The invention relates to a power plant for generating electrical energy, comprising: means for generating electrical energy from fossil fuel, biomass or biogas, means for extracting and saving carbon dioxide from flue gas generated in the power plant, characterized by an electrolysis apparatus for converting the stored carbon dioxide to other substances, a control apparatus for controlling the electrolysis apparatus, designed such that the control apparatus obtains current electricity price data and, when the electricity price falls below an electricity price threshold, causes the electrolysis apparatus to operate and, when the electricity price exceeds the electricity price threshold, shuts down the electrolysis apparatus.