Bio-solar local heating supply – Gimbweiler (Rhineland-Palatinate)

Nahwärmeversorgung Birkenfeld GmbH

Gimbweiler has become a bio-energy village. The 86 buildings in the village of the Birkenfeld municipality have been converted from using heating oil to using a fully renewable heat supply. The interplay of solar thermal energy, photovoltaics and regional biomass enables a continuous supply of green energy.

Buffer storage of the bio-solar local heat supply system

Participating company

Nahwärmeversorgung Birkenfeld GmbH

Project location

Gimbweiler (Rhineland-Palatinate)


Mechanical engineering/heating/efficiency technologies

Technologies used

Local heating grid (4.4 km section), solar thermal energy (21% of the heat) and regional biomass, photovoltaics (73 kW), two buffer storage units (50 m³ each), battery storage (78 kWh) for internal consumption optimisation

Energy efficiency

Reduction of energy consumption by 320,000 kWh/yr

CO2 savings

580 t CO2e/yr



Payback period

7–8 years (on the consumer side)

Funding programmes

BMU (German Federal Ministry for Environment, Nature Conservation and Nuclear Safety) funding from the German National Climate Initiative; Rheinland Palatinate state funding from the ZEIS (Sustainable Energy Infrastructure) funding programme; KfW (German Credit Institute for Reconstruction) funding programme 271 Premium

In Gimbweiler (in the municipality of Birkenfeld), Nahwärmeversorgung Birkenfeld GmbH (NVB) won the tender for the construction of a bio-energy village, which it then planned and built. The local heating supply uses solar thermal energy, photovoltaics and regional biomass and is 100 per cent renewable. The newly constructed local heating grid, to which 86 buildings are connected, has been converted from using heating oil to using renewable energy (biomass, solar thermal). Every heating oil boiler system was replaced with an indirect heat transfer station that is connected to a local heating gird. Hydraulic balancing and differential pressure control with low volume flows allow for a high degree of temperature variation between flow and return. An energy management system ensures that energy consumption can be continuously monitored and controlled remotely. Another special feature is the integrated PV system that enables the heating system (circulation pumps) to operate with almost no CO2 emissions. The financing of the project was supported by three funding programmes (from the German federal government and the Rhineland-Palatinate government). The applicant overcame numerous obstacles to realise the project: convincing the residents, designing the business and operator type of the local heating grid, problems with procurement law and the financing of the local community’s contribution. The Gimbweiler energy team, headed by former mayor Martin Samson, overcame a lot of resistance and many setbacks to realise the project for the community, and it is important to emphasise their many years of commitment. The project was implemented at Birkenfeld University’s Environmental Campus in cooperation with the Institut für angewandtes Stoffstrommanagement (IfaS) [Institute for Applied Material Flow Management).

Buffer storage of the bio-solar local heat supply system


This project is a strong example for many communities in rural areas to follow and is easily transferable to them, as long as the appropriate funding can be raised.

Energy Efficiency Award 2021

Award winners 2021

Around 130 applications from Germany and around the world: the Energy Efficiency Award is once again a coveted award in the context of energy… Read more

Pictures: Foto EDG mbH