Abstract
The electricity price will influence the future growth and mix of generation capacity that will in turn influence the future electricity price, and therefore, it is important to understand how electricity price is formed as well as its short-term and long-term impacts on the economy. This paper describes evaluation of PJM day-ahead market bidding data and comparison of various electricity markets in terms of the market clearing price and volatility. The objective is to find critical factors and mechanisms determining the movements of electricity price. It was found that speculation by a small number of bidders can cause price spikes, that a Nash equilibrium may exist during a delayed response of the electricity price to a decline of the fuel price, and that the hydro generation with storage capability effectively stabilizes the electricity price.