UC Irvine

While advancement of power generation and grid management technologies has enabled their broader applications, recent changes in climate are projected to impose obstacles to performance and operation of the systems employing these technologies. As more renewables are prioritized over fossil fuels to alleviate changes in climate, the power systems are in need of further research to help meet public and environmental demands by complementing renewable intermittency. In this thesis, the combined-cycle plant technology was modeled in the MATLAB/SIMULINK and verified at two different scales: 1) a 19MW UC Irvine central power plant; 2) a 600MW utility-scale power plant.

Three scenarios were generated using the Holistic Grid Resources Integration and Deployment (HiGRID) tool with the renewable penetration percentages set according to the original California Renewable Portfolio Standards (RPS): 33%, 50% and 80%. Each scenario presented how various power generating classes contribute to electricity demands for a year-long period. For the scope of this study, load-follower power plant contributions to the general load profile for a week-long period were extracted, normalized and input into the utility model for simulation.

The simulation results demonstrated possible consequences from increasing the renewable penetration to the grid. With the increasing penetration, the natural gas combined-cycle power plant needed to operate more dynamically as a load-follower to complement the renewables. The more dynamic operation of the power plant resulted in decrease of its efficiency from 63% to 44% and to 36% and its capacity factor from 75% to 59% and to 34% for the three scenarios, respectively.