A systematic comparison on power block efficiencies for CSP plants with direct steam generation

The increase of the process temperature of concentrating solar power plants above the degradation temperature of thermal oil (400 °C) opens the way for increased power block efficiency and thus reduced cost of electricity production. Direct solar steam generation is one technical option to follow this path. The paper presents different power block designs for direct steam generation parabolic trough and linear Fresnel power plants. Based on a systematic modelling approach, results for efficiency gains are derived and compared against a reference case of an oil-based plant. The results show that different reheat configurations are feasible and that efficiency gains in the range from 4 to 6% can be expected based on todays or near future solar collector technology