Soort project:
Case study
Thema:
Real-world emission policy & strategy

Construction Site of Tomorrow

Status project

September 2021-September 2024 (completed)

In cooperation with

FIER Sustainable Mobility, J. Veldhuizen BV, Gebr. v.d. Brand en Van Oort BV and more

To achieve national emission and air quality targets, the construction site of the future must be clean and emission-free, with a significant role for electric equipment. In the DKTI project ‘Construction Site of Tomorrow,’ the practical use of electric machines was monitored for three years. This has provided valuable insights into deployability, energy consumption, emission savings, costs, and logistical challenges.

Working on the sustainable construction site

The construction sector still makes a significant contribution to the emission of nitrogen, CO₂, and particulate matter in the Netherlands. To achieve national nature and climate goals, construction sites must also become more sustainable. The Roadmap for Clean and Emission-Free Construction outlines how this transition to zero emissions can be realised. Currently, construction sites mainly use diesel-powered construction machines, which lead to significant local emissions.

Objectives

The replacement of diesel machines with electric equipment directly contributes to emission reduction on construction sites, but it raises many questions. How significant is the emission reduction in practice? What is the energy consumption, and does it vary by activity? Are electric machines suitable for all tasks, and how reliable are they? What logistical measures are needed for charging batteries?

In this project, TNO focused on deployability, energy consumption, and emission reduction, and examined performance in various use cases. The central question for the seven contractors and project partners was: are electric machines already a viable alternative today? Sharing practical experiences among the partners to learn from each other was an important objective.

Project approach

TNO monitored the energy consumption and practical emissions of six 17-ton mobile excavators and one 35-ton crawler excavator over three years at seven contractors. The machines, supplied by STAAD, were converted diesel variants, allowing for a realistic comparison between electric and diesel machines.

In collaboration with STAAD and one of their suppliers, it was investigated how the available data from the engine and batteries could be made available to TNO and how it should be interpreted. This provided insights into energy consumption, tasks, and battery performance, such as the number of operating hours, kWh consumed, and battery swaps performed. This data was then combined with work summaries from the contractors, allowing for performance analysis by activity type. It was examined whether energy consumption differs by activity type, such as forestry, rail maintenance, or demolition work.

Target groups

The results of this project are of interest to contractors, construction clients, and policymakers:

  • Contractors considering the use of electric equipment.
  • Planners and project developers looking to discover how to meet emission standards with electric equipment.
  • Clients, especially frontrunners such as RVB, ProRail, and Rijkswaterstaat, who have signed the Clean and Emission-Free Construction covenant.
  • Policymakers seeking insights into the practical use of electric construction machines.

Achieved results

Valuable data and insights

The electric machines were successfully deployed in this project, with a large amount of data collected over the project’s duration on the use of the machines in various types of work.

Deployability

The project demonstrates that electric excavators, even with limited battery capacity, can fully replace the use of diesel machines. In the first version of the machine, it was still necessary to swap one of the two smaller batteries on the machine about halfway through the workdays. With the (optional) upgrade and larger capacity, the machines could be used almost continuously without battery swaps.

Comparison of Diesel and Electric

Electric excavators prevent a significant amount of emissions. Annually, the monitored mobile crane saves approximately 21 tonnes of CO₂ and 18 kg of NOx, while the crawler crane saves 34 tonnes of CO₂ and 105 kg of NOx. This is equivalent to 300,000 km and 500,000 km of traffic emissions, respectively. The energy consumption per hour was also measured, showing that replacing a diesel machine with an electric one results in an electricity bill of about 4 kWh for every litre of diesel.

Contribution to confidence

The three-year trial has contributed to the project partners’ confidence in electric construction equipment. Due to their reliable deployability, even under harsh conditions and varying temperatures, contractors have experienced that electric machines are already a viable alternative on construction sites.

Recommendations

Specifically designed electric machines

Machines that are developed from the ground up for battery-electric use are expected to have lower energy consumption than converted diesel machines. Therefore, they are expected to perform even better in practice.

Charging infrastructure is essential

A heavy-duty power connection at the construction site is crucial to fully charge machines overnight (and possibly recharge them during the day). For long workdays, a 3x63A connection may even be insufficient for a single machine. By ensuring a heavier electrical connection early in the planning of new construction projects, charging problems can be avoided.

Why TNO

TNO has extensive experience in measuring the practical emissions of diesel vehicles on construction sites and has further expanded this knowledge in this project with practical experiences related to electric equipment.

For monitoring the deployment and emissions of construction equipment, TNO has developed data loggers, also suitable for entirely new electric machines with different signals. Thanks to TNO’s expertise in data logger development and data analysis, valuable insights can be obtained from the collected data.