Technology and cost options for capture and disposal of carbon dioxide from fossil fuel based energy production.: A system study.

Among several options to limit the future carbon dioxide (CO2) emissions, capture and disposal of CO2 from combustion gases has been studied within the IEA Greenhouse Gas Implementing Agreement. Such options for Sweden have been examined in a system study financed by NUTEK (The Swedish National Board for Industrial and Technical Development). Permeable geologic formations - saline aquifers - that should be suitable for disposal of CO2, exist in the South of Sweden - Denmark and in the Baltic Sea close to Lithuania. Based on commercially available technologies, CO2 could be captured from natural gas combined cycle, pulverised coal combustion and coal based IGCC (Integrated Gasification Combined Cycle) power plants. Most of the energy needed for the CO2 capture could then be recovered as district heating, thus maintaining the total energy efficiencies. CO2 neutral production and utilisation of methanol as an automotive fuel for the transport sector integrated with production of electric power and district hear, could be achieved with biomass combined with natural gas or coal as a raw material, An amount of CO2 corresponding to the carbon in the fossil fuel then has to be captured and disposed. Material and energy balances as well as costs have been estimated for examples of possible process concepts. Although pulp mill boilers are biomass based and consequently CO2 neutral, large amounts of CO2 are actually emitted to the atmosphere from combustion of black liquor and bark in several Swedish pulp mill boilers. Possibilities and costs for capturing and disposing CO2 from pulp mills have therefore been examined for model cases with a capacity of 1000 ton pulp/day. Plant owners have to be credited for the additional costs for capturing and disposing CO2 in order to make this option economically justifiable and interesting for them. It will be important for the total economy to find favourable combinations of energy conversion, CO2 capture and recovery, transport and disposal. There is also a need to reduce the current uncertainties in the available basis for estimation of costs for large scale transport, injection and disposal of CO2 into aquifers.