Improvement of the profitability of CCS by heat utilisation in industrial and municipal applications

The purpose of this research was to find out the economic and efficiency benefits of applying carbon capture and storage in combined heat and power (CHP) production in comparison to solely power production applications. Utilization of low temperature process heat from capture plant, air separation unit or CO2 compression in district heating system and/or industrial solutions offers significant integration potential to increase overall efficiency and feasibility of CCS processes. Case examples include two studies, namely retrofitting of post combustion CCS and greenfield investment on new circulated fluidized bed (CFB) based CHP plant utilizing oxyfuel. The case studies are based on real and existing CHP plants and energy systems. The studied CFB option includes three designs for different fuel mixes, including biomass (bioCCS or BECCS), which lead to carbon sink ("negative emissions") on life cycle basis. This could be a significant benefit also in terms of acceptance of CCS. Carbon capture processes were modeled using Aspen Plus process modelling software and the results were used in VTT's economic toolkit (CC-SkynetT). Special attention was paid on sensitivity analysis, focusing on profitability with different prices of fuels, heat, electricity and CO2 emissions. The results showed that significant improvements can be achieved by CHP in plants utilizing CCS, especially if condensing mode operation of the plants is possible to achieve high peak load hours during low heat demand. By this, the decrease in plant net power output due to CCS can be partly compensated