Research On The Determination Of The Concession Period Of BOT+EPC Project Nnder Nncertainties

In recent years, the infrastructure of our country began to rise a new mode-the BOT+EPC, especially highway projects. Some of the early completion of the project which use this mode has obtained good achievement, this new mode gradually showing peculiar advantages and in the future infrastructure of our country will be more widely adopt this mode. In the concession contract of BOT+EPC project the most critical content should be the concession period, the key of the BOT+EPC project’s success is focused by length of the concession period which determines the company recover costs and benefit, meanwhile, determines the risk-sharing and how prorate the interests between the govenment and the company,so it is the core issue which participants concerned.In the survey of some BOT+EPC project, there are two ways to decision concession period,one is reference the similar cases,the other is adopted by the state for 30 years,but such ways is not follow logic science and ridiculous,which is harmful public interest, this paper is focus on suggestion what is applicatively reckon concession period in BOT+EPC, to provide theoretical support for the decisions of subsequent projects, reducing the failure rate.A number of factors affect the concession period of BOT+EPC project, this paper have discriminated the key factors, and further focused on the uncertain factors which mainly include of the construction period, investment, traffic, prices and maintenance costs. The project net present cost to be uncertainty because uncertain factors effected.Use Monte Carlo simulate method is applied to calculate the NPV of certain confidence level, and account the NPVR that both participations can accept to get reasonable concession period range. Then building "a cake cutting model" of game theory which applied to calculates a reasonable concession period with antidromic Solving Method.Taking into account the forecast error may occur in the actual operation, this paper proposed that when project is operating, if the NPVR exceeds the boundary conditions,the dynamic adjustment model is built for adjusting concession period with the target of scientific distribution of benefits scientific, making the projects which in operation period also can control the concession period.Follow the simple figure to demonstrate the calculation process of concession period in the BOT+EPC project. That process prove the viable and utility value of the model, and provide reference method for the decisions of concession period in subsequent BOT+EPC projects.