Conversion of low-grade heat to high-quality energy such as electricity using the Rankine cycle poses serious challenges. When such conversion is possible, it is invariably expensive or unacceptable due to environmental concerns associated with the working medium. The low-grade heat can either be from exhaust systems or from solar radiation. Thus, the topic addresses a very useful subject, combining energy efficiency and renewable energy. Although high-grade heat recovery and energy conversion is a mature technology widely covered by the literature, low-grade energy conversion, especially using thermodynamic cycles, has not been sufficiently addressed to date. This paper addresses the feasibility of a low-grade heat-driven Rankine cycle to produce power using a scroll expander, a low toxicity, low flammability, and ozone-neutral working fluid. A cost benefit analysis of the recommended system shows that it is a viable option for solar power generation, at about one-third the cost of a comparable photovoltaic system. Copyright (c) 2008 John Wiley & Sons, Ltd.