A novel hybrid biomass-solar driven triple combined power cycle integrated with hydrogen production: Multi-objective optimization based on power cost and CO2 emission

Utilization of hybrid renewable resources in supplying clean energy is a new idea which helps to fulfill individual drawbacks of each renewable source. In this work, an innovative triple combined power cycle driven by hybrid biomass-solar energies is proposed, analyzed and optimized from the exergy, economics, and environmental standpoints. In order to fulfill the intermittent nature of solar energy, it is used for hydrogen production (via Proton Exchange Membrane (PEM) electrolyzer supplied by electricity from Photovoltaic-Thermal (PVT) panels) which is injected into a post-firing combustion chamber of the gas turbine. The proposed system consists of a biomass fueled gas turbine combined with a closed Brayton cycle and a Rankine cycle as the bottoming cycles. To examine the system performance, thermoeconomic evaluation is carried out and multi-objective optimization is performed to find the optimum operating conditions based on Levelized Cost Of Electricity (LCOE) and CO2 emission. The results revealed that, incorporation of solar-based hydrogen production with the biomass-based gas turbine results in a significant decrease in CO2 emissions and biomass consumption as well as increase in power generation capacity. However, it brings about a decrease of exergetic efficiency (due to the large exergy destruction in PVT and PEM electrolyzer) and an increase of LCOE (due to the additional expenditures imposed by PVT panels and PEM electrolyzer). Under the best operating conditions based on multi-objective optimization, the proposed triple combined cycle attains exergy efficiency of 30.44% with a LCOE of 61.37 $/MWh, and CO2 emission of 0.4579 kg/kWh.