PROME3THE2US2 Project

Energy conversion from concentrated solar systems is presently performed by semiconducting cells in Concentrating Photovoltaics (CPVs) and by a thermodynamic heat transfer to high operating temperature engines in Concentrating Solar Plants (CSPs). In both cases, the economics of the solar plant are still not competitive with electricity generated from conventional fuels, since the cost of solar electricity is typically twice or higher. One strategy to increase cost effectiveness and make concentrated solar electricity more competitive is to develop technologies characterized by a higher conversion efficiency. It corresponds to development of multi-junction cells on the CPV side (above 40%) and to operations at higher temperatures combined to advanced thermodynamic cycles on the CSP side (over 40% at a converter-level). The resulting system efficiency is in the 25-30% range. A parallel approach is reducing the installed plant cost by developing simpler, lower cost alternatives to plant components such as cheaper reflector materials and optimized tracker mechanics. One aspect of CSP that remains untouched is the heat-to-electricity converter. This conversion relies on proven heat engine technologies that have been developed for many decades for conventional power plants, such as Rankine (steam) and Brayton (gas) turbine cycles. In addition, a separate hightemperature receiver and a heat transport system for introducing the heat from the receiver into the thermodynamic cycle are required. Thus, the thermo-mechanical conversion approach leads to technologically complicated systems that add a significant contribution to the cost, complexity, operational and maintenance requirements of the solar power plant.