The Combined Heat and Power Act has been in force since 1 April 2002 and serves to maintain, modernize and expand CHP plants through CHP surcharge payments. The amount of the time-limited supplementary payments is determined on the basis of the nominal heat output of a CHP plant and the staggering according to output classes. The law was amended in 2008 and 2012. The promotion of CHP plants was improved through flexible term models and a reduction in bureaucracy. A further amendment took place on January 1, 2016. Here, the focus of the surcharges was largely restricted to the area of feed-in to the public grid.