The city of Giessen more than fulfils its role model function in terms of energy efficiency in the supply of heating and cooling to public buildings. This is possible thanks to the well-developed heating network and the numerous combined heat and power plants operated by Stadtwerke Gießen.
The example of Gießen proves this: With the right strategy and good cooperation between the city and the municipal energy supplier, the ambitious climate protection targets set by the German government can be achieved - and even ahead of schedule. In 2011, the combined heat and power plants (CHP plants) of Stadtwerke Gießen (SWG) already covered more than 50 per cent of the energy demand in the city's district heating network. The company thus met the requirements of the recently amended Renewable Energies Heat Act ahead of schedule. "In 2012, our CHP plants fed 65 per cent of the total heat required into the grid, while a further 15 per cent came from our biomass plants and the thermal residue treatment and energy utilisation plant, the TREA," summarises Matthias Funk, Head of Heat Supply at SWG.
The advantage of this plant park, which includes almost 40 small and large combined heat and power plants: a low "primary energy factor", which stands for the ratio of primary energy used to final energy supplied. A low primary energy factor characterises the environmentally friendly and efficient generation of electricity and heat. In Giessen's district heating network, it is currently around 0.41. By comparison, a conventional natural gas boiler is considerably higher at 1.1. "The excellent value in Giessen emphasises the benefits of CHP - the combined production of heat and electricity. As we are continuously expanding combined heat and power generation and constantly investing in modern systems, the local primary energy factor will continue to fall in the near future and stabilise at almost zero," promises Matthias Funk.
Good balance in favour of the climate
As a contracting partner of SWG, the city of Giessen supplies a large number of its buildings via the district heating network and thus benefits from climate-friendly energy. "We want to set a good example in our properties and are always looking for environmentally friendly energy solutions. In this respect, we have already achieved a great deal together with the municipal utilities," explains city councillor Astrid Eibelshäuser.
The figures show what the cooperation makes possible: compared to conventional heat and power generation, the municipality was able to reduce its CO2 emissions by around 1,300 tonnes in 2012 alone. "It's a stroke of luck for us to be working directly on site with a forward-looking energy expert like Stadtwerke - a company that has been investing in the district heating network and CHP for decades and is therefore pursuing a pioneering strategy," says a delighted Gerda Weigel-Greilich, Mayor of Giessen.
When it comes to climate protection, the consistent cooperation between the city and SWG also shows what is possible with the help of modern solutions in the new town hall. The building complex is not only characterised by an efficient heat supply, but also has an advanced air conditioning system - geothermal cooling in combination with absorption cooling. The latter is based on the principle of "cooling from heat". A so-called absorption chiller utilises the energy from the heating network to air-condition the public properties around Berliner Platz. "This technology is also used in our customer centre - as well as in some industrial companies in the city," explains Matthias Funk, pointing out: "Cost-effective, climate-friendly heating and cooling in the urban area - our integrated network and a large number of corresponding systems form the basis for all of this."
30.05.2014