Abstract
Competitive power markets from different countries exhibit a common market design, especially because of the nature of electricity (lack of storage, inelastic load, and strong seasonal effects on multiple time scales). For example, a majority of countries have created a spot market where electricity is traded hourly. The design of the spot markets reflected an ambition of providing strong incentives for efficient and least-cost production. Subsequently, the spot market price has been considered as a reference price for other existing electricity markets such as the contract market or the real-time market. However, empirical studies on electricity markets find some evidence of abnormally high markups. The literature on the electricity spot market mainly focuses on the producers' pricing decisions. The present thesis argues that quantity choices, both in terms of available as well as contracted quantities, are crucial for understanding market power in electricity markets.