A data-driven analysis of supply bids in California ISO market: Price elasticity and impact of renewables

One month of supply bids in the California ISO day-ahead energy market are analyzed in this paper. A total of 1.5 million records of bid data are studied. The bids are studied based on their types and their distribution at different hours. The relationship between the market price and the offered supply capacity are investigated. A data-driven estimate is provided for the aggregated supply curve and accordingly the price elasticity of supply is identified for hours that price is highly inelastic. Importantly, this analysis shows the impact of the recent high capacity installations of renewable generation in the state of California on electricity price and price inelasticity. Finally, the undesirable consequences of price inelasticity, such as on creating price spikes and exercising market power, are discussed.