Transport systems for ocean disposal of CO2 and their environmental effects

Abstract

Abstract After removal from the power plant flue gas, the CO 2 has to be transported from the power plant to the deep ocean. Because of the vast quantities that need to be transported, this is a formidable engineering task. The transport systems will add significantly to the cost of CO 2 disposal, and they may pose an environmental and safety risk. Considering that a single 1000 MW bituminous coal-fired power plant equipped with CO 2 removal system will deliver between 7.2–8.2E6 T/y of CO 2 (228–260 kg/s), the only practical transport systems appear to be pipes and large tankers in which the CO 2 is transported as a liquid. The environmental impact of offshore pipes will occur mainly during the construction phase. In USA territorial waters pipes need to be buried to a depth of 61 m. This means blasting and digging through sediments and reefs. After construction, the underwater habitat will be restored in a few years. Tanker transport requires major port and docking facilities, which could lead to perturbations of coastal habitat, and contamination due to leakages, spills and effluents. As CO 2 is stored and transported as a pressurized liquid, there is a risk of rupture and release of large quantities of CO 2 . At concentrations in air above 10%, CO 2 is an asphyxiant, and at smaller concentrations it causes nausea, vomiting, diarrhea and skin lesions. However the environmental impacts and safety hazards of CO 2 transport systems can be minimized or altogether prevented with prudent management and exercise of precaution.