Largest Heat Pump in The Netherlands Taken into Operation

Eneco and water authority HDSR (Hoogheemraadschap De Stichtse Rijnlanden) opened the country’s largest heat pump in Utrecht. Eneco will use the pump to take heat from HDSR’s treated wastewater and turn it into a new source of energy for the heating grid. Approximately 20,000 households in the municipalities of Utrecht and Nieuwegein will now have sustainable heating.

The heat pump has been installed on the site of the Utrecht wastewater treatment plant and was opened by Nanda van Zoelen of HDSR and Eneco’s Chief Operating Officer Assets Karen de Lathouder. With Lot van Hooijdonk of the Utrecht Municipal Executive and Huib van Essen of the Utrecht Provincial Executive in attendance, they declared the largest heat pump in the Netherlands officially operational.

Reusing treated wastewater
Aquathermal energy is a viable way of making the sources for supplying heat more sustainable, in particular using hot water from a wastewater treatment plant situated right in the middle of an urbanised area. That is the reason for this partnership between Eneco and HDSR. Every day, the heat pump will draw residual heat from around 65 million litres of treated wastewater. That water, from showers, kitchen taps, dishwashers and washing machines, has temperatures ranging from 12 degrees in winter to more than 22 degrees in summer.

Thanks to the new heat pump, that heat will no longer simply dissipate, but instead the temperature of the treated water will be reused for the heating grid. A heat exchanger draws the heat from the wastewater, after which the large heat pump increases the temperature to 75 degrees and the water is fed into the heating grid. The overall installation includes a heat buffer of around 18 metres high and 18 metres across to make sure that enough heat is available at all times. Every year, it will supply up to 20,000 homes with sustainable heating.

Climate-neutral
Eneco and HDSR both have ambitions to become climate-neutral. Their combined exploration of possibilities to improve their sustainability has led to this major improvement for the heating grid in the municipalities of Utrecht and Nieuwegein, which share the ambition to become climate neutral. The new heat pump will save 30,000 tonnes of CO₂ per year.

Our wastewater treatment installations treat the waste water produced by our residents and businesses, which is a process that continues day and night. We’re excited that the heat in that treated wastewater will now be given a useful purpose and heat around 20,000 households. This new application means a significant drop in the volume of fossil fuels that are needed. We are very proud of this and our efforts to help create a sustainable and circular society.

Nanda van Zoelen of HDSR

Karen de Lathouder, Eneco’s Chief Operating Officer Assets, added, “Thanks to our partnership with HDSR, we can use heat in a circular process. People use heat in their homes, and we then reuse it to supply households with new heat and hot water. This is an excellent way of making our heat more sustainable and accelerating the pace of the energy transition.”