Production costing models are widely used in the electric power indust
ry for the purpose of generation capacity expansion planning, fuel man
agement, and operational planning. These models account for the load v
ariation over time and generator outages. A widely used model, due to
Baleriaux and Booth, yields a prediction of the expected production co
sts and is based on the load duration curve and forced outage rate of
the generating units. This paper highlights the fact that, in order to
obtain a more detailed characterization of the probability distributi
on of production costs beyond the expected value, a model involving th
e stochastic processes underlying the generator outages is necessary.
A stochastic model is considered as an enhancement to the traditional
Baleriaux model. It is shown that Monte Carlo simulation can be routin
ely used on the enhanced model to provide answers concerning the distr
ibution of production costs. Monte Carlo methods avoid the problems as
sociated with the complexity of the analytical methods. Numerical exam
ples are given using the enhanced model where load is considered to be
either a deterministic or stochastic time-varying function. An exampl
e is given using decision analysis where a possible use of the more de
tailed information on the probability distribution of production costs
in generation system planning is illustrated.