A novel exergy-based cost and carbon footprint allocation method in the multi-energy complementary system

Energy efficiency, economic cost and carbon emission of multi-energy complementary systems are three key indicators to sustainable development in the low-carbon background. This paper analyzes the coupling relationships between energy, cost, and carbon emission flows in a combined cooling, heating, and power (CCHP) system. The CCHP system consists of biomass gasification, co-firing internal combustion engine by product gas and natural gas, concentrated photovoltaic thermal solar collector, and absorption heat pump. A novel exergo-carbon method with exergo-economic analyses is proposed to determine the exergy cost and carbon footprint rate of each stream in the CCHP system, and the unit cost and carbon footprint of multiple products of electricity, cold energy and heat energy are obtained by the proposed method. The impacts of co-firing ratio and photovoltaic coverage ratio on energy and exergy efficiencies and cost and carbon footprint of products are analyzed. The sensitivity of biomass carbon footprint is performed to show its influences. The total cost of products including economic and carbon costs, is discussed to guide the carbon market's pricing strategies. Under the design conditions, the unit exergy cost of electricity, chilled water and hot water are 0.1094, 0.7659 and 0.466 $ (kWh exergy)−1, and their unit exergy carbon footprints are 0.3651, 3.9050, and 2.3780 kg CO2-eq (kWh exergy)−1, respectively.