ABSTRACT
Increasingly, we ask the machines that generate our electric energy to change the amount of power they produce; the industry calls this cycling. The growing market penetration of variable renewable generators, such as wind, is causing existing generators to cycle in order to compensate for wind’s variability. For large generators, cycling means operating in a less effi cient way, leading to higher fuel costs and air emissions. It also means an increased risk of creep and fatigue damage, which leads to higher maintenance costs and more outages (Agan, Besuner, Grimsrud, & Lefton, 2008).
