Despite the efforts of many governments and movements to phase-out/phase-down coal use in the Global North, global coal power generation capacity has expanded in the last decade. Coal will remain a dominant source for electricity production over the next two decades or more, especially in Southeast Asia and Africa. Therefore, decarbonisation of coal power generation is vital to meet global climate change mitigation goals. Carbon capture is central to least-cost pathways to net zero emissions.
In modern electricity systems with high levels of intermittent renewable power, conventional baseload power plants are increasingly required to operate flexibly with wider load range, faster ramping and frequent starts/stops while maintaining efficiency, equipment durability, environmental compliance and providing low-cost electricity. For existing conventional coal power plants, there are various options to improve their operational flexibility to meet the new challenges of modern power systems.
Depending on factors such as plant age, type, configuration, and the existing instrumentation and control (I&C) system used, there is a range of possibilities and measures to enhance flexibility from retrofitting certain plant components, making operational modifications, and implementing advanced I&C systems to revising plant operating procedures and staff training.
For power plants with integrated post-combustion carbon capture (PCC), the capture systems must follow the operational regimes of the host plant and achieve a high CO2 capture rate at the lowest cost. There is ongoing work on the operational flexibility of PCC systems. Measures that have been proposed and investigated include segregated solvent inventories, solvent storage systems and fast-starting steam cycle technologies.
This study reviews the technologies available to increase the operational flexibility of existing coal-fired power generating units and explores measures to flexibilise the operation of PCC systems that are integrated with coal power plants. The existing and emerging CO2 capture technologies for PCC of CO2 at coal power plants are reviewed.