| Strengths & Weaknesses
| Future Development
| Vendors |
Stirling engines are an old but unperfected technology produced in limited numbers for niche market applications. Unlike other distributed generators, Stirling technology has not undergone a robust research and development phase, and as such, the performance of commercial units does not represent the potential for this technology.
STM Power (formerly Stirling Thermal Motors) has a 25 kW unit with current electrical efficiency of approximately 30%, though the goal is to increase this efficiency to greater than 34% with more development. Other companies report electrical efficiencies in the range of 25 to 30%. Overall, the electrical efficiency of current Stirling engines is in the range of 12 to 30%.