energy Fuels (CLNE -1.75%) fill this niche?"
Premium Investing Services
Invest better with The Motley Fool. Get stock recommendations, portfolio guidance, and more from The Motley Fool's premium services.