Last month, the Delfland Water Board and the Municipality of The Hague signed a letter of intent to jointly investigate how treated wastewater can be used as a sustainable heat source. This involves water at approximately 20 degrees Celsius, which currently flows through enormous pipes to the Houtrust wastewater treatment plant and then into the North Sea. By harnessing this heat, as many as 20,000 households in The Hague could be heated without natural gas in the future.
The Hague wants to heat all its homes with clean energy and no longer with fossil fuels like natural gas. Aquathermy, heat from water, is a very useful clean heat source, available in many places in the city.
Arjen Kapteijns, Alderman for Energy Transition: ” I’m proud of this collaboration with the Water Board. The energy transition in The Hague requires all local sustainable resources. The opportunities for using the treated wastewater are enormous. So we’re eager to work with the Water Board to further explore where and how we can utilize this heat. “
One of the sources for aquathermy is the water purified at the Houtrust wastewater treatment plant (WWTP) of the Delfland Water Board. The purified water flows through pipes with a diameter of approximately 1.6 meters from Houtrust to the sea.
” Delfland believes it’s important to reduce the use of fossil fuels by switching to sustainable heat sources. The heat in the wastewater we treat is one such sustainable source. Delfland is eager to collaborate with regional partners, such as the municipality of The Hague, to explore how we can utilize this heat source. In this way, we can work together towards a climate-neutral region ,” says Hoogheemraad Nieske Dijkshoorn.
20,000 households
The heat from the wastewater can be used to heat homes and provide hot tap water. However, it still needs to be heated using heat pumps. In total, the wastewater contains enough heat to heat approximately 50,000 homes, but this requires a significant amount of space for the systems that need to further increase the water temperature. Therefore, the municipality and the Water Board anticipate heating for approximately 20,000 homes in The Hague.
Several issues still need to be investigated. The Water Board and the municipality will conduct this study together. Delfland owns the water treatment system. Among other things, they are investigating where the necessary infrastructure can be installed. This appears to be the biggest challenge of the project at the moment, as space is scarce in The Hague. A technical design is also being developed for the point in the pipeline where the heat can be extracted.
This will increasingly clarify which areas in The Hague are most suitable for aquathermal heating. The residents’ initiative “Warm in de Wijk” (Warm in the Neighborhood) from the Vruchtenbuurt neighborhood is interested in using the heat for a future district heating network. They are therefore closely involved in the research. This aquathermal source is expected to be available for use after 2030.
Text and images: Gemeente Den Haag
Translation to English: The Hague Online