The strategic Investment involves expenditure decisions for technologies as well as short term operational decisions under the fixed set of technology capacities committed in the initial investments. The operational decisions are typically made in response to the actual realizations of uncertain external parameters. The model for such strategy usually takes the form of the bi-level problem in which some of the constraints is itself an optimization problem in addition to the global optimization objective for the long-term planning. An effective way for handling the lower-level optimization in the bi-level problem is what is known as MPEC (mathematical Programs with Equilibrium Constraints) approach. The MPEC modelling transforms the lower-level optimization into a set of equalities of the Kuhn-Tucker optimality condition. This paper looks into the equilibrium mix of generation technologies in the liberalized electricity market.