The Green Bow goes for maximum reduction of CO2 emissions

Hard on the road to a zero-emission construction site

"It's not there yet: zero emission. But we are already going for maximum reduction of CO2 emissions on the construction site." Speaking are Stefan van der Voorn, contract manager for Rijkswaterstaat, and Sjoerd Gijezen, CSR manager for construction consortium De Groene Boog, which includes the companies Besix, Dura Vermeer, Van Oord, TBI (Mobilis, Croonwolter&dros), Rebel and John Laing.

De Groene Boog is realizing the A16 Rotterdam project on behalf of Rijkswaterstaat. The A16 Rotterdam will be an 11 kilometer long energy-neutral national highway between the A16/A20 at Terbregseplein and the A13 at Rotterdam The Hague Airport. The new connection will ensure that traffic on the A13, A20 and surrounding local roads will soon be able to travel more smoothly and will contribute to improved mobility, accessibility and livability of the region. Together they talk about the green measures taken on the project.

Measures in a nutshell

Gijezen takes us through all the methods being applied to drastically reduce CO2 emissions: "What is making a huge impact is the large-scale application of HVO fuel, good for 90% CO2 reduction compared to diesel. HVO is extracted from food industry residues and can replace diesel 1 to 1. We have also commissioned a number of heavy (>20 tons) electric excavators. We also use the e-CO2tainer, a hybrid generator that contains both batteries and a clean generator. It can be used stand-alone or hooked up to the grid to handle peaks.

The e-CO2tainer jumps on only when needed, unlike traditional diesel generators, which are running all day."

On-site power supply

That is the underlying question that had to be answered. Van der Voorn: "Do you bring the charger to the machine or the battery to the charger?" Gijezen: "An electric crawler excavator is not made to travel long distances efficiently. Ideally, then, you bring the battery pack to the machine." Van der Voorn adds that the best way of working was considered for each location. "That is a continuous search, accepting that these kinds of issues require pioneering work. Gijezen: "There are many factors involved in answering that question per situation. What can be supplied by the grid? What capacity does construction and electrical equipment require? And in what locations is it physically possible and worthwhile to make charging facilities?"

A perfect learning experience

There is a lot of talk in infra about alternative, clean power sources to get and keep the equipment rolling. This is the first time on a project of this size that maximum CO2 reduction has been looked at so intensively by really scrutinizing everything when it comes to power. Gijezen therefore sees De Groene Boog's working method as a perfect learning experience for future works.

"We generate a blueprint that is useful to everyone. Why keep reinventing the wheel?" A salient detail is that this green way of working was not in the tender. Van der Voorn: "De Groene Boog organized its own theme tables in response to the overarching request from Rijkswaterstaat to be emission-free by 2030. From those theme tables, together with suppliers of green technology, we looked at where we could already give substance to Rijkswaterstaat's green ambitions in this project."

More than promise fulfillment

The Green Bow wants to go a step further, beyond just fulfilling Tender promises: "We want to excel. The Green Arch has established an EMVU fund (the U stands for implementation) and offered it to the Department of Public Works. EUR 3 million is available to pay for sustainable measures from. A good incentive, then. But in the end, how to proceed? The theme tables provided many insights and ideas."

By sitting down with Rijkswaterstaat, experts and external parties, so many applicable measures emerged that, according to Gijezen, the EUR 3 million is not enough. For that reason, additional support was requested from the ministry. In June 2020, several proposals were submitted for that purpose, including the electric equipment. In September 2020, this contribution was allocated. Van der Voorn notes that due to good preparation, a very concrete proposal could be submitted. "In 2021 we went for a second round, that contribution was also awarded."

Learning process with necessary sacrifices

Gijezen sees it as a challenge to keep everyone "on board. "We run into some bumps, because we are treading the unbeaten path. But ... you learn mostly from the things that don't go smoothly. Then the trick is to keep motivating everyone so that we still reach the finish line together every time." According to Van der Voorn, that requires effort in addition to a willingness to learn.    

"We are sticking our necks out in several areas," he says. "The mindset has to be right, the noses have to be in the same direction. That requires a lot of persuasion from The Green Arch and decisiveness from Rijkswaterstaat. We know that what is being done now is a catalyst for future projects. That is why it is so important that everyone participates and continues to participate. We show that it can be done and that has a flywheel function. Realistically, we are far from being there yet, but we are paving the way to 'better and better'."

In conclusion, Gijezen says, "We see where we need to go. To achieve a goal over time, the front-runners need to be encouraged now. We have to realize that what we do now will be a requirement in 2030. And that's not that far away."