An exemplary 10 MWth biomass-fuelled CHP plant equipped with a FICFB (Fast Internally Circulating Fluidised Bed) gasifier and a Jenbacher type 6 gas engine was simulated using Honeywell UniSim R400 to estimate the power and thermal outputs. The biomass gasification CHP plant was integrated with either a pre-combustion adsorptive capture process or a conventional post-combustion amine process to achieve carbon-negative power and heat generation. The practical maximum of carbon capture rate achievable with an adsorptive CO2 capture process applied to a syngas stream was 49% in overall while the amine process could boost the carbon capture rate up to 59%. However, it was found that the two-stage, two-bed PVSA (Pressure Vacuum Swing Adsorption) unit would have a clear advantage over the conventional amine processes in that the CHP plant integrated with the PVSA unit could achieve 1.7% points higher net electrical efficiency and 12.8% points higher net thermal efficiency than the CHP plant integrated with the amine process.