Absolutely cleverly combined

Tradition meets innovation in Kirchberg BE: the farm community of the Aeberhardt and Savary families will soon be supplying electricity, heat and biogas – all energy sources from sustainable sources. This multi-energy hub on the farm will benefit the municipality of Burgdorf, which will be supplied with climate-neutral energy.

In addition to arable farming on 20 hectares, the Aeberhardt and Savary families also have a state-of-the-art free stall barn for currently 70 Red Holstein and Holstein cows. Source: CNG-Mobility.ch

The cow lies in the fresh straw of the modern loose housing and is not disturbed by the manure removal robot that makes its rounds. The robot is already collecting material for the biogas plant that will soon go into operation. The 70 Red Holstein and Holstein cows obviously feel comfortable in their new home, stroll through the wide aisles, help themselves at the feed table or go to the milking robot whenever they like: the farm community of the Aeberhardt and Savary families relies on state-of-the-art helpers for flexibility, such as an automatic feed pusher for grass and maize silage from one of the four high silos in addition to the milking robot. The new building is fully designed for animal welfare, sustainability and efficiency.

In addition to arable farming on 20 hectares of farmland, the Aeberhardt and Savary families also have a state-of-the-art loose housing system for currently 70 Red Holstein and Holstein cows. Source: CNG-Mobility.ch

That’s not all by a long shot, because the Bernese have gone from being farmers to energy farmers. They now also produce sustainable energy from the region for the region. For example, a photovoltaic system with a pike output of 117 kWh is installed on the roof of the new barn. And under the roof behind the box for the calves, which move to the Savary family’s partner farm in Wynigen after they have been watered, is the integrated biogas fermenter. Not a big green balloon as is so often the case: the hamlet is a listed building. This demanded innovative solutions, but also made the approval process and construction somewhat protracted.

It is still rolled up behind the calf box under the roof, but soon Haral’s gas balloon will be filled with biogas. Source: CNG-Mobility.ch

Via the plug flow reactor, which is perfectly integrated into the barn, the chopped substrate is continuously transported to the fermenter. A measuring device provides the gas processing plant with information about the fermentation process and the amount of raw gas to be expected. The raw gas from the fermenter is led via a winding pipe in the ground to the compact treatment plant in a 20-foot container. This has the advantage that the raw gas cools down a little on the way and water is already separated for the first time. Instead of going directly to the treatment plant, the raw gas is first sent to an activated carbon filter so that the membranes in the treatment plant have an easier time with the raw gas from the ultra-modern cowshed. In this way, Energiewirt GmbH can easily process it into “Energiewirt Biomethane” and feed it into the gas grid of Localnet AG.

Distribution box, additional active carbon filter station and the compact Apex container with processing plant for the raw gas are already ready. Source: CNG-Mobility.ch

In addition to liquid manure and the dung collected by the manure removal robot, co-substrates from the nearby Kunz Kunath AG feed mill are also used for the production of biogas. Positive for the energy farmers: the plant not only supplies biogas, but also high-quality fermentation slurry. Compared to conventional slurry, this is even easier for the plants to absorb, has lower emissions – and it stinks less. And in addition, expensive conventional artificial fertiliser can be partially replaced by a sustainable product. The biogas plant operated by Energiewirt GmbH, which was awarded the “Climate Protection Promotion Prize” by WWF Solothurn, feeds its CO₂-neutral biogas directly into the grid of Localnet AG via a five-bar line, so that part of Burgdorf’s municipal properties can be heated in a climate-neutral and energy-saving way.

The old cowshed now houses a huge boiler for the woodchip heating system of the Oberdorf heating network. Source: CNG-Mobility.ch

The small-scale biogas plant with feed-in is, like the photovoltaic system on the stable roof, only part of the energy production of the farming community, because the old cowshed next to the listed main house is now not simply used as a storage area. The heart of the Oberdorf heating network is now hidden here: an imposing boiler that is also fed with wood chips from the family’s own five-hectare forest. Here, too, the family Samuel & Vanessa Aeberhardt with brother Ueli Aeberhardt have managed to integrate innovative technology into the rural idyll with Wärmeverbund Oberdorf Kirchberg GmbH, which they founded together for this purpose: Instead of a silo, there is now simply a heat storage tank between the farm and Stöckli. From autumn 2023, the agricultural multi-energy hub will also be able to supply sustainably produced heat from its own farm, currently almost 2 MW, to surrounding properties.

Instead of a silo, there is now a (still) scaffolded heat storage tank between the listed main house and the smart Stöckli. Source: CNG-Mobility.ch

If you want to learn more about the project of the two families in Kirchberg BE or the biogas filling station on the farm of the Müller family in Thayngen SH, you should definitely make a note of Wednesday, 8 November 2023. A forum organised by Ökostrom Schweiz, the Swiss Farmers’ Association, the Swiss Association of Municipalities and Powerloop will be held under the motto “Bauerloop – every dung heap counts” from 12 noon in the market hall in Burgdorf. It will show how domestic electricity and heat supply can be realised in a climate-friendly way and how biogas plants and combined heat and power can be used to put Switzerland on course for the goal of net zero. (jas, 10 October 2023)