STRABAG AG has finalised the restructuring of its soil treatment plant in Oberhausen. As part of this project, a partially electric construction site was evaluated under real operating conditions. The primary objective was to verify the technical performance of electrically powered construction machinery and to generate practical insights for future deployment.
Through the measures undertaken to redesign the soil treatment plant, STRABAG was able to increase the permissible input quantity from 120,000 tonnes to 350,000 tonnes per year. On the approximately 17,600 square metre site, extensive demolition, earthworks, civil engineering, and asphalt paving were carried out to create additional storage capacities. A key focus was on resource conservation: approximately 20,000 tonnes of surface paving and embankment structures were dismantled, processed, and reused as a recycled sub-base for the redesign of the areas. This illustrates a consistent implementation of the circular economy in construction.
As part of the new surface drainage system, approximately 128 metres of PVC pipelines were laid. Two precast concrete shafts, equipped with integrated lamella clarifiers for purifying surface water, were positioned using an electric mobile crane. Furthermore, an approximately 7,400 square metre treatment area was created. This was provided with a two-layer asphalt structure, resting on a base and frost protection layer made from recycled materials.
Trial of electric construction machinery under practical conditions
A significant aspect of the project involved the integration of eleven large electrically powered machines into the construction site operations. These included a 25-tonne excavator, a wheel loader, a mobile crane, and a road paver. To absorb peak loads and ensure a stable energy supply, a mobile battery storage unit with a capacity of 153 kWh was used, supplying the machines with green electricity. The test results show that heavy electric construction machinery can achieve a performance level comparable to conventional diesel-powered equipment.
The application of this technology led to reduced noise and direct pollutant emissions on the construction site. A purely theoretical saving of approximately 18,000 tonnes of CO2 was achieved. Although the acquisition costs for electric equipment are currently higher, these are partly offset by significantly lower operating and maintenance costs. In Oberhausen, energy costs were reduced by around 90 per cent. Challenges still exist in the availability of electric construction machinery in all sizes and the necessity of a powerful charging infrastructure at construction sites, which varies depending on the location.
Hybrid approach for efficiency and sustainability
To ensure swift project execution, STRABAG relied on a practical hybrid approach. Alongside the electric construction fleet, conventional machines were also used, which were operated entirely with the renewable fuel HVO100. Similarly, vehicles for logistics transport were refuelled with this diesel substitute. Robert Kucza, Sustainability Expert at STRABAG Directorate North Rhine-Westphalia, commented that the electric construction site demonstrates the practical viability of electromobility in construction and emphasised that real-world experience on the construction site is more convincing than theoretical considerations.
