How marginal is lignite? Two simple approaches to determine price-setting technologies in power markets

How much carbon is in the price of power? The answer to this question determines many economic consequences of climate policies, i.e. in terms of costs for downstream industries. It requires, however, to first identify the cost impact of carbon pricing on the price-setting entity on the power market. Economic theory tells us that power prices are determined by the cost of the marginal plant. We propose two simple approaches to conclude on marginal technologies in electricity wholesale from public data. Both approaches are complementary, easy to implement, and based upon assumptions which are commonly used in more complex energy system models. We exemplify their use with a policy example on the compensation for indirect emission costs from the EU Emissions Trading Scheme. We find that the current policy design severely overweighs CO2 emissions from lignite power plants in the Central Western European power market, which may lead to overcompensation of industrial power users and therefore to a distortion with regard to the policy’s stated goal.