In this paper, we set out to investigate the price and quantity fluctuations in Western Denmark, which took place during the winter season 2002-2003. It was a period, which exhibited critical supply conditions in the Nordic area due to a shortage of hydropower. On average, the market in Western Denmark helped to ease the situation by large net exports. However, a more detailed investigation reveals anomalies in market behaviour that do not fit well into this overall positive description of the situation. Several explanations of the anomalies are offered. These may work separately or act in concert. In particular, we look at: the exercise of market power and gaming of the dominant power generator; the role of the large capacity of volatile wind power; the role of the guaranteed fixed prices and the design and functioning of the special auction system of transmission capacity in the interface between Western Denmark and Germany. (c) 2005 Elsevier Ltd. All rights reserved.