Life cycle assessment of flue gas emission reduction options for lignite based pilot thermal power plant

Due to the growing world economy, population growth, increasing industrialization and urbanization, demand for natural resources and energy are significantly increasing. Potential environmental impacts of lignite need to be reduced so that the use of lignite, one of the major local energy sources in Turkey, can be sustained and keep its reliable position among local supply of energy resources. In this study, environmental impact potentials were evaluated in six categories using GaBi Education software and CML 2001 impact assessment method to evaluate the life cycle impacts of the electricity generation phase of a lignite based pilot thermal power plant. Environmental impact potentials for 1 kWh electricity generation were determined; Global Warming Potential (GWP) as 1,81 kg CO2-equivalent, Acidification Potential (AP) as 3,98 g SO2 equivalent, Eutrophication Potential (EP) as 0,32 g phosphate equivalent, Abiotic Depletion Potential for fossil sources (ADPfossil) as 11,6 MJ, Human Toxicity Potential (HTP) as 30,2 g DCB-equivalent, Photochemical Ozone Creation Potential (POCP) as 0,18 g ethane-equivalent. The degrees of improvement in environmental performance for three potential solutions for reducing amount of SO2 emissions in the flue gas from the pilot thermal power plant were investigated. According to the results of system analysis via GaBi LCA software; Option 1 "reduction of the flue gas SO2 emission concentration by 50% by improving the flue gas desulphurization units" resulted in a reduction of 27% in the final AP and 24% in the FOOP categories. Option 2 "addition of dry sorbent injection process prior to flue gas desulphurization system" resulted in a reduction of 94% in AP, 22% in EP and 31% in POCP, 3% increase due to the use of sodium bicarbonate as dry sorbent in GWP. Option 3 "adoption of fluidized bed technology at the same capacity to the current capacity, replacing the existing critical pulverized coal combustion system ", resulted in a reduction of 23% ADP and 19% in GWP; 94% in AP, 2% in HTP and 36% in POCP. In order for lignite to maintain its position among future energy sources, it is vital to develop policies and programs so that lignite-based electricity producing companies will implement projects for adaptation of these potential environmental performance improvement actions.