DC Dredging talks about CO2 reduction and dilemma’s on sustainability at sea

Due to economic growth and a rising population, the demand for construction and infrastructure equally rises. These construction works require raw materials, such as sand and gravel, that are becoming more scarce on land. For this reason, more and more of the required raw materials are being sourced from the bottom of the sea. At the same time, offshore wind farms are being built at rapid speed to meet the demands for renewable power. This makes it more challenging to dig up the raw building materials from the sea, because the sea surfaces become crowded. DC Dreding, the Belgian dredging and sand extraction company, has the ambition to turn these dilemma’s into opportunities.

As a subsidiary company of the Belgian organization Groep De Cloedt, DC Dredging focuses on producing and offering raw construction materials such as sand, gravel and stone for the asphalt and concrete industry as well as railway construction and hydraulic engineering. A great number of raw materials that DC Dredging produces are being extracted from the sea. “We have five ships that extract sand and gravel from the sea. These raw materials are then transported to the main land”, says Dirk van Reijendam, who is hired by DC Dredging to further develop the organization. Van Reijendam is also responsible for the implementation of the CO2 Performance Ladder within the company.

“At DC Dredging, we noticed that we had less chance of being awarded a project in tenders where the CO2 Performance Ladder is being implemented as an award advantage. This triggered us to obtain a certificate.” The dredging company is momentarily working on obtaining its first certificate on the CO2 Performance Ladder at level 3. “Next to being awarded with projects and being able to register for various tenders, we realize that CO2 reduction is coupled with cost savings. That is why we expect the CO2 Performance Ladder to help us gain insights on the many possibilities to cut back carbon emissions resulting from our organization and projects.”

Dredging with less fuel

The fuel consumption of DC Dredging’s marine aggregate dredgers and ships result to the greatest number of carbon emissions. In order to save on fuel consumption and with it CO2 emissions, the dredger has developed a diesel electric aggregate dredger: the DC Orisant. This aggregate dredger is the first of its kind. The development of DC Orisant is made possible in collaboration with the Dutch firm Reimerswaal BV. “The diesel in this marine aggregate generates electricity which then drives the motors of the DC Orisant. Due to the generation of electricity, it requires less fuel than a marine aggregate dredger that solely runs on diesel”, Van Reijendam explains.

The marine aggregate dredger is provided with a power management system (PMS). This system ensures efficient consumption of power. “There are four generators and four electric motors on the ship. Depending on the power needed for the ship, the PMS will switch the generators on or off. By switching off one or two generators, there will be less fuel needed for the DC Orisant to sail compared to traditional marine aggregates. This enables us to save up on fuel consumption.”

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Next to the power management system, DC Dredging keeps track of the fuel consumption of its marine aggregates to sail efficiently. For this, the organization combines its sailing routes with insights on weather conditions and tides. “We strive to make the most of natural weather conditions to reduce the fuel consumption of our ships. If for example, there is an ebb current at sea, we will require less fuel, because we make use of the energy resulting from the current. This prevents us from wasting fuel.” Sustainable innovations such as the DC Orisant must contribute to the ambition of DC Dredging to cut back 5 percent of its carbon emissions in 2019 compared to 2017.

‘If there is no demand, there is no market’

Due to economic growth, the demand for more housing, offices and other construction works increases. “There were not enough houses built in the Netherlands for these past few years, which causes a shortage in the market. More housing must therefore be built. And what is required to build these houses? Raw materials”, says Van Reijendam. Acc