Hydrogen Blending and Partial Load Control Modeling: Updated Designs and Simulations

As discussed in Harper et al. [1], EPRI has been investigating potential issues in real gas turbine hydrogen blending and flexible load control. Earlier research and operations have shown that gas turbines operating under variable partial load may experience more operational issues. This is partly due to the demands placed on the control system by a gas turbine operating at highly variable efficiencies and load. Demonstrations of hydrogen blending have been conducted on many gas turbines [2-6]. However, these demonstrations have generally not been completed under “real world” flexible loading operations of a gas turbine. It is highly likely that if hydrogen is utilized in large capacities in gas turbines in the future, it will be under variable and highly flexible loading operations due to the costs of hydrogen and the prevalence of Variable Renewable Energy (VRE, Solar, Wind) in that potential future scenario. As detailed in Harper et al. [1], without hydrogen, gas turbine peaker operation can be highly variable with many starts and load changes in short periods of time. The initial study found that traditional load control techniques may lead to operational issues in meeting grid demands and gas turbine operational requirements for robust operation when hydrogen blending is added. This work expands on the previous study of Harper et. al [1] by examining additional scenarios. The gas turbine model and control system have been updated to reflect the timescales of state changes (pressure, temperature, and power) more accurately with changes in boundary conditions (fuel/air flow). This is combined with an evaluation of an updated Model Predictive Control (MPC) architecture designed to control the blending rate, load, and combustion firing temperature accurately. These system design changes are detailed along with simulation results.