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This work evaluates concepts of hybridizing the molten salt central receiver design to recover spilled energy in an effort to reduce the electricity cost. The hybridization is done using existing technologies requiring marginal improvements. A simplified assessment is done to arrive at a target cost of two spillage recovery system without changing the prevailing levelized cost of electricity (LCoE) from the reference solar power plant. The target cost of the spillage recovery system using feedwater heater panels is $49M, whereas for concentrated photovoltaic modules, it is $40M. Integrating such systems with the tower type receiver below the target price is expected to reduce the LCoE of the plant. However, project specific conditions and requirements may also play an important role and should be taken into consideration with a more detailed overall plant level study to determine the feasibility of the hybridization concepts in a specific project.

A solar receiver undergoes frequent transients events and the nature of these transient events is very different from conventional thermal power plants. The SRSG (Solar Receiver Steam Generator) operates during the day when heat from the sun is available and is shut-down during the night. Along with the daily start-up and shut-down, it also undergoes various other transient events including short or long cloud events followed by hot-start, partial load transient during light cloud events, cold start-up transients (after extended shut-down events) and failure modes. The operation and control strategy for the SRSG should incorporate safe operation during all the transient events while optimizing on power generation. It is therefore important to model the SRSG and study the dynamic response of the SRSG under various transient conditions. This paper discusses modeling of Alstom SRSG using the APROS dynamic simulation platform. The paper describes in detail various components of high pressure, high temperature SRSG along with the need for transient modeling during the design phase. It provides details of various transient events that were simulated along with a discussion on the simulation results. The paper highlights the optimized modes of operation procedure developed using transient modeling along with control strategies.