For calculating life cycle cost of an any dg plants you can use HOMER or hybrid 2 developed by NREL

Hi, we have studied this question in our papers, please see 

http://arxiv.org/ftp/arxiv/papers/1206/1206.6808.pdf

http://ijeee.iust.ac.ir/article-1-740-en.pdf

Usually, conventional generators are represented by the two-state model, while the wind farms are represented by multi-state models according to the statistical nature of the wind speed. You then need to construct the COPT for each group of generators, then to merge them using the state enumeration method. You may refer to the following chapter,

https://www.researchgate.net/publication/307585524_Wind_Energy_Conversion_Systems_Reliability_Perspective?_sg=jQ-_gPyNlCDeNMtdFPVqCzT-mMnKKOkUMfAqLPQwgonO8bBRj1AyjXaEOLZzrU1tQicyGDKJt-1kEY_GZhHmeofagCFERgkI07gJq2QR.UOIQ5y6Dz9cfE2-9_qqZpwTcEjSOQgmbL8zRK27sE9flgLT2yaLAdYigdFiDd_yEMIOGcJ6UUNXMKSQpuzEFbA