Treatment of random generating unit forced outages
Derating Method: Discount each unit’s capacity by its forced outage rate (FOR).
For example, suppose in the previous example that unit #1’s (the 990 MW unit) FOR = 0.1 and unit #2’s (the 110 MW unit) FOR = 0.0
Then discount unit #1’s 990 MW capacity by 10% (its FOR expressed in %) to obtain 891 MW and leave #2’s capacity at 110 MW.
What’s wrong with doing this?