Mixoptim calculates the generation cost of a mixture of electricity sources, by means of a Monte Carlo simulation of the production output taking into account the fluctuations of the demand and the stochastic nature of the availability of the various power sources that compose the mix..

You can use the online version: http://app.mixoptim.org, or get the standalone versions (in Java or Fortran 90): mailto:bernard.bonin@cea.fr.