A more sustainable Utrecht through Digital Doppelganger

More houses are needed, but at the same time we want to live in a greener environment. We want to live in a city that is easily accessible, but at the same time we value fresh air, and attractive, car-free pedestrian areas. We want shops to be well supplied, but do not want nuisance from heavy traffic. They are all wishes that seem to contradict each other. While all of them ultimately serve the same purpose: a city where people can live, work and relax happily. However, does creating more green space automatically mean less space for housing? And does good air quality necessarily go hand in hand with poorer accessibility? Or can it be done differently? The province of Utrecht and the HU University of Applied Sciences Utrecht are investigating this. HU students, researchers and collaboration partners are developing a digital twin of the city of Utrecht. In it, we map CO₂ and particulate emissions, heat stress and traffic flows of the city so that urban planners and stakeholders can search for optimal solutions. If you can demonstrate that an adaptation in the city will give an optimal result, support for the adaptation is quicker. Moreover, such an optimal adaptation can save a lot of inconvenience and money. 

The city of Utrecht's Digital Twin displays data from the city in 3D. You can see exactly at which buildings or squares there is heat stress; where in the city CO₂ emissions or particulate matter emissions are too high; but also where traffic congestion occurs. The relationship between these factors is included in the twin. In the digital twin, you can test scenarios. "So if you fix a recurring traffic jam, you also see what that does to particulate matter and CO₂ emissions," said Koen Smit, researcher at the HU University of Applied Sciences Utrecht. The digital twin helps governments, city planners and residents of a city to empathise with the impact of decisions on the city. "One of the things we are exploring in the digital twin is how to build housing as sustainably as possible, because then we can build more and that is needed because of the current housing shortage."

The new Cartesius neighbourhood is one such building project where sustainability is being explored via the digital twin. HU student Jippe Heijnen helped expand and link data and analyse transport flows at the Cartesius construction site. Jippe: "We incorporated a lot of relevant data from the environment into the digital twin and we compared two scenarios. On the one hand: what it would mean in terms of traffic congestion and CO₂ and particulate matter emissions if building materials were brought to the site by trucks - which is the current practice. On the other hand, we have pictured what it would mean if materials are brought to the construction site by electric boats. Indeed, Cartesius is close to the Amsterdam-Rhine Canal. Use of the waterway reduces high emissions. But also produces less traffic congestion. Indeed, there is still plenty of space on Dutch waterways. While highways bear a heavy load of traffic. A great opportunity, then. But you can also see in the twin where problems can arise: If you take our digital boat to the digital Cartesius, you will see that a large pipe blocks the waterway to Cartesius. You wouldn't have seen that in a run-through on paper. Because you now see the environment almost in real life, these kinds of practical consequences surface immediately. Another issue is: How do building elements come ashore? Should quays be constructed? Or should there be temporary platforms on the water? And where then? Even with questions like that, you can look at what is sensible in the digital twin."

The digital twin is not yet fully developed. HU researcher Koen Smit: "There are still all kinds of further developments possible. Both for the city of Utrecht and more broadly. For example, the twin is also useful for water management. You could test scenarios in which the water level rises. Or think about identifying solutions to electricity network problems. For example, installing wind turbines. With the twin, in the future residents may be able to experience whether a wind turbine will cause nuisance. If we want to do that, though, additional datasets need to be put into the digital twin, and links need to be explored." A city's digital twin also offers opportunities internationally. Rob Peters of the province of Utrecht: "We are leading the way in digital twinning of cities in the Netherlands. This is not surprising: in the Netherlands, we measure an awful lot. In many other countries, all this data is not available. So we are actually above average in coming up with solutions, based on this data. And in the twin, we can oversee the practical consequences. So that we can be sure that those solutions 'in real life' are also smart solutions."

• ICT Degree Programme (NL)
• Research group Meaningful Digital Innovation (NL)
• Research group Building future cities (NL)
• Province of Utrecht
• Cartesius Utrecht