A recursive cost model for optimal allocation of renewable energy resources

A general recursive cost model is developed, describing the expansion process in a renewable-based power system with discrete projects. The projects are, for instance, hydro, geothermal or wind assuming specific investment costs and capacities, which is a measure of “size”. The model is general in the sense that it assumes any nonlinear nondecreasing demand function and arbitrary costs or cost functions for each project. Previous results are expanded by defining Long range marginal and average cost concepts (LRMC and LRAC) and these are explicitly interlinked with the recursive expansion process. In addition, recursive expressions now include both costs and output. The LRMC and LRAC concepts are used in decision rules for recursively determining the optimal size or utilization of energy resources for each project, i.e. optimal sizing. In particular, previous results are expanded by the appropriate use of the LRMC and LRAC concepts to marginal sizing (Current Marginal Cost, CMC) for a general nonlinear demand. Finally a case study is demonstrated, using the model and concepts with actual cost and capacity data from the renewable-based Icelandic power system, with both linear and exponential demand.