Tower Technology Cost Reduction Approach after Gemasolar Experience

Abstract The purpose of this paper is to describe the mandatory approach to the Solar Power Tower Plant (SPTP) with molten salts receiver and Thermal Energy Storage (TES), from the energy cost reduction point of view, based on Gemasolar reference (see [4] ) and SENER's broad and successfully experience on CSP market (up to date SENER has been involved in 25 different CSP projects). During the last five years, and taking into account the great experience of Gemasolar plant proven in commercial operation since April 2011, (the first commercial high temperature molten salt SPTP, with 19.9 MWe gross power, molten salt central receiver, 15 h storage and 2650 heliostats solar field designed with operating temperatures for cold and hot tanks of 290 and 565 °C), SENER has been concentrated on developing new future generation of SPTP with TES system, under the specific objective of energy cost-reduction. SPTP scale-up, together with research & development on key components and industrialization, are the key aspects to get this objective. Especially important are the lessons learned regarding plant operation and annual solar-to-net-electric efficiency. With 3 years of commercial experience (since April 2011), SENER has a deep knowledge of the behavior of the plant under all possible operating conditions (start up, full load, transient, cloud passage, shutdown), including the performance of each particular component (heliostats, receiver, thermal storage, power block, parasitics). As a result of this experience, SENSOL software – a tool completely developed by SENER for the techno-economic optimization of CSP projects, see [1] and [2] – has been fine-tuned with the results of the plant, achieving a high degree of accuracy in performance simulation. The above indicated facts represent the state of the art of the molten salt tower technology and will be presented during the symposium. This paper deals with the following issues: molten salt SPTP with TES scale-up; next generation for Solar Power Tower Plants with storage: cost reduction approach; Gemasolar experience gained and used in the future SPTP design: effect on performance, cost and reliability.