From Base to Cycling Operation - Innovative Operational Concepts for CCPPs

摘要

The increasing market share of renewable energy and high fuel prices in Europe have changed the operational profile of combined cycle power plants (CCPPs) dramatically. Faced with fewer operating hours than expected in their original business plans, CCPPs now need to deal with operational scenarios ranging from volatile and less predictable operational phases to mid-term preservation or even mothballing of plants. With a decreasing level of generated megawatts, the utility will face the need to generate any remaining megawatts as efficiently as possible and to be available whenever the energy market is paying premium prices for generated energy or frequency control reserves. This paper will point out the optimization potential for an operating combined cycle fleet, addressing the new operational aspects with a special focus on startup and shutdown improvements. This includes hot starts after night stops as well as starts after longer offline periods and the possibility of keeping the steam cycle in a heated condition. The paper takes the Mainz Wiesbaden CCPP KW3 as a showcase example of a plant which has recently changed from base load to a cycling mode. Operational flexibility enhancements successfully implemented in the plant as well as the results of tests for future upgrades and further aspects under consideration will be presented in the second part of the paper.