„We produce energy on the Lichtwiese campus very efficiently and in an ecologically exemplary way – and we are even capable of meeting more stringent legal requirements in future.“
Primary energy factor
The primary energy factor tells us how much primary energy (energy that comes from natural, as yet unprocessed sources, for example petroleum, natural gas and coal) must be used to produce a certain quantity of usable final energy: the lower the factor, the more efficient and environment-friendly the energy input.
Distributed energy supply
Distributed energy supply means the energy is produced near the point where it is consumed. The simultaneous generation of electricity and heat, and cold as well (combined power and heat generation or combined power, heat and cold generation), enables attaining high energy utilization rates of as much as 90 percent. In addition, transmission losses caused by the transport of energy are reduced. Distributed energy supply additionally relieves the load on the interregional power grids. STEAG operates more than 200 such installations across Germany.
It all began in autumn 2013 with first exploratory talks between STEAG New Energies and ENTEGA following the EU-wide invitation to tender from TU Darmstadt. STEAG New Energies had installed the three natural gas CHP units on the Lichtwiese campus some 15 years earlier. It has since then operated them and has become known as a reliable partner. In order to tap further synergies and efficiency potentials, the two companies decided to participate in the tendering procedure as a consortium. Together they developed a concept that went well beyond the stated requirements and convinced TU Darmstadt in every single phase from prequalification to the ultimate conclusion of the contract. Specified in the call for tender was the construction of a new central energy plant with combined power, heat and cold generation and the construction of a new cooling network in order to meet the increased requirements for cooling energy in future with an efficient generation and distribution concept. In addition, the consortium offered to modernize two existing CHP units – and as a unique selling proposition, to connect the district heating system of TU Darmstadt to the Darmstadt-Nord district heating network operated by ENTEGA. The particular advantage of this setup: the heat for the ENTEGA network comes mostly from Darmstadt's refuse-fired cogeneration plant and features an extremely low primary energy factor (see explanation on the left). With the new supply concept, worked out under the direction of technical project manager Dr. Jürgen Schöler and Mike Barthel, TU Darmstadt will achieve overall a very low primary energy factor for its energy supply in future. This not only benefits the environment, but also pays off in economic terms for TU Darmstadt: in the event of future new-build projects and energy-saving rehabilitation measures to existing buildings of TU Darmstadt, as much as ten percent of the construction costs can be saved. Background: For every building the German Energy Saving Ordinance specifies a maximum permissible annual primary energy requirement – and the specified values constantly are being tightened. If the primary energy factor of a building's energy supply is low, requirements are eased for energy-saving measures to be applied to building shell and building management systems. "This unique concept only was made possible by the good interdisciplinary cooperation both within the STEAG New Energies team and in the cooperation with ENTEGA," Ralf Cavelius explains.