Improvement of operational efficiency based on fast startup plant concepts

摘要

The power generation sector is currently confronted with new challenges relating to theconservation of increasingly dwindling fuel reserves. At the same time we must reduce CO_2emissions in order to counteract global warming.This paper shows that power plant operating strategies in which plants are shut down duringperiods of low load demand, along with the optimization of plant startup procedures, are a keyto reducing CO_2 and to conserving resources.Driven by changes in customer requirements in the U.S., Siemens developed new startuptechnologies at the start of the new millennium which made it possible to significantlyincrease the number of starts for which a combined-cycle power plant is designed. We alsomanaged to optimize startup procedures to such an extent that a plant which has been shutdown overnight can now be back in operation on the grid at full load in less than 30 minutes.This startup technology improves grid support capabilities in cases where the temporary useof fossil-fired power plants becomes necessary at short notice due to natural failures ofrenewable energy sources (e.g. lack of wind or cloudy skies).Shorter startup times improve operational efficiency. Even in a power plant operated bytraditional methods this reduces fuel consumption during plant startup and consequently alsoCO_2 emissions.An operating concept which shuts down the plant when excessive capacity is available on thegrid offers far greater potential for savings however. Savings in operating costs resulting frompower plant shutdowns during the night and at the weekend significantly improve plantprofitability. Especially at night and at the weekend, revenue from electricity is very poor,well below actual operating costs, due to overcapacity on the grid. This means that the plant isoperating at a loss during these periods. Shutting down the plant minimizes these losses.