Exergy-water-carbon-cost nexus of a biomass-syngas-fueled fuel cell system integrated with organic Rankine cycle

Abstract

Bioenergy is a water-intensive renewable energy and its upstream energy consumption and carbon emission during biomass planting, harvesting, collection, and transportation cannot be ignored. Biomass-based power systems necessarily have sustainable characteristics in energy, water, and carbon emissions. In this paper, a biomass-syngas-fueled solid oxide fuel cell system integrated gas turbine and organic Rankine cycle is designed. An exergy-based exergy-water-carbon-cost nexus method is developed to present the analysis of interactive relationships of the integrated system. The Sankey flows of cumulative exergy destruction, water footprint, and carbon footprint under the design working conditions are obtained and their corresponding intensities of the generated power are determined. The sensitivity analysis of biomass parameters, such as cumulative exergy, water footprint, and carbon footprint is implemented. The system exergy efficiency reaches 50.37 %. The accompanied cumulative exergy consumption to generate 1 kWh power exergy reaches 1.616 kWh. The water and carbon footprints of power are 63.59kg/kWh and 345.7 g CO₂-eq/kWh, respectively. Considering the exergy-water-carbon cost, exergy, water, and carbon account for 92.54 %, 0.63 %, and 6.83 % of total power cost, respectively.