Unlike other articles in this issue, here we address not so much how to manage a demonstration project as what to demonstrate and when. Specifically, the article identifies five characteristics of successful large-scale technology demonstration programs, based on experience with fuel cell technologies: 1) a robust technology that has not yet significantly penetrated the marketplace; 2) reduced uncertainties in R&D (in this case, movement on codes and standards impacting design, permitting, and installation); 3) the active involvement of private sector advocates in sponsoring demonstration activities and brokering partnerships; 4) a strong federal role; and 5) economic incentives. Each of these will be discussed in turn, supported by examples. The article also describes fuel cell technologies and offers guidance on potential applications for both power generation and transportation.