One embodiment relates to a power plant having a large steam generator, which is equipped with hydrocarbon-fired burners and/or with a gas turbine and which has a water/steam circuit connected thereto, and comprising at least one device for generating a CO2-rich gas flow, wherein the electrical power output of the electricity-generating part, of the power plant to the electrical grid is subject to power regulation controlled, at the power grid side. Some embodiments relate to a flexible operating method for the power plant that is fired with hydrocarbon-containing fuel, which operating method permits in particular a rapid adaptation of the power plant output to the power demands from the grid.