Nieuw Kwartier combines district heating, de-paving and sustainable mobility

In the Nieuw Kwartier in Leuven, cosily located between Naamsestraat, Parkstraat and Hendrik Consciencestraat, stylish middle-class houses in modernist architecture arose in the first half of the 20th century. Previously, sand was extracted from the existing sand pits at this location. Running straight through this neighbourhood is Constantin Meunierstraat: one of the widest streets in Leuven city centre, heavily used by cyclists but with little motorised traffic.

Soon the C. Meunierstraat is up for road works in order to renew the outdated sewer system.This makes the street ideal as a pilot location for linking various interventions to make the street climate-proof.The city of Leuven also wants to bundle the planned works as much as possible to minimise inconvenience to local residents.

Underground

The sewerage in Constantin Meunier Street needs to be renewed. To do so, the street has to be opened up, which tends to cause some necessary inconvenience to local residents. Today, the street has only one sewer pipe. This pipe drains both rainwater, which should replenish groundwater reserves, together with wastewater to the wastewater treatment plant. The unseparated water overloads the treatment plant, and prevents rain from permeating into the ground.

By disconnecting rain water drainage from the new sewer, the water can channel into the ground on site. Because of these impending works, the street was selected for the European Pilot Cities project, which examines which locations have great potential for district heating, and what is needed to make this happen. If the outcome of the feasibility study for a heat grid is positive, then, together with the sewerage works, a heat network could be installed which could eventually provide sustainable heat for 300 households.

Sustainably heating the city's entire building portfolio is one of the biggest climate challenges Leuven currently faces. Alongside individual heat pumps, collective solutions, such as heat networks, offer opportunities to move forward quickly. These heat networks transport hot water from one or more sources to multiple buildings, enabling collective heating (and cooling).

District heating is especially beneficial in densely built-up areas, which maximises every metre of pipeline. The system can extract heat from renewable sources such as the Dijle, sewage systems and the subsoil. From there, heat is distributed to buildings, allowing Leuven residents to sustainably heat their homes without having to invest in individual heat pumps.

The redevelopment of Constantin Meunier Street provides a lever to explore, and hopefully implement, collective heating for existing buildings. In addition, thanks to the JustNature project on nature-based solutions, a strong foundation has already been laid for resident participation, which is crucial to its success.

The City of Leuven is currently working with research and consultancy firm Sweco on a detailed technical and financial feasibility study for a heat network in C. Meunierstraat and surrounding streets. The results of this study will determine the next steps for the project. If the study yields positive results and confirms the feasibility of a heat grid in the Nieuw Kwartier, the neighbourhood will be further involved and the city will proceed to contact various potential stakeholders.

As the reconstruction of the streets is phased, over the period from 2026 to 2030, the same applies to the possible heat network. This will allow local residents to connect to it step by step.

Into the ground

Too little rainwater seeps into the ground in Flanders. The reason is the excessive paving: concrete and stone do not allow water to penetrate. This problem cuts both ways, because it exacerbates the effects of droughts and increases the risk of flooding. Because rainwater does not seep into the ground but is drained directly into rivers and the sea, our groundwater level is structurally too low. When there is heavy rainfall, this drainage system cannot cope with the influx, causing flooding because the water cannot drain away.

Although C. Meunier Street is not a floodsensitive area, rainwater that falls there flows away to lower-lying areas in Leuven, thus contributing to the problem. In other words, depaving makes sense everywhere. Through the European Horizon 2020 JUSTNature project, the city received financial leverage and extra capacity to set up an extensive civic participation process in the C. Meunierstraat that, together with local residents, is reshaping the street.

Since September 2023, a pilot layout can already be admired there, based on a design by Lama architects and Sweco, with residents' participation. The trial layout has since been evaluated and then expanded, to bring even more green space into the street and test out one-way traffic, to free up surface space. Currently, based on the lessons learned from the trial layout, a final design is being designed, which will be presented to the neighbourhood in early 2025.

Above ground

Along with the introduction of green spaces in the street, one-way traffic was also experimented with at the same time. This reduces traffic pressure, improves air quality and frees up space for green meeting places for the neighbourhood.

Circular design

The pilot layout was carried out using circular materials wherever possible. Reclaimed curb stones from other locations in the city were used to create planting beds. Old train sleepers were used as benches. Atelier Circuler built a pavilion and later also garden areas from reclaimed Leuven materials. Both the pavilion and the planting beds can be dismantled and reused in another location.

Breakthrough

Constantin Meunierstraat finds itself in a unique confluence of circumstances. By combining the planned reconstruction of the sewerage system with the ambitions of the Pilot Cities project on green heat and the JUSTNature project on nature-based solutions, as well as by throwing sustainable mobility in the mix, the city of Leuven is on its way to making the C. Meunierstraat a Leuven Climate Street.