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. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.