SRS 2019: Dean's Award, Engineering - Edwin Gonzalez

Numerical Model of a Concentrated Solar Power Combined Cycle Plant with Sensible Thermal Energy Storage:

Energy storage solutions are important to address the imbalance of renewable energy resources and the net energy demand in the state of California; an effect known as the “duck curve.” The presentation at the SRS was for a numerical code, modeling a rock-filled thermal energy storage system. This storage system was developed to be used in conjunction with a concentrated solar power combined cycle power tower plant. The numerical model of the hybrid solar combined cycle was previously developed at the Combustion and Solar Energy Lab.

The strategy explored here is to put the storage unit after the gas turbine in a combined cycle plant and capture the gas turbine exhaust. The Brayton cycle is operated during the day and is powered by a mix of fuel and solar energy. The bottoming Rankine cycle is operated during the night and is powered by the energy in the thermal energy storage.

The objective was to compare the energy production of the combined cycle with and without energy storage. When comparing a 12-hour combined cycle solar/fuel operation to a 24-hour combined cycle solar/fuel with thermal energy storage operation, the energy generation was comparable. Of course, the 24-hour operation has lower energy generation due to energy losses but demonstrated that the storage can dispatch comparable amounts of energy outside of the solar peak period.