Operation of concentrating solar power plants with storage in spot electricity markets

Concentrating solar power (CSP) is a promising technology, which will most likely develop in some parts of the world in the near future. It is already being exploited in certain countries, such as the USA and Spain, where subsidy policies are granted to support its development. One advantage of this technology is the possibility of storing the received thermal energy, and using it later. This storage allows CSP plants to smooth the electricity production and to schedule it independently of the instantaneous solar resource. In this way, these plants may be considered as dispatchable, and therefore they can be more easily and efficiently integrated into the power grid. In an electricity market, this means fitting the production as much as possible to the spot price, which sets the system needs of energy. In this way, shifting part of its production to hours with more demand and higher prices maximises the revenues of the plant. This study proposes an optimisation method that aims to maximise CSP plant revenues by taking into account daily electricity prices. The model is independent of the technology used. The performed simulation cases with this model show that current Spanish subsidy policies reduce the incentive for the full use of CSP plant dispatchability.