Potential analysis

A large proportion of the heat is used in our homes. Many buildings in Dresden have already been refurbished, especially since the 1990s. Nevertheless, there are many houses with poor energy standards that can be renovated in the next few years. Measures such as better insulation, modern radiators or lowering the flow temperatures help to save energy in the heating supply. However, the demand for heating will remain high in the future, especially in the old town, the new town and in large residential areas such as the prefabricated housing estates.

In industry, process heat - the heat required for production processes - is particularly important. Some processes run at relatively low temperatures and can be operated with large heat pumps in the future. For very high temperatures, such as those required for the production of semiconductor base materials, hydrogen or electricity for heating special furnaces will remain indispensable. Dresden has a high energy demand in industry, especially in the semiconductor sector. There are great opportunities here, but also challenges for the changeover.

There are numerous ways to utilise renewable heat in Dresden:

• Air heat: air-to-water and air-to-air heat pumps can be used in almost all parts of the city. They could theoretically cover up to 70 % of the city's useful energy requirements. There are limitations due to noise protection in densely built-up areas and the utilisation of the electricity grids.
• Geothermal energy: Heat can be extracted from the ground using ground collectors and geothermal probes. Collectors require a lot of space, geothermal probes less - but drilling is necessary. Overall, around a third of demand could be covered by geothermal probes.
• Groundwater: Groundwater is also a source of heat. In Dresden, there is a potential of around 230 GWh per year. However, utilisation is not permitted in water protection areas.
• Waste water: Both drinking water and waste water temperatures are subject to annual fluctuations, with winter temperatures often being significantly warmer than the outside temperature. This temperature difference can be utilised for heating with the help of heat pump technology. The potential for heat utilisation was investigated further for the sewage treatment plant in Kaditz. The potential is around 375 GWh.
• Waste heat: Many industrial plants and computer centres emit heat that has so far remained unused. SachsenEnergie AG estimates the potential at around 825 GWh. Initial projects, e.g. at the high-performance computing centre at TU Dresden, have already been launched.
• Thermal waste treatment: The steam generated during the treatment of waste can be utilised by turbines as a source of heat and electricity. There is currently no thermal waste treatment plant in Dresden, but if Dresden were to build its own plant, almost 300 GWh of additional heat could be utilised.
• Hydrogen: Dresden is to be connected to the Germany-wide hydrogen core network from 2032. Industrial plants in particular will then be able to run on climate-friendly hydrogen.
• Solar thermal energy: Solar collectors on roofs or open spaces can supply heat for hot water and heating. However, they can only be used to a limited extent in urban areas due to the space required.

Further information and the spatial distribution of the potential of renewable heat sources can be found in the energy atlas.

The analysis shows that Dresden has many opportunities to organise its heat supply in a climate-friendly way. A mix of energy saving, heat pumps, waste heat utilisation, the use of green hydrogen and renewable sources such as solar, ground and water energy can make the city climate-neutral by 2045. For this to succeed, the city, energy suppliers, industry and citizens must work together.