The current and predicted global massive dependency on fossil fuels calls for the exploration of new options to limit the future carbon dioxide (CO2) emissions. One such option that has been studied within the IEA Greenhouse Gas Implementing Agreement, is the capture and disposal of CO2 from combustion gases. Such options for Sweden have been examined in a system study financed by NUTEK (The Swedish National Board for Industrial and Technical Development).
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 can be captured from NGCC (natural gas combined cycle) 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. At approximately 300 MW power production capacities, the heat quantities produced (55–85 MW heat) are likely to be suitable for a reasonable number of the Swedish district heating networks.
CO2 neutral production and utilisation of methanol as an automative fuel for the transport sector integrated with production of electric power and district heat, 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. Examples of possible process concepts have been examined.
The resulting estimated total costs for capture, transport and disposal of CO2, are in the same order of magnitude as the current Swedish carbon dioxide tax (365 SEK/ton CO2). Plant owners have to be credited for the captured and disposed 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 todays uncertainties in the available basis for estimation of costs for large scale transport, injection and disposal of CO2 into aquifers.