Environmental impact evaluation of conventional fossil fuel production (oil and natural gas) and enhanced resource recovery with potential CO2 sequestration

Conventional oil and natural gas production were compared with two case studies of enhanced resource recovery along with the potential for CO2 sequestration applications. The first case study is a Norwegian enhanced oil recovery (EOR) project, and the second focuses on enhanced coal-bed methane (ECBM) recovery in Japan. Both cases or systems involved the recovery of CO2 gases from a coal-fired power plant, followed by compression, transportation, and final injection of the greenhouse gas into geological formations as a solution to mitigate global warming. A life-cycle assessment (LCA) method was applied to measure how each system, conventional as well as enhanced recovery methods, impacts the environment. The first set of results presented were the inventory of air emissions (CO, CO2, CH4, SOx, NOx, NH3, Pb, Hg, etc.), wastewater-containing acids and sulfides, and solid wastes released because of both fossil fuel production and energy usage from the power plant. The impact assessment results because of the accumulated pollutants from all of the systems were calculated for the following set of common impact measures: global warming potential, acidification, human toxicity, eutrophication, wastes, and resources. The final (combined) scores of the entire system were also generated. These final scores, which included the normalization and weighting steps, allowed for overall comparisons for verifying the final benefits or drawbacks of a system. For the proposed EOR project, the greatest two environmental benefits (total impacts prevented) were calculated to be -9.8 x 10(-2) and -9.7 x 10(-2). As for ECBM, the best scores were projected to be -1.0 x 10(-1) followed by -8.70 x 10(-2).