Application of Molten Salt Electrical Heaters to Increase the Flexibility of CSP Plants’ Power Block

Abstract

The transforming grid profiles require concentrated solar power (CSP) plants to operate in a dispatchable and flexible manner; however, the allowable minimum load of the power block exerts a limitation on the operation range. This study proposes using molten salt electrical heaters to lower the minimum electricity output of CSP plants. In this regard, three configurations of the molten salt electrical heaters, 1) in parallel to the receiver, 2) in parallel to the hot tank, and 3) in series to the receiver, are investigated with six grid and three revenue scenarios. The system is assessed for Fuerteventura. The findings validate that the application of the molten salt electrical heaters, particularly through Configurations 1 and 3, enhances a) the flexibility characteristics of the CSP plant with up to a 10.2% increase in demand coverage factor, an 84.6% decrease in start-up instances, and a 41.4% increase in operating hours; and b) economic performance with up to a 35.7% increase in gross profit.