Wastewater heat NRW: The hidden energy source for our cities!

Wastewater heat NRW: The hidden energy source for our cities!

A promising project is currently being launched in North Rhine-Westphalia that not only advances climate protection, but also supports the energy transition. The Wastewater Heat NRW initiative, carried out by NRW.Energy4Climate in collaboration with energy suppliers, water management, sewer network companies and the housing industry, has set itself the goal of expanding the use of wastewater heat in the state. But what exactly is behind this innovative idea?

Around a dozen projects for using wastewater heat are already underway in North Rhine-Westphalia, and the potential is enormous. Wastewater from sewage treatment plants or canals provides a constant temperature of around 10 to 20 degrees Celsius, making it an economical source of heat. Duisburg, for example, uses the residual heat from treated wastewater to supply more than 1,000 households. But a wastewater heat pump is also used in Lemgo to help generate district heating. “Wastewater heat is ideal for densely populated areas, apartment buildings and facilities such as retirement homes,” the initiative gives an insight into the diverse possible applications.

The advantages of wastewater heat

The use of wastewater to generate heat not only offers ecological advantages, but also economic ones. Wastewater usually has small seasonal temperature fluctuations and can be used both in the cold season to support heating and in the summer to cool buildings. In metropolitan areas, high amounts of wastewater often correlate with a high demand for heat, so that the technical development of this heat source is both practical and sensible. Heat exchangers and heat pumps make it possible to use heat efficiently and integrate it into existing heating networks.

The estimates show that in North Rhine-Westphalia there is a theoretical potential of around 1.6 gigawatts of thermal output from both sewage treatment plants and the sewage system, which could cover around ten percent of the state's total district heating needs. However, this potential has so far only been used to a limited extent, which means that there are still many unused heat sources available.

A look into the future

The initiative aims to initiate several hundred projects in North Rhine-Westphalia and thus become Germany's leader in the use of wastewater heat. The key to successful implementation lies in close cooperation between municipalities and operators of sewer and sewage treatment plants. In order to realize the full potential, local decisions and strategies are essential.

In order to provide assistance to those responsible in municipalities, the Association of Municipal Companies (VKU) and the German Association for Water Management, Sewage and Waste (DWA) have published a helpful guide on the efficient use of wastewater heat. This brochure deals with legal and technical issues and is intended to serve as a guide to promote exchange between the various actors.

In addition to the opportunities offered by wastewater heat, other sustainable heat sources such as industrial waste heat and geothermal energy are also important. There is promising geothermal energy potential, especially in cities like Krefeld and Münsterland, which should also be incorporated into thermal planning. NRW.Energy4Climate provides municipalities with a checklist to determine this potential.

The future of wastewater heat utilization looks promising. Through innovative projects and the smart mix of various renewable energy sources, North Rhine-Westphalia could make a decisive contribution to climate protection and at the same time improve the local heat supply. So let's see what the coming years will bring and what possibilities wastewater heat can still develop. For detailed information about the initiative and the projects, visit the website Solar server, energy4climate and kommunen.nrw.