Beginning next year, in 2022, all Mercedes-Benz car and van plants are scheduled to be CO2-neutral in their production operations. In order to achieve this goal, energy consumption has to be as low as possible and energy efficiency as high as possible. At the Mercedes-Benz plant in Hamburg, a company-wide project team is looking at ways to reduce energy use. It is doing this with a clear strategy, great creativity and a lot of passion.
If you ask Walter Gehrke and Rene Steinhagen if they have a vision of how production should look like in the future, they will give you the same answer: The energy supply for manufacturing will have to become just as important as the quality of the products. “Energy supply is a competitive advantage,” says Gehrke, who is responsible for the energy supply of the Hamburg plant. He and his colleague Rene Steinhagen, who is responsible for facility planning, have been working at the plant for almost three decades. They have been involved in sustainability projects for a long time now — not only at the plant, but also as ambassadors in the surrounding area and in the Hamburg industrial association. “Sustainability and environmental protection have been firmly embedded in our plant for many years and are part of our identity,” relates Gehrke, who also mentions the plant’s close cooperation with the German Nature And Biodiversity Conservation Union (NABU) as well as its many green areas, biodiversity projects and certified environmental management system.
However, efficiency is not only an important concern for finished products but also during the production process. In order to reduce energy and water consumption as well as its amount of waste, the Hamburg plant is making its processes more and more efficient, networked and environmentally compatible. Here, the plant is supported by the energy experts from Siemens Smart Infrastructure.
Cooperation since 1993
The collaboration with Siemens in Hamburg goes back to the early 1990s, when a central building control system was installed at the plant. This system supplies crucial data for making the energy flows transparent. “The building control system enabled us to identify the main energy consumers at the plant,” says Steinhagen. “We can use the system to operate all the machinery and measure and evaluate parameters such as energy consumption, temperature and fault messages. The system currently encompasses more than 1,400 energy meters. Naturally, this level of transparency provided us with the perfect basis to go a step further.”
This next step was initiated in 2016, when the team headed by Gehrke and Steinhagen worked together with the energy experts from Siemens to analyse all the energy consumption at the plant, make load profile assessments and determine potential savings. “We investigated each production hall and then made a rough analysis. Measures were then derived from these analyses for each hall,” recalls Gehrke. “We looked at how much we could reduce the consumption of natural gas, water and electricity, as well as the emissions of CO₂. Then, we compared the results to the costs of a conversion. In the end, we chose seven measures for boosting energy efficiency at the Hamburg plant.”
The conversion began at the plant at the beginning of June 2021. The measures include the installation of various energy-efficient ventilation and cooling systems that can be used precisely as needed. “Most of the energy efficiency measures involve taking a close look at the actual requirements and then regulating or automating the systems concerned as needed. This ensures that only the actual demand is covered, but not more. It’s an important step in the responsible use of resources,” says Christoph Lauterbach from Siemens, where he is responsible for the sale of energy efficiency solutions to Mercedes-Benz plants throughout Germany. “Let’s take, for example, a cooling compartment that is needed for cathodic dip painting. For this purpose, we used to employ an inefficiently powered fan that operated irrespective of the number of frames that had to be cooled. We were able to achieve big savings by combining needs-based control of this ventilation system — on the basis of the actual number of frames — with energy-efficient drive systems,” says Lauterbach.
In addition to the analysis of the building control system, the measures focused on the extensive involvement of the machine operators. “Jointly designing the change process and sensitizing the colleagues was very important to us,” says Steinhagen about the team’s approach. “Nobody knows as much about the machines as an operator who has been working on them for years. This kind of change only works in cooperation.”
Improving the life cycle assessment and the balance sheet
The plant in Hamburg has been working on optimizing its energy supply for many years. This is demonstrated in many measures that have already been implemented — not least regarding the lighting. Dana Peper is an engineer and the project head for the energy efficiency partnership at Siemens. According to her, there is still a lot of room for improvement. “We see the greatest potential at the interfaces between the infrastructure systems and production. The measures we chose focus on cutting the consumption of electricity and natural gas and thus also on reducing CO₂,” explains Peper. The measures improve not only the life cycle assessment but also the balance sheet. Saving electricity especially has a big financial impact. In some cases, the conversion costs can be recouped very quickly.
It is also crucial to monitor the measures that have been initiated. “Although it’s the last step in the process, it’s vital for the measures’ sustained, long-term success. Experts will continue to monitor all of the implemented measures for another two years. They want to know how the equipment behaves, whether the machine settings are correct, and if the systems are being properly operated. Even though this step is time-consuming, it shows whether the calculated savings are actually being achieved,” says Peper.
The first group of seven energy-efficiency measures at the Hamburg plant were only the beginning. Additional in-depth analyses are already being planned — not only in Hamburg but also at other Mercedes-Benz plants. “The Hamburg plant has ambitious energy targets and we will do everything we can to get a step closer to achieving them each day,” say Gehrke and Steinhagen.