was a pilot project in the field of thermal utilisation of biomass. Due to the model and pilot character of the power plant, the project received subsidies from the federal and state governments through their respective ministries of food, agriculture and forestry in the form of a conditionally repayable investment grant. Subsidies were returned to agriculture and forestry under a contract that regulated the procurement of fuel from agriculture and forestry.

The Altenstadt combined heat and power plant (CHP) was the first pilot project of that size in Germany exclusively for the purpose of energy production.

The innovative feature was that various biomass fuels were burnt in a fluidised bed combustor. A thermal input of 35 MW was achieved, of which a maximum of 11.34 MW could be converted into electric power.

SIEMENS KWU was the general contractor that erected the plant. The project was launched on 15 September 1997. The plant has been in operation since August 1999. In the years 2005 to 2006, the power plant was optimised by making some conversions that increased the heat input to 40.4 MW.