Lawrence Berkeley National Laboratory

Life Cycle Assessment (LCA) should be used to assist carbon capture and sequestration (CCS) planners to reduce greenhouse gas (GHG) emissions and avoid unintended environmental trade-offs. LCA is an analytical framework for determining environmental impacts resulting from processes, products, and services. All life cycle stages are evaluated including raw material sourcing, processing, operation, maintenance, and component end-of-life, as well as intermediate stages such as transportation. In recent years a growing number of LCA studies have analyzed CCS systems. We reviewed 50+ LCA studies, and selected 11 studies that compared the environmental performance of 23 electric power plants with and without CCS. Here we summarize and interpret the findings of these studies. Regarding overall climate mitigation effectiveness of CCS, we distinguish between the capture percentage of carbon in the fuels, the net carbon dioxide (CO2) emission reduction, and the net GHG emission reduction. We also identify trade-offs between the climate benefits and the potential increased non-climate impacts of CCS. Emissions of non-CO2 flue gases such as NOx may increase due to the greater throughput of fuel, and toxicity issues may arise due to the use of monoethanolamine (MEA) capture solvent, resulting in ecological and human health impacts. We discuss areas where improvements in LCA data or methods are needed. The decision to implement CCS should be based on knowledge of the overall environmental impacts of the technologies, not just their carbon capture effectiveness. LCA will be an important tool in providing that knowledge.