This article examines the role and fit of emerging fuel cell power systems in the evolving energy service enterprise. The application opportunities for fuel cell power systems in retail energy service business scenarios in North America are examined and discussed, also with reference to opportunities in other countries. Opportunity market segments for fuel cells include combined heat and power, low-cost energy, premium power, peak shaving, and load management and grid support. Understanding the role and fit of fuel cell systems in evolving energy markets and the highest value applications is a major challenge for developers and government funding organisations. This article reviews the most likely adopters of fuel cell systems and the challenges facing each adopter in the target market segment. Adopters include generation companies, utility distribution companies, retail energy service providers and end-users. Key challenges include: cost of fuel cell based energy services, distribution and service channels, overcoming technology risk, understanding high-value markets and end-user needs, and the integration of decentralised energy systems within the electrical distribution system.