On the Impact of Forward Markets on Investments in Oligopolistic Markets with Reference to Electricity Part 2, Uncertain Demand

There is a general agreement since Allaz-Vila’s seminal contribution that forward contracts mitigate market power on the spot market. This result is widely quoted and elaborated in studies of restructured power markets where it is generally believed that generators tend to exploit the special characteristics of this industry in order to extract higher prices. Allaz-Vila established their result under the assumption that the production capacities of the players are infinite. This assumption might have applied to the power industry in the early days of restructuring but it no longer holds in today environment of tightening capacity. We show that the Allaz-Vila result no longer holds when capacities are endogenous and constraining generation. Specifically the future market can enhance or mitigate market power when capacities are endogenous and demand is unknown at the time of investment. This result complements Part 1 where the authors show that forward markets do not mitigate market power when capacities are endogenous and demand is known at the time of investment. It also complements other work by Grimm and Zoettl who show that forward markets systematically enhance market power in some symmetric capacity-constrained markets.