In order to achieve an improved or optimized operation mode of an “expanded drying section” of a paper machine—having the “actual” drying section, separated, if applicable, into pre-drying and post-drying sections with a size press located therebetween, a steam and condensate system, an exhaust air heat recovery system, a wet press and the white water—a model that includes the above system components is proposed, with which mass and energy balances for the system components as well as the specific energy consumption of the drying section are calculated, based on values for parameters relevant for the drying process.