In this edition of The Motley Fool's "Ask a Fool" series, Motley Fool Rule Breakers analyst Simon Erickson takes a question from a reader who asks: "Any insight as to where fuel cell technology is heading in the Fool's opinion?"  

Simon focuses on the recent hot streak of Plug Power (NASDAQ:PLUG), whose stock price has risen nearly 500% after the company announced deals with Air Liquide and FedEx (NYSE:FDX).  He offers two things that investors should keep an eye on, as well as his take on the stock right now. 

Simon Erickson has no position in any stocks mentioned. The Motley Fool recommends FedEx. 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.