Low-temperature district heating networks. The basis for modernizing the heat sector.

Almost 40 % of the building stock in Poland is heated by district heating, with coal and gas still being the predominant heat sources. Due to climate change and increasingly volatile energy prices, fossil fuels need to be replaced by alternative heat sources. Renewable energy and waste heat have the potential to massively reduce the national carbon footprint. These local sources mitigate the price risks of imported energy sources, not to mention the various other benefits that result. Such a strategy is facilitated by lowering the current high grid temperatures, which allows for efficient integration of alternative heat sources into the district heating network. With few exceptions, renewables and waste heat sources are often available locally - but at low temperature levels, so heat pumps are required to utilize their potential.

However, efficient heat pump operation requires a significant reduction in the current temperature level in the grids, which is why a continuous temperature reduction process must be established.
In addition to the fundamental reduction in heat demand, e.g. through the thermal modernization of buildings, the measures to reduce the temperature affect the design and operation of the district heating networks. In many cases, however, an immediate temperature reduction would also be possible, provided that the applicable laws and directives would allow this.

This report lists the most important measures in this respect and quantifies their potential at national level. Supplemented by a case study, the report shows an approach for redesigning existing networks in practice.
This report was commissioned by the Polish think tank 'Forum Energii' in cooperation with TEP Energy, AGH University of Science and Technology and Kelvin Spółka z o.o.