The energy transition has arrived on the construction site. Nibler GmbH Fernleitungsbau from Obersendling, which has been laying cables for postal, railway, energy suppliers and municipalities for 70 years, has just tried out how a construction project can be as green as possible, i.e. environmentally friendly. In the pilot project on Hanauer Straße near the Olympia shopping center in Moosach, four workers laid fiber optic cables for four weeks on behalf of euNetworks GmbH. Electronic excavators, sustainable diesel and recycled building materials were used. Interim conclusion after 580 meters of construction site: 4.3 tons less carbon dioxide emissions than on a conventional construction site and around eight percent more costs.
“In principle, customers are increasingly demanding that construction sites be sustainable and that the CO₂ footprint is taken into account,” says Max Müller from Nibler Corporate Communications. So the company, which employs around 720 people, made its first attempt. The work was done with an electronic mini-excavator, an electronic loader as well as an electric vibrating plate for soil compaction and an electric tamper, all of which were rental equipment from the Munich construction machinery manufacturer Wacker Neuson. Charging at a mobile charging station at lunchtime and after work could be easily integrated into the work processes, reports Müller. And the workers were very satisfied with the performance and volume of the electric vehicles.
According to his information, the crew drove to Hanauer Straße in an electric bus. The diesel for the two construction site vehicles was not diesel, but HVO100, obtained from certified residual and waste materials such as used frying fat as well as vegetable and cooking oils. According to the manufacturer, this guarantees a CO₂ reduction of 90 percent, says the press spokesman. Deutsche Bahn also uses HVO100.
Müller’s conclusion: “It is certainly possible to design construction sites sustainably, even in fiberglass construction.” With the cable protection pipes from the Wackersdorf manufacturer ZIS Spezialbaustoffe made from 100 percent recycled material, around two tons of CO₂ were saved, with the electrically operated construction equipment 1.1 tons and with the special diesel 1.2 tons.
A good four tons of carbon dioxide – according to the CO₂ calculator from the climate protection organization myclimate, that’s as much as a business class flight to New York and back or a round trip in a luxury limousine from Munich to the equator. For Germany as a whole, the Federal Environment Agency recorded emissions of a good 745 million tons of greenhouse gases in 2021. Almost 90 percent of it was CO₂.
The company attributes the higher price to the organizational effort
Max Müller attributes the fact that the green construction site for Nibler GmbH was eight percent more expensive than a conventional one to, among other things, the higher organizational effort that such a pilot project without well-established processes entails. Otherwise you just had to deal with the prices and price fluctuations for energy, machines and materials. Recycled cable protection tubes were sometimes even cheaper than normal ones. Fundamentally, however, “the question is always: Who bears the costs of sustainable work?”
Holger Seit from the press office of the State Association of Bavarian Building Guilds agrees. Society has to spend significantly more money on green building than before. However, Seit warns against focusing exclusively on the CO₂ footprint: “The individual environmental goals are not without contradictions.” For example, anyone who strives for a circular economy on the construction site must accept that recycled material cannot be completely free of pollutants. However, there are very strict limits for pollutants in civil engineering. Even those who value water protection can hardly work with recycled building materials. “A green construction site is based on compromises,” summarizes Seit. And: “It’s excellent if you try a lot.”