Rankine powerplant advantages are found to fit best applications that call for long maintenance free life, or where the heat energy is essentially free as in bottoming and topping cycles, or in special environments as undersea or space. Worthy applications suggested on the basis of potential market size and ability to satisfy customer imposed cost and performance are: automotive and tank accessory power systems (APS), transportable refrigeration, portable power supply (GPS), standby power, remote site power, and home air conditioner drive. The automotive APS and a 1 1/2 kWe GPS are further analyzed. The APS can offer attractive features to the automobile user, including the possibility of reducing pollution from spark ignition engine. The GPS is an example showing high cost effectiveness for long operating times. It is recommended that marketing and cost studies continue, and that working fluid and heat exchanger technologies be accentuated.