Electricity producer offering strategies in day-ahead energy market with step-wise offers

This paper addresses the problem of the development of optimal offering strategies by electricity producers in day-ahead energy auctions with step-wise energy offer format. The producer energy offer optimization is formulated as a bi-level optimization problem, which is converted to a mathematical program with equilibrium constraints (MPEC). The producer MPEC is subsequently converted to a mixed integer linear program (MILP) using binary expansion of offer quantities and prices. The uncertainties under which the producer must develop his offering strategy are modeled. Test results on a small, ten-unit test system address the effect of the auction settlement rules (uniform or discriminatory pricing) as well as the producer's forward commitments on the producer strategic behavior in the day-ahead energy market.