The sharp rise of electricity prices across Germany in 2005, provoked dispute. The climb in prices was blamed, among other things, on the introduction of the European Union Greenhouse Gas Emission Trading Scheme (EU ETS). In Germany emissions allowances were allocated free of charge to all companies. However, the electricity producers decided to include the value of the allowances as opportunity costs when calculating their variable costs and when establishing prices for consumers. The survey deals with questions concerning the legal and economic legitimacy of this approach and how to avoid windfall profits for the electricity producers.