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U.S. Department of Energy
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Load forecast error probability distribution and its effect on target reliability studies

Technical Report ·
OSTI ID:103266
;  [1]
  1. Southern Company Services, Birmingham, AL (United States)
The load forecast will not be correct. That much is known. The extent of the error is not known. It is also not known whether the load will ultimately be higher or lower than forecast. Weather will also not he normal. It will either be more or less severe than normal. There are two ways to incorporate the uncertainty into utility planning: use a judgement-based but somewhat arbitrarily chosen amount to increase the reserve margin to reflect the uncertainty or estimate the shape of the errors and abnormalities and treat the distribution rigorously in the evaluation of the appropriate reserve margin. The most recent study of the Southern Electric System`s (SES) target reserve margin treated the load forecast error and weather variation with the rigorous approach. The 15% target reserve margin could have been dropped to 7% if not for these two uncertainties. The load forecast error accounted for 2.5% of the reserve margin, normal weather variation 6%, and weather cycles another 0.5%. This paper describes the methods and results of this rigorous calculation of uncertainty in setting the target reserve margin.
Research Organization:
Electric Power Research Inst., Palo Alto, CA (United States); Pacific Consulting Services, Albany, CA (United States)
OSTI ID:
103266
Report Number(s):
EPRI-TR--105012; CONF-930969--
Country of Publication:
United States
Language:
English