The future of residential energy - photovoltaics, heat pumps, heat grids, geothermal energy ...

The electricity and heat supply in residential buildings is to be completely renewable in the future. Germany wants to become climate-neutral by 2045 at the latest. But homeowners do not have to and should not wait that long. Climate-friendly heating and electricity generation is already possible today.

Photovoltaic systems generate climate-neutral electricity; heat pumps, heat grids and other renewable energies provide environmentally friendly heating and are now also suitable for existing buildings. When it comes to heat supply, the house should first be made fit for renewables. "This means measures on and in the building, such as insulation and hydraulic balancing of the heating system," explains Frank Hettler of Zukunft Altbau.

When it comes to power supply, the solution is on the roof. Photovoltaic modules are the only component of the house that brings in more than it costs. The photovoltaic system does not necessarily have to be oriented towards the south. An east or west orientation also provides good yields.

Connecting to a heating network is an option if this is possible on site. Heat grids will become increasingly important in densely built-up neighbourhoods in the coming years. The heat comes mainly from renewable heat sources - such as solar thermal energy or bioenergy plants.

Heat pumps allow a climate-neutral heat supply where there is no heating network. The Fraunhofer Institute for Solar Energy Systems ISE has shown that the heat generators also work well in existing buildings. The devices obtain the majority of their energy from their direct environment, the air, the ground or the groundwater.

Piece wood or pellet boilers come into consideration for buildings that cannot achieve a low-temperature level. In the case of listed buildings, this is often the only way to provide approximately climate-neutral heating without a well-insulated building envelope.

Deep geothermal energy has great potential for local and district heating networks in urban areas due to its use of geothermal energy, but has so far often remained stuck in planning and bureaucracy.

(Photo: © Klimahaus Bremerhaven, Erich Westendarp, Pixabay)