Environmental evaluation of carbon capture and storage technology and large scale deployment scenarios

Carbon capture and storage (CCS) is the most viable option to reduce CO2 emissions from power plants while continuing the use of fossil fuels required to satisfy the increasing energy demand. However, CCS is an energy intensive process, and demands additional energy, chemicals and infrastructure. The capture processes may also have certain direct emissions to air (NH3, aldehydes, solvent vapor etc.) and generate solid wastes from degradation byproducts. A trade-off in environmental impacts is expected, and with the large-scale application of CCS needed to make any significant reduction in CO2 emissions, these potential trade-offs can become enormous in magnitude. Therefore a systematic process of evaluation of complete life cycle for all available CCS options and large-scale CCS deployment scenarios is needed. Life Cycle Assessment (LCA) methodology is well-established and best suited for such analysis. Methodology of hybrid life cycle assessment is used in this work and methodological developments are made to build-up simple approaches for evaluation of future CCS systems and scenarios. The thesis also extends the result presentation to more comprehensible damage indicators and evaluates control potentials for human health, ecosystem damage and resource depletion for the technology. The results of the study shows that the CCS systems achieve significant reduction in global warming impact but have multiple environmental trade-offs depending on the technology. These trade-offs are mainly due to energy penalty from capture process, infrastructure development and waste treatment processes. Damage assessment shows that the CCS systems greatly reduce human health damage and ecosystem damage by mitigating the climate change impact while increasing the resource consumption. Scenario assessment results show the clear advantage of global CCS integration scenarios over the Baseline scenario having significantly lower impact potential scores for all impact and damage categories from fossil-based electricity production. This thesis thus illustrates the assessment of a novel technology, its overall benefits and damages, development potentials and the implications of its large scale application.