When market forces require fossil-fired power generation units to cycle rather than base-load, it is important to maximise the cost benefits accrued from shutting down during unprofitable periods of generation by minimising the plant damage and fuel costs associated with the subsequent unit start up. In addition to these operational factors, significant commercial penalties can also be incurred when unit start ups do not proceed according to plan and the generated MW output fails to match the submitted MW schedule. This paper will present results obtained from the application of a novel framework for optimising power generation unit start ups, in which the costs associated with unit start up are minimised through a combination of good planning and automated execution of the start up procedure. The key idea is that the start up plan is continuously evaluated based upon pressures and temperatures as the unit cools during the shutdown period and is therefore well matched for when the unit is required to begin the start up procedure. In the case of combined cycle gas turbine plants, weather forecast data are also incorporated in order to predict the MW output of the gas turbine units. Case studies will be presented from 500 MW and 660 MW coal-fired power generation units in the UK, and 350 MW and 700 MW combined cycle gas turbine power generation units in the US. These recent applications present two innovative features. The first one is a single continuously-variable plan that has been developed to deal with the common start up situations which follow overnight and weekend shutdowns. There is therefore no need for separate hot, warm and cold start procedures. The second innovation reported in the paper will deal with how the system relays the predicted start up profile to a remote trading room, thus allowing a trader to submit in the "day-ahead" market a MW schedule for the unit start up that can be followed with a high degree of certainty.
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