If you stand next to the Rhine River in Rotterdam and a cargo barge passes by, delivering containers from the port to inland customers, you’ll smell diesel–part of the polluting emissions from the vessel. But a new system could help easily retrofit the boats to run on clean electric power, and make new zero-emissions barges competitive with new diesel barges.

A Dutch company called Port-Liner is making both sleek electric, autonomous barges and a kit for retrofits. In each case, the barges use batteries packed inside 20-foot shipping containers, so they can easily be loaded on and off the boat. When the barge pulls into a shipping terminal, it can swap empty battery containers with some that are fully charged, or plug in to charge the batteries directly. The charging stations will use renewable energy, making the transportation emission-free.

Because charging with electricity is cheaper than diesel, and electric boats cost less to build and have fewer parts with less maintenance, the new boats–with the added benefit of self-driving tech–don’t cost more than traditional barges. Because they don’t need to have space for a giant diesel engine, they can also carry more cargo. For someone who already has a working diesel barge, and doesn’t yet need a new boat, the switch does require an investment, but because of changes in regulations, they’ll have to eventually do it.

“The retrofit will be necessary because we must reduce our pollution,” says Port-Liner CEO Ton van Meegen, who began working on the solution in the wake of the Paris climate agreement. To meet the Paris goal of limiting global warming, all industries will have to get to zero emissions in the next 32 years, including the 7,000-plus cargo barges running on diesel now in Europe.

The first new barges will begin use in the Netherlands and Belgium this year; the first version can carry 24 shipping containers, and a set of five of the barges can replace 23,000 trucks. A larger version will follow, with capacity for 270 containers, and then kits to do retrofits. “The complete package that we sell for retrofitting can be done by every marine installation yard,” says van Meegan.

For companies like Nike, which has a sustainably-designed distribution center in Belgium (complete with its own massive wind turbines, hybrid cranes, electric bikes for employees, and sheep instead of lawnmowers), barges are already a better choice than trucks, because they can carry more cargo and therefore have fewer emissions for each product. But shifting to the renewably-powered electric barges could eliminate those emissions.

Shipping products by canal and river is common in Europe. But van Meegan is also interested in potentially providing the technology elsewhere where barges aren’t in standard use at the moment but could be an alternative to trucks. “I’ve been to the Hudson River several times,” he says. “There’s nothing to see with container ships–it’s incredible.”