The port says it is making efforts to change its business model.

“We try to work together with the polluters and eliminate them little by little,” says Oscar van Veen, director of innovation at the port of Rotterdam, speaking from a small boat in the port. He pauses, then corrects himself: “As quickly as possible, of course.”

But many of the port’s largest emitters respond to their headquarters in the United States or China.

Their loyalty lies in overseas boardrooms. If the rules in Rotterdam become too strict, they can simply move, as Shell moved its headquarters to the UK and Unilever abandoned Rotterdam entirely.

“The port of Rotterdam is a key player in this sustainable transition, but its sphere of influence is limited,” says Bettina Kampman of environmental consultancy CE Delft, which works for governments, companies and NGOs.

Even transitioning your own activities to reduce emissions comes with challenges.

“New developments need physical space. They can accelerate the development of energy infrastructure – the electricity needed to electrify processes. All of this is limited at the moment due to the lack of electrical cables,” says Kampman.

Emeritus Professor Harry Geerlings of Erasmus University Rotterdam has spent more than three decades studying sustainable transport and ports.

He is skeptical that a single port authority can drive a complete transition on its own. What is needed, he says, is a global level playing field, the kind of framework provided in Europe by the Emissions Trading System and previous rules on sulfur in marine fuels.

He points out how the EU’s sulfur limits changed behaviour: ships calling at European ports had to switch to cleaner fuels or install scrubbers to reduce pollution.

At first, China resisted, he says, but when its ships could no longer enter American and European ports without complying, it followed suit. “If you have the right incentives, you can change the behavior of these companies.”

But there are limits to what regional standards can do. Many ships now sail on dual-fuel systems, burning cleaner, lower-sulfur fuel when entering European waters, and then switching back to cheaper, high-sulfur heavy fuel oil once they are at sea.

Geerlings believes that the Rotterdam port authority really wants to change and is building the infrastructure for a smoother transition.

“But their greatest income is still tied to the fossil fuel industries,” he points out. “It’s not just an on or off switch. A port needs activity as a logistics node, otherwise it’s no longer a port. It’s a real dilemma.”