Net 0 on the A16 at Rotterdam
In October 2025 we will be opening the A16 Rotterdam extension, an 11-km long motorway link on the northern fringes of Rotterdam from the Terbregseplein interchange to the A13 at Rotterdam The Hague Airport. The A16 Rotterdam, which includes the 2,2-km long Rottemeren Tunnel, will be the world's 1st net 0 motorway including a tunnel. How did we achieve that? Read on to find out.
The average tunnel consumes a good deal of energy. That might sound strange, but tunnels have dozens of systems, such as fans, emergency assistance boxes and lighting, that use lots of energy. Just consider lighting and safety systems, which run day and night. And yet, the A16 Rotterdam is the 1st net zero motorway (with a tunnel) in the world. How’s that possible?
Direct current
First, we need to talk about domestic appliances, such as your kettle or coffee percolator. They operate on direct current. But what comes out of the power outlet is alternating current. So domestic appliances are fitted with an adapter: this converts alternating current into direct current. Which is convenient, of course, but the process means that energy and heat are lost.
We've taken a smarter approach in this tunnel. Most systems, like cameras, loudspeakers and lighting, are fed with direct current. Wave goodbye to energy-wasting converters. In this way, we can save on both energy and materials: for instance, we had to lay fewer cables and cable trays!
But, there's more: the lighting. We need a lot of light at the start of the tunnel: this makes it easier to adjust to the transition from outside to inside, and vice versa. The asphalt here is reflective. And the tunnel walls there are also treated with a special covering. The result? The light at the tunnel portal reflects better, so the tunnel lighting doesn't have to shine as intensely. And the less intense the tunnel lighting, the less power is consumed.
Sustainable design
The design, too, was conceived with sustainability in mind. Many parts in the tunnel have been designed to be modular. That means that they are easier to maintain and replace. The tunnel cameras, for instance, have to be replaced over time. The good thing is they have many individual components that are easy to recycle. So when the time comes, they'll go to a company that can make them into new cameras.
Another factor in a sustainable tunnel is the need for sustainable maintenance. We consistently monitor energy consumption in all systems in this tunnel. If something suddenly starts consuming much more electricity than usual, we know something's wrong. That way we can respond quickly, before anything fails.
Generate your own energy
Of course, a net 0 policy is not just a matter of consuming less energy; you also need to generate your own energy. So, alongside the A16 Rotterdam there are 3 fields of solar panels: 1 at the start of the A16 Rotterdam, 1 at the junction of the A13 and the A16, and 1 halfway along the new section. A total of 5,000 solar panels can collect all the energy we need.
If we generate more energy than required on any given day, we can store the excess in batteries. This means that the electricity network doesn't get overloaded, and we can also use our own energy in overcast weather or during the night.