In April 2018, the STEAG employees in Gröditz put the new unit-type CHP plant into service.
STEAG New Energies (SNE) operates over 200 distributed plants throughout Germany – biomass and unit-type combined heat and power (CHP) plants across the country from the far north to the deep south. “We have been working successfully with or for local authorities and municipal utilities for decades,” says Thomas Billotet, who is responsible for the technology department within the SNE management. “This involves a wide variety of constellations: from services for design, construction, optimization or operation of a distributed plant to contracting models and joint ventures in the district heating supply sector. So we have every right to say that we have gained a host of experience.”
For example in Ilmenau. STEAG New Energies became involved in the Thuringian university town shortly after the fall of Communism and founded Ilmenauer Wärmeversorgung GmbH (IWV) together with the municipal authority in 1991. With the know-how of the STEAG engineers, IWV initially renovated and expanded the municipal district heating network and built a combined heat and power plant which went into operation in 1995. Increasing environmental awareness in municipal bodies and the pronounced innovative power of SNE led to the decision to build a biomass-fired CHP plant; the ground-breaking ceremony took place in 2003.
"We wanted to reduce our dependence on electricity from primary energy by using decentralized energy generation plants, and the optimal option for us was and is this biomass cogeneration plant,” says Gerd Michael Seeber, then and now Mayor of Ilmenau. After a construction period of only 16 months, Biomasse-Heizkraftwerk Ilmenau GmbH (BHI), a joint venture founded by STEAG New Energies and IWV, commissioned the biomass cogeneration plant. BHI invested 15 million euros in this plant, which since then has covered a quarter of the electricity consumption of the city of 26,000 inhabitants and half of the district heating energy and catapulted Ilmenau in Thuringia to the top of the cities with the highest use of renewable energies.
“The transition from large-scale utilities to local supply is a good one”
Two and a half hours to the east by car, there is another example of successful cooperation between a municipality and energy companies: STEAG New Energies has been supplying industrial customers, public buildings and private customers in Gröditz, Saxony, with district heating from the municipal heating plant via a 23 kilometer long pipeline network since 1993. Here, too, SNE engineers have been contributing their innovative knowledge ever since. In April of this year, the energy company commissioned a new unit-type combined heat and power plant that uses cogeneration to produce two megawatts of electricity and also heat. SNE invested around 2.7 million euros in this project and again the construction period was comparatively short at only twelve months. Here, too, local government is satisfied with the cooperation: “The transition from large-scale utilities to local supply is a good one,” says Mayor Jochen Reinicke.
“This conversion is a good example of how we can sensibly expand and renew the existing infrastructure,” explains Thomas Billotet. “As a result, both the plant and the utilization of the fuel – in this case natural gas – have become more efficient. The primary energy factor of the plant has dropped from 1.2 to 0.7, which saves energy resources. And the efficiency of the plant as a whole is remarkably high at 87 percent. This will make the heat supply from the Gröditz combined heat and power plant even more attractive for both existing and potential customers.”
STEAG is also in demand as a cooperation partner for municipalities in the west of Germany. In Mayen in the Rhineland-Palatinate, for example, where Fernwärmeversorgung Mayen, founded in 1998 by SNE, the local municipal utilities and the paper mill WEIG Karton, has become a model for sustainable energy use: Until the establishment of this joint venture, public and private buildings were heated from many decentralized systems based on heating oil and natural gas, but now industrial waste heat from cardboard production is almost exclusively used and the emission of climate-damaging carbon dioxide is therefore considerably reduced throughout the region.
“In this way, we have been able to reduce annual CO2 production by around 5,400 metric tons,” says Thomas Billotet. “In addition, we have expanded the pipeline network to around twelve kilometers, so that around 240 properties can now be supplied with environmentally friendly energy.”
Award for exemplary cooperation projects with local authorities
No wonder, then, that this unprecedented project has also met with a favorable response in politics: In 2014, the Rhineland-Palatinate Ministry of Economic Affairs awarded STEAG New Energies and the city of Mayen the tandem prize for exemplary cooperation projects between companies and municipalities in the context of the competition ‘Mittelstandsfreundliche Kommunen 2014’. STEAG has even been active in the neighboring federal state of Baden-Württemberg for much longer. In 1964, the energy company in Winnenden began supplying the Schelmenholz district with district heating, initially using a mobile energy center. Today, Fernwärme Winnenden GmbH & Co. KG, a joint venture of Stadtwerke Winnenden and SNE, has a connected load of 45 megawatts and, in addition to Schelmenholz, supplies the new development areas of Waiblinger Berg and Lange Weiden as well as parts of the city center. Overall, the annual heat production is sufficient for 3,500 single-family households.
And in Winnenden, too, the STEAG engineers proved how loyalty to the site and the will for constant renewal can be mutually beneficial: At the beginning of the 1990s, they converted a coal-fired heating plant into a plant that was fueled by gas and light heating oil. From 1997 onwards, the landfill gas from the nearby Eichholz landfill site was also used to generate energy. And in 2012, the heating plant was finally expanded into a combined heat and power plant that generates an electrical and a thermal output of two megawatts each by means of a natural gas powered gas engine.
“At this location, too, we have sustainably improved the energy efficiency of the supply,” explains Thomas Billotet. “The most recent conversion has improved the primary energy factor from 0.71 to 0.51. And the heat generated from renewables replaces conventional heat generation especially in the base load, with the result that the conventional boiler system which is still in place only has to be switched on when there is an increased heat demand. In this way, we have once again created an important building block for a safe and environmentally friendly energy supply.”