Withholding investments in energy only markets: can contracts make a difference?

Abstract

Although there are mechanisms to control market power in the spot market, withholding investments can still increase profits and hamper adequate capacity expansion. We examine the effect on investment of one suggested approach to reducing market power, contracting longer term. We construct a stylized model of an energy-only market where two firms, each specializing in one technology, invest in a first stage, contract part of their production in the second stage and sell the rest in the spot market in the third stage. We compare this model to one of an energy-only market having two stages, investment and a spot market. We find cases where the contracts change neither capacity nor peak prices, where the foreclosing effect of one player blocking the other from contracts markets increases investments and reduces prices, and where the opportunity to foreclose the market can incentivize one firm to lower its investment and increase its pricing power to the detriment of consumers. The model relies on the simplest possible assumptions of imperfect competition (subgame perfect equilibria with Cournot agents). We illustrate the different outcomes in a numerical example with two load steps (peak and off-peak) where we change one parameter, the height of the off-peak time segment. We find cases with increased and decreased capacity as well as no change in capacity. Since there is no general characterization of the consequences of contracts in this simple example, there can be no characterization in more complicated models that contain the market structures included here, and regulators or competition authorities cannot rely on contracts to induce sufficient capacity expansion by reducing market power. One other market mechanism that has been proposed to induce investment, a capacity auction with predetermined capacity requirements, is a potential alternative to limit market power that deserves further exploration to determine the extent to which it can provide an adequate incentive to invest in the presence of market power.