Focus on efficient use of energy
30.09.2025 – Stadtwerke Offenbach's subsidiary Offenbacher Verkehrs-Betriebe (OVB) has introduced an energy management system for its site at Hebestraße 14, which has been checked and certified by an external auditor from the Berlin-based company GUTcert.
"By introducing an energy management system, we are not only complying with new legal requirements, but it also helps us to further optimize our processes in terms of energy efficiency," explains Anja Georgi, Managing Director of Stadtwerke's Geschäftsfeld Mobilität. "Over the last five years, we have already reduced our total energy consumption from almost 19 gigawatt hours in 2020 to less than 11 gigawatt hours in 2024. We have achieved this largely by converting part of our fleet from diesel to electric drive: A diesel bus consumes an average of 500 kilowatt hours of energy to cover 100 kilometers. An e-bus only needs an average of 150 kilowatt hours on this route. In times of high energy prices, the efficient use of energy sources is relevant for environmental and climate protection reasons as well as for cost reasons."
Since this year, companies that consume more than 7.5 gigawatt hours of energy per year have been obliged to introduce an energy management system in accordance with DIN ESO 50.001:2018 or an environmental management system in accordance with EMAS. The certification process was carried out for the Stadtwerke mobility company for the first time this year and must be repeated annually in future.
The greatest savings potential lies in the electrification of the fleet
"In order to establish legal certainty, our energy management was reviewed and certified by an external auditor. The effectiveness of our energy-saving measures and the validity of our data collection and data analysis were checked," says Janine Mielzarek, Head of the Sustainability Competence Center at Stadtwerke. She is responsible for the introduction of the energy management system. "The greatest savings potential lies in the electrification of our bus fleet. However, we have also looked at all processes in administration, operations and the workshop from the perspective of energy efficiency, and the aim is to raise employee awareness of the issue through training, among other things." In 2024, the energy consumption of diesel buses accounted for around 62% of the total energy requirement, that of e-buses around 29%, electricity consumption in the properties themselves 4% and district heating and gas 3% each.
"The new energy management system enables OVB to transparently show where we need to make levers to make local transport in Offenbach not only more sustainable and climate-friendly in the future, but also more cost-efficient," says Mayor and Head of Mobility Sabine Groß. "The analysis of the data also clearly shows that we are on the right track with the conversion of the city bus fleet to electromobility."