The transition of energy systems to meet net-zero targets for CO2 emissions will require increased integration of intermittent renewable energy. Thermal power plants with carbon capture and storage (CCS) will have the important role of providing affordable dispatchable low carbon capacity, maintaining security of supply and enabling the expansion of other low-carbon sources. Whilst the flexibility of power plants is relatively well characterised, the flexibility of the CO2 capture plant is not well understood, particularly in terms of the overall CO2 emissions, process dynamics, operatbility and the energy requirements. Pilot plant and demonstration studies provide valuable insight on the key characteristics and factors that impact process flexibility. This study investigates the impact of plant scale and key process factors on the performance of amine-based CO2 capture during flexible operation. These insights will be applied to a case study that investigates dynamic performance during the start-up and shut down of CO2 capture plants.