Decarbonizing the heating sector is considered one of the greatest challenges of the energy transition. While the expansion of renewable energy sources has made significant progress in the electricity sector, the heating sector still lags behind—accounting for over 50% of final energy consumption in Germany. This makes it all the more important to identify and establish scalable, climate-friendly alternatives to fossil fuel-based heating systems. One of these alternatives is increasingly coming into focus for municipal utilities, planners, and local governments: cold district heating, or so-called cold networks. Technically, cold district heating is based on a low-temperature district heating network that utilizes environmental heat sources such as geothermal energy, groundwater, waste heat, or solar feed-in—typically at flow temperatures between 8 and 20 °C.

Flexibility is the key:

In principle, virtually any waste heat source can be integrated if the temperature in the loop is low. The benefits for consumers can be even greater: the heat is brought to the required temperature level in a decentralized manner via heat pumps installed in the buildings. This makes it possible to supply even clusters of buildings with varying thermal standards. Due to the low network temperature, there are hardly any distribution losses, and heat demand can be met in a highly efficient manner tailored to actual needs. Whether cold networks make economic sense depends on various factors. In urban areas, traditional district heating is likely to be successful. Far outside cities, individual systems will certainly predominate. In between, an economically viable urban area can be developed if there is sufficient density of cold local heating providers and consumers. From a planning perspective, this separation of generation and delivery opens up new flexibility: cold local heating enables cross-sector solutions with PV electricity, ice storage, renewable recooling, and seasonal intermediate storage. At the same time, its modular structure enables easy integration into existing neighborhoods as well as a future-proof supply for new development areas. With the amendment to the Building Energy Act (GEG) and municipal heat planning, as enshrined in the Heat Planning Act (WPG), cold district heating is increasingly playing a key role.

The first projects involving cold networks are currently being launched in Germany.

This demonstrates how the early involvement of stakeholders—from network operators and housing associations to individual citizens—can lead to the development of sustainable models that combine technology, economic viability, and public acceptance. The key question will be who should operate the cold networks. Will it be the district heating providers, who are already facing criticism due to their pricing policies, or will other stakeholders take over the market? Will there be a mandatory connection requirement, or will the decision be left to individual building owners? What about supply security if seemingly reliable waste heat sources are unavailable for technical reasons? Must the network operator maintain sufficient redundancy?

Last but not least, we need a pricing model that is attractive to both suppliers and consumers! From the perspective of heat pumps, cold networks are a key component. Let’s work to ensure that cold networks become a central focus of heat planning!

Read more on the AI portal.

Yours, Prof. Dr.-Ing. Uwe Franzke

Publisher