Levelized cost analysis of microturbine with exhaust gas recirculation and CO2 capture system in Mexico

Abstract

The effect on the Levelized Cost of Electricity (LCOE) by implementing CO2 capture on a 200 kW microturbine installed at the National Institute of Electricity and Clean Energies (Spanish acronym INEEL) was evaluated. Increasing the CO2 concentration in exhaust gas is a potentially effective method to reduce the high electrical efficiency penalty caused by using the capture system with chemical absorption. In this paper the LCOE achieved with and without Exhaust Gas Recirculation (EGR) of CO2 were compared. Data obtained in experimental tests of the microturbine operating with diesel as fuel on-site were used to validate the simulated performance in Thermoflex, since there is currently no existing natural gas infrastructure. It was assumed that the performance would be similar to the manufacturer's data, although for each fuel the combustor was different. Natural Gas was used in the simulation at 100% load. The CO2 capture plant was simulated using Aspen Hysys with MEA as the solvent at 90% capture of CO2 and 90% purity. Simulations helped to size the equipment and calculate the investment cost of the CO2 capture and EGR systems. The LCOE was compared for CO2 capture and an EGR system at different ratios, showing that the use of EGR with a small scale capture system reduces the LCOE, while reduces the heat duty in the reboiler due to the increase of CO2 in exhaust gases.