Uncertainty of optimal generation cost due to integration of renewable energy sources

Integration of non-dispatchable renewable power sources within a utility service area warrants possible revision of default cost optima obtained by conventional economic dispatch (ED). Uncertain shifts in the minimum cost may be expected due to variation of demand and generation, and convenient prior estimates of such changes would undoubtedly be of importance to utility operation and economics. This paper provides twofold analytical support in this context. First, it introduces a lower bound to the ED optima as decided by variations of demand and generation from renewable sources. Second, it provides a margin of uncertainty within which the ED optima is expected to occur, assuming variation of demand and renewable generation to be bounded. Relevant formulations are presented, and suitably justified by ED studies on a twenty-generator system.