On Wednesday, 8 October 2025, the Delft District Heating Network reached an important milestone: for the first time, drilling took place beneath the city of Delft to develop a unique heat network serving the TU Delft campus and the city itself. This network will make use of clean, sustainable geothermal energy.
From E. du Perronlaan, two pipes — each 45 centimeters in diameter and 180 meters long — are being pulled beneath the Prinses Beatrixlaan and a water barrier. These pipes will carry sustainable geothermal heat to supply the campus, student housing, and several Delft neighborhoods. It’s an impressive operation, taking place 16 meters below ground, carried out by NetVerder and contractor Hanab, supported by eleven cranes guiding the pipes at the correct angle. Throughout the drilling, engineers continuously monitor the pressure in the borehole to ensure the structure remains safe and sustainable.
While most district heating networks are constructed in new residential areas, Delft’s network is being installed right through three existing, densely populated neighborhoods — beneath parking garages, alongside apartment buildings, shops, and allotment gardens. By drilling underneath the water barrier, the busy Prinses Beatrixlaan can remain open to traffic.
“This is truly a precision operation,” says Timo Idema, Managing Director of Stedin Group. “A city like Delft shows how complex the energy transition can be in practice. But with smart technology and strong collaboration with residents and organizations, we’re making it happen.”
Because of the inner-city location, the project requires special attention to its surroundings. The team has worked closely with local gardeners, residents, shopkeepers, and housing associations to ensure the operation proceeds safely and with minimal disruption.
“This underground drilling perfectly illustrates how Delft is shaping the energy transition: innovative, careful, and in close cooperation with the city,” says Alderman Zwart. “In such a complex environment, good coordination with residents and partners is essential.”
“That everyone — from residents to organizations — has given their approval is the result of clear communication and strong relationships with the community,” adds Timo Idema. “Without that cooperation, carrying out projects like this in an urban area would simply not be possible.”
The Delft District Heating Network is a collaboration between NetVerder, the Municipality of Delft, InWarmte, Geothermie Delft, and housing associations DUWO Student Housing, Stedelink, Vidomes, and Woonbron.
In this phase, 6,000 rental homes will be connected, with the goal of eventually supplying around 15,000 homes and businesses in total.
