The inherent nature of electricity necessitates a permanent balance between generation and demand in electricity systems. This has obvious implications for the operation of CCS power plants in decarbonised electricity systems with inflexible nuclear and variable renewable supply. The low variable costs of nuclear and some intermittent renewable technology allow them to run as base-load generators and shift fossil fuel plants from base-load to midmerit plants. CCS power plants can be expected to increasingly operate in ways to balance variations, sometimes simultaneously, in the production of some intermittent renewable technologies and variations in electricity demand, resulting in more frequent ramping and start/stop cycles. As a result, they may also operate over a wide output range to maintain the quality and security of electricity supply by providing ancillary services, e.g. capacity and energy reserve, to the electricity network. This work characterises the operating envelope, the performance and the corresponding compressed CO2 flow of coal power plants for a range of loads, with or without voluntary by-pass of the capture unit. Optimised part-load operating strategies provide novel insights into the additional capabilities of CCS power plants specifically designed for enhanced operating flexibility.
- Post-combustion carbon capture