Solar District Heating Supply "Bundorf"

District heating from green electricity

The Bundorf reference project is a district heating project that is mainly fuelled by solar power and based exclusively on renewable energy sources. At its centre is a heating centre with two heat pumps, an electric boiler, a wood chip peak load boiler and a buffer storage tank with a large storage volume of 75 m³.

The main source of energy for this project is solar power from the nearby Bundorf solar park. Of the 125 MWp of photovoltaic modules installed there, 1.5 MWp is available for heat generation. The electricity reaches the heating centre via a 20 kV direct line.

The district heating generated in this way is distributed from the heating centre to the connected private and public buildings in Bundorf via a 1.6 km long distribution network.

More efficiency with data analytics

This new type of district heating system has demanding optimisation targets that can be fully achieved with the mondas® data analytics platform:

• A reliable heat supply on a renewable basis. At any time, in any weather.

• The most cost-effective utilisation of the solar power generated

• Flexible adjustment of heat storage and solar power feed-in to the current heat demand and the current solar power supply and feed-in price.

Data-driven optimisation and control

For this purpose, the time series data from over 500 installed measurement and control points are continuously analysed and interpreted by the mondas® data analytics platform practically in real time.

Algorithms calculate the optimum operating strategy and convert this into control impulses that lead to a modified, optimised operating mode.

This is done fully automatically, also with the aid of external weather data and forecasts and the current electricity exchange price.

A selection of the numerous control options:

Grid-compatible operation: When solar electricity exchange prices are very low, heat pumps and electric boilers are put into operation, as feeding electricity into the grid would be uneconomical at this time.

Predictive storage charging and withdrawal strategies: Forward-looking grid operation is implemented thanks to extensive data recording with the integration of weather forecasts.

Flexible storage management: Overcharging the buffer storage tank by flexibly setting the target temperatures in order to efficiently utilise the energy generated during high solar power yields at midday.

Machine learning for continuous improvement

The mondas® data analytics platform uses advanced machine learning methods to continuously refine and adapt the control algorithms. Training data is fed in and evaluated during operation in order to continuously optimise the efficiency and profitability of the system.

The Bundorf solar district heating project is an outstanding example of advanced sector coupling with renewable energies.
For a secure, affordable and sustainable local heating supply.

Energy cooperative as operator

The system was planned and installed by MaxSolar GmbH. It is owned and operated by egis Energiegenossenschaft Inn-Salzach eG. The plant was commissioned in autumn 2023.

EGIS eG (EnergieGenossenschaft Inn-Salzach eG) is a key player in the project, as it is also responsible for operating the district heating network and the heating centre.

In addition, it holds 40% of the solar park via Bürgersolarpark Bundorf GmbH & Co. KG, while the remaining 60 % is held by the operating company PV Bundorf GmbH & Co. KG, which belongs to MaxSolar GmbH.

Project of superlatives

The Bundorf solar district heating project is considered the largest solar sector coupling project currently in operation in Germany. In 2024, it received the prestigious Smarter E Award 2024 in the ‘Outstanding Projects’ category.