Bidding behavior in sequential auctions for wholesale electricity : a case study of the NYISO

Abstract

This paper investigates the process by which bidders in the NYISO (New York Independent System Operator) market update their bids between the Day-ahead and Hour-ahead markets. Observed bids for the ten largest bidders over the years 2002- 2010 are used to investigate the extent to which observed bids into both the Day-ahead (DA) and Hour-ahead (HA) markets are consistent with joint profit maximization in the two markets. Theory about single period bidding behavior developed in the California spot electricity market (Wolak, 2003) and Texas electricity balancing market (Hortacsu and Puller, 2008) is extended to the two-period case specific to the NYISO market. While uncertainty comes from both the behavior of competing firms and additive uncertainty in demand, bidder behavior is broadly consistent with expected profit maximization against a stochastic piece of demand that is additively separable.