Where does Giessen stand in terms of the energy transition? The answer is provided by a current energy report from Stadtwerke Gießen. On 3 February, Matthias Funk, Technical Director of SWG, and city councillor Astrid Eibelshäuser presented the most important results and drew a positive balance.
The German government's targets are clear: by 2020, greenhouse gas emissions and primary energy demand are to be reduced and the proportion of renewable energies in electricity demand and total energy consumption is to increase. In its latest energy report, Stadtwerke Gießen (SWG) shows that the city of Gießen with its population of over 80,000 is well on the way to achieving these environmental targets.
Positive energy balance
The city has achieved significant successes in the development of greenhouse gas emissions, for example. In 2014, only 7.5 tonnes of climate-damaging greenhouse gases were emitted for every Giessen resident - that is 2.8 tonnes less than in 1990. "We have succeeded in reducing emissions by 27 per cent in this period," emphasises Matthias Funk, Technical Director of SWG. "We are very pleased that Giessen has such a good record and that the development over the past few years has been so positive. We are on the right track," says city councillor Astrid Eibelshäuser, summarising the results of the energy report.
Alongside the reduction in greenhouse gases, SWG has also significantly increased the share of renewable energies in electricity generation: in 2014, it was around 26 per cent. With this figure, the city of Giessen is already one of the pioneers in the transition to renewable energies.
Expansion of regional generation
The high proportion of self-generated electricity in the city is particularly noteworthy. This was over 47 per cent in 2014. Matthias Funk points out: "This increase is due in particular to the fact that we have steadily driven forward the heating network and climate-friendly combined heat and power (CHP) generation - i.e. the combined production of electricity and heat - in recent years." SWG already exclusively supplies so-called Giessen green electricity to private households and commercial enterprises - regardless of the tariff. SWG produces 40 per cent of this directly on site with the help of highly efficient CHP, while the remaining 60 per cent comes from TÜV-certified hydropower plants. SWG is aiming to increase the proportion of self-generated electricity for households and businesses to 50 per cent by 2020.
This increase in regional electricity and heat generation contributes to the fact that significantly fewer greenhouse gases are emitted in Giessen than when these energies are produced separately in conventional power plants and boiler systems. Matthias Funk illustrates the major effect of CHP and district heating in terms of the energy transition with figures on pollutant emissions: "In 1990, we were able to avoid 20130 tonnes of greenhouse gases through decentralised generation. By 2014, this figure had more than quadrupled to a total of 9,350 tonnes."
Electricity savings target achieved ahead of schedule
The significantly reduced electricity consumption in Giessen also fits in with the positive overall result of the energy report. While it was 5.3 megawatt hours (MWh) per inhabitant in the comparative year 2008, it was only 4.4 MWh in 2014. This represents a saving of around 17 per cent. By comparison, the German government's target for this period is just 10 per cent. The city of Giessen, businesses and all residents have therefore exceeded this target by as much as 70 per cent.
SWG focusses on renewable energy sources
The energy report also shows that Giessen residents are consuming less and less primary energy - natural gas, heating oil or petrol - per capita. While this figure was still 37.8 MWh in 2008, it fell to 33.6 MWh in 2014.
"Eleven per cent savings in just six years - that's an exceptionally good result," summarises Matthias Funk. The reduced electricity consumption in the city and the particularly low primary energy factor have had a major influence on this development. This stands for the ratio of primary energy used to final energy supplied. In 2014, the primary energy factor in Giessen's district heating network was just 0.36. By comparison, a conventional natural gas boiler has a primary energy factor of 1.1, which is significantly higher.
This figure can be explained primarily by the widespread use of combined heat and power generation in conjunction with a well-developed district heating network. The factor of renewable energy sources also plays a decisive role. Stadtwerke Gießen has gradually reduced the proportion of fossil fuels used in favour of climate-neutral fuels. "We now only generate 36 per cent of our district heating from fossil fuels. Several biomass plants and the thermal residue treatment and energy utilisation plant (TREA) have been added," explains Matthias Funk, adding: "The energy report shows that we are on the right track with this strategy." When SWG commissions its second TREA in 2017, the primary energy factor will fall significantly once again - to below 0.2. Giessen will then be among the absolute leaders in Germany.
Continuing the expansion strategy
Giessen compares very favourably with other cities, as the energy report shows. "We now need to continue on the path we have taken and supplement our successful strategy with new innovative approaches," explains Matthias Funk.
The city, SWG and citizens will continue to work together to drive forward the energy transition. "Together, we can show that the ambitious targets set by the German government can be achieved. If everyone pulls together, we will succeed."