Screening of Technologies for Carbon Capture from Offshore Gas Field Power Generation

In order to mitigate climate change, new solutions are being sought by energy companies to reduce CO2 emissions from offshore production facilities. Carbon Capture and Storage (CCS) may be a technically and economically viable alternative option compared to electrification of offshore facilities with power from shore or using offshore renewable power. However, decarbonizing offshore gas turbines using conventional post combustion CO2 capture technology is challenging due to the high flow rate of flue gas with low carbon content and space and weight constraints for retrofitting existing facilities. A high-level screening study was carried out to evaluate the techno-economic feasibility of several technologies to capture, compress and export the CO2 contained in the flue gas coming from two offshore operating aeroderivative gas turbines considering an existing natural gas production platform in the North Sea as case study. The following alternate concepts were compared to a base case developed using a generic mono ethanol amine-based CO2 post combustion capture process: Gas Turbine Exhaust Gas Recirculation; Gas Turbine Selective Exhaust Gas Recirculation (using either Membranes and/or Rotary Wheel Adsorption as CO2 selective transfer system in Parallel, Serie and Hybrid configurations); Membrane Contactor absorber; Floater or Gravity Based Structure with integrated carbon capture.The main conclusion drawn from this study is that most alternate cases lead to higher costs except from the membrane contactor which could generate substantial savings. The relative comparison between the different Selective Exhaust Gas Recirculation cases highlights a possibly optimum configuration with the parallel rotary adsorption based on Svante’s VeloxoThermTM technology. A different overall architecture is most likely required to make a significant step change and the possibility to integrate the carbon capture equipment within the hull of a Floater or GBS was identified as the most promising solution for lowering costs compared to the base case. Finally, each project is governed by site-specific conditions and this work is not intended to provide a generic solution for successfully implementing CCS on existing offshore facilities, however it may serve as a basis for further collaborative works including technology providers keeping in mind that a combination of several technologies will most likely be required to overcome the challenges due to the cost and complexity to implement offshore CO2 capture