Biomass: Technical and Environmental Alternative in the Thermoelectric Generation Process

This paper presents a technical (based on the exergy amount) and environmental analysis concerning an existing 50 MWe steam power plant located in the south of the Santa Catarina state - Brazil, designed to operate with pulverized coal and modified to operate in co-firing process with coal-biomass. In addition to the power plant, the study considered an extended boundary that involves the processes related to the obtaining, transportation, and handling of both coal and biomass. The exergy analysis was focused in the second law of thermodynamics, while the environmental analysis followed the Life Cycle Assessment (LCA) methodology, taking into account 1 MWh as functional unit and the global warming impact category, following the IPCC GWP index, over 100 years. For both cases (only coal and co-firing), the exergetic analysis indicated that the power plant is responsible for over 95 % of the exergy consumption. Results indicated that for the case of operating only with coal, 1,230 kg of CO2 e per MWh are emitted, whereas for operation in co-firing, with a share of 10% of biomass on energy basis, this amount changes to 1,103 kg CO2 per MWh.