Transport systems for ocean disposal of CO2 and their environmental effects

After removal from the power plant flue gas, the CO2 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 CO2 disposal, and they may pose an environmental and safety risk. Considering that a single 1000 MW bituminous coal-fired power plant equipped with CO2 removal system will deliver between 7.2-8.2E6 T/y of CO2 (228-260 kg/s), the only practical transport systems appear to be pipes and large tankers in which the CO2 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 CO2 is stored and transported as a pressurized liquid, there is a risk of rupture and release of large quantities of CO2. At concentrations in air above 10%, CO2 is an asphyxiant, and at smaller concentrations it causes nausea, vomiting, diarrhea and skin lesions. However the environmental impacts and safety hazards of CO2 transport systems can be minimized or altogether prevented with prudent management and exercise of precaution. (C) 1997 Elsevier Science Ltd.