Start of construction of largest heat pump in the Netherlands

On Tuesday 5 July, the construction of the largest heat pump in the Netherlands was given the official go-ahead. The pump is part of an aquathermal installation that will be producing sustainable heat for approximately 20,000 households in the municipality of Utrecht and Nieuwegein; a major step forward in creating a fully sustainable heat network.

The heat pump will be located on the site of the Utrecht sewage treatment plant of De Stichtse Rijnlanden Water Board (HDSR). There, day-to-day management board members Constantijn Jansen op de Haar and Els Otterman of De Stichtse Rijnlanden, together with Cees de Haan and Manja Thiry of Eneco, gave the official go-ahead for construction today. If the construction progresses well, the installation will form a new sustainable heat source by the end of 2023.

Sustainable heat for approximately 20,000 homes
The heat pump will be built on the site of the sewage treatment plant in Utrecht. Every day, about 65 million litres of waste water are treated here. The waste water entering the treatment plant is relatively warm. With the arrival of the aquathermal installation, the heat will no longer flow away, but the temperature of the purified water will be used for the heat network. A heat exchanger and the heat pump will bring the heat network water to a high temperature of 75°C. This water will then be supplied to the heat network. Eneco is also constructing a buffer tank approximately 18 metres high and 18 metres wide to ensure that sufficient heat is available at all times. 

To connect the heat pump to the existing heat network, Eneco is also installing a new heat pipe of 600 metres in length. When completed, the installation will supply 583,000 GJ of heat to the district heating network each year. This will be sufficient to provide approximately 20,000 homes with sustainable heat, which corresponds to about 15% of the total heat demand of the district heating network of Utrecht and Nieuwegein.

The heat pump building itself will also generate energy, because it will be fitted with 177 solar panels, that together will provide 40,000 kWh of energy annually. This is equivalent to the energy consumption of 13 households.

Climate neutral 
Both the De Stichtse Rijnlanden Water Board and Eneco have the ambition to become climate neutral. The close cooperation of both partners in combining sewage treatment with the generation of heat creates a good new sustainable heat source. Thus, the partners are investing directly in making the district heating of the municipalities of Utrecht and Nieuwegein more sustainable. Municipalities that also have the ambition to operate in a climate neutral manner.

Els Otterman, board member of HDSR: “Aquathermal energy is a sustainable heat source with a lot of potential, without the drawbacks of wind and solar energy. We can heat no fewer than 40% of the homes and commercial buildings in our region with heat from waste water and surface water. The construction of this heat pump is therefore a wonderfully inspiring and concrete example for municipalities, energy companies and other partners!” 

Cees de Haan, Director of Asset Development at Eneco: “Together with the De Stichtse Rijnlanden Water Board, we are committed to accelerating the energy transition. With the installation that we are now building, it is possible to extract heat from sewage water treatment and to use it for the heat network in Utrecht and Nieuwegein. By the end of 2023 we will be able to provide approximately 20,000 households with sustainable heat. A wonderful example of a sustainable energy supply.”