Design and energy, exergy, and exergoeconomic analyses of a novel biomass-based green hydrogen and power generation system integrated with carbon capture and power-to-gas

The conversion of thermal energy into electrical power through combustion in combined cycle power plants is a prevalent method of energy conversion. Sustainable energy management requires effective energy storage, and power-to-gas (P2G) technology is a recent solution to this problem. In this research work, a novel biomass-based power plant is proposed, this specific type of biomass is composed of industrial wood chips and wheat straw chopped wood with a 3.48:1 mass ratio and 19 wt% moisture. Detailed energy, exergy, and exergoeconomic analyses are performed for each component, considering various ambient and system conditions. This power plant is also equipped with a carbon capture and storage system, by which combustion's carbon dioxide is separated, and a power-to-gas energy storage system, by which hydrogen and oxygen gases are produced, allowing it to produce synthetic natural gas by the methanation process with various industrial applications and reduce carbon emissions. The energy and exergy analyses show that the overall energy efficiency and exergetic efficiency of the plant are 56.49 % and 35.48 %, respectively, which are highly acceptable and feasible. The combustion chamber is the primary location of exergy destruction, accounting for 52 % of the total exergy destruction in the cycles, followed by the methanation unit (15 %) and the turbine (12 %). Furthermore, the effect of modified ambient and manual operational parameters on the overall performance of the plant is analyzed, increasing the gas turbine inlet temperature improves the plant's energy efficiency to 57 %; but leads to a negative impact on its exergy efficiency (32 %), which manufacturing barriers make it difficult to increase beyond 1600 degrees C. Building the plant in a warmer geographic location barely impacts the energy efficiency; however, it may cause a decline as high as 1 % in the exergy efficiency.