In Saudi Arabia, last five years, Saudi Arabia has been aggressive to create the suitable environment and appropriate opportunities to activate and maximize the developmental role of the private sector. The privatization of the power generation sector gives the private sector promising investment opportunities and enhances its role in economic development. Cost Estimation model for 300 MW cogeneration plant was developed from inception phase until plant operation phase. BOOT contracting delivery system had been used on the subject cost model. The study shows that there are great rooms for money making ( IRR=27 %) by BOOT contractors in power generation field on the forthcoming period. The study, also, indicates that there is a big economical advantages for the investors due to low fuel gas cost on Saudi Arabia. Maximum detail on cost and cash flow with minimal service charges had been discussed on the subject book. As the subject study is pioneer study on Cogeneration Plant estimation using BOOT contracting system in Power sector on Saudi Arabia, It is published as a book