Session: 03-06 Design for sustainability

Paper Number: 127796

127796 - Thermodynamic Optimization of Load-Following Operation in a Decarbonized Combined Cycle Power Plant Under Net-Zero Scenarios 

This paper has been conceived as continuation and development of the previous ones (GT2022-83250, GT2023-103511), in which post-combustion capture (PCC) by means of mono-ethanolamine (MEA), exhaust gas recirculation (EGR) and hydrogen co-firing have been applied to a 2x1 combined cycle (CC), chosen as representative of existing power plants, with the aim of fulfilling the goal of net-zero carbon emissions. The main novelty lies in the load-following operation mode, so that power generation is adjusted as demand for electricity fluctuates throughout two typical days in summer and winter, with a time step of 1 hour.

Thermodynamic investigation has been deepened to optimize the off-design performance of the CC when PCC is combined with EGR, by varying the fuel supply: 100% NG is compared with 65% vol hydrogen co-firing, consistently with gas turbine H₂-capability. More specifically, a multivariable optimization problem was solved to find the maximum net electric efficiency as a function of the following decision variables:

- load of each gas turbine, in the range from minimum turndown to full load;

- EGR rate, in a range that depends on the fuel type: [0; 0.4] for 100% NG and [0; 0.6] for hydrogen blending;

with the constraint of net power output equal to electricity demand, for given environmental conditions.

The ultimate goal is to minimize the energy penalty due to decarbonization under the assumption of flexible generation, taking the integration of MEA CO₂ capture into the NG-fired CC as a benchmark. Overall, the discussion of the results fits the current challenging context, in which gas-fired generation and, more generally, dispatchable resources are sharply reduced during daylight hours, then conversely ramped up at sunset.

Presenting Author: Silvia Ravelli University of Bergamo

Presenting Author Biography: Silvia Ravelli took the Ph.D. in Technology for Energy and Environment in 2006 at the University of Bergamo - Department of Industrial Engineering. She is associate professor of Energy Systems at the same University since June 2017. The research activity focuses on power plant modelling and simulation, even through CFD techniques.

Authors:

Silvia Ravelli University of Bergamo