Generation companies' security-constrained optimal bidding strategy in day-ahead pool-bilateral power markets: A Cournot-based model

Abstract

Restructured electricity markets may provide opportunities for producers to exercise market power, maintaining prices in excess of competitive levels. This paper proposes a model for generation companies' (GenCos') optimal bidding strategy in a day-ahead oligopoly power market. Cournot model is employed to obtain market equilibrium in which elasticity of demand, transmission security constraints, participants' market power and bilateral contracts are taken into consideration. In order to consider network constraints a multi-period framework is presented to simulate market clearing mechanism in which behaviours of market participants are modelled through piecewise block curves. Subsequently, impacts of bilateral contracts as well as transmission security constraints on participants' characteristics and market clearing prices are studied. A mixed-integer linear programming is employed to solve the problem. Finally a novel multi-objective model is presented for security constrained optimal bidding strategy of GenCos by introducing heuristic effective-supply curves. Consequently, capability of price-maker GenCos to exercise market power and altering market characteristics is shown and impact of bilateral contracts is investigated. A 9-bus IEEE test system is used to implement the simulations and demonstrate the effectiveness of the proposed model.