Jump to content
Powered by

Bioenergy from meadow orchards

A project called "Energiebündel & Flowerpower" ("Bundle of Energy & Flower Power") run by the "Netzwerk Streuobst Mössingen" (Mössingen meadow orchards network) has established a complex local recycling network for biomass from meadow orchards. The network involves the city of Mössingen, the neighbouring municipality of Nehren, the KFB institution for the physically disabled and their self-help work group called "Streuobst und Naturschutz" (meadow orchard fruits and nature conservation), a biogas operator from Nehren, a start-up company called Vital Carbon, a wood pellet company and first and foremost the owners of small orchards around the city of Mössingen.

Netzwerk Streuobst Mössingen is looking for effective ways to use meadow orchards. © Uli Eder

Netzwerk Streuobst Mössingen was founded ten years ago by a local agenda group and brings together associations, initiative groups and individuals with an interest in fruit from meadow orchards. The primary objective was to halt the decline in the upkeep and use of meadow orchards. Ulrich Eder from the network comments: “The main idea was to attract young families and encourage them to use meadow orchards.”

There are now many related activities that attract locals to the meadow orchards around Mössingen. These include traditional apple festivals, a cider seminar featuring a scenic walk through the meadow orchards, an apple week and the production and marketing of “Roter Mössinger”, a red prosecco made from pears. To make It easier to rent the orchards, the city of Mössingen joined forces with the network to set up a modern, online rental system with the very Swabian-sounding name, “mystueckle.de” (my little orchard). People can use the website to choose and rent an orchard area according to size, location and fruit type. Since the online system was set up in November 2015, 40 orchards have already changed hands.

Help with tree pruning

Green cuttings from orchards ready to be picked up. © Sabine Mall-Eder

But the network didn't stop there. One of the things they wanted to do to encourage the preservation of meadows orchards was to help people advertise and sell their fruit. Pruning was another key aspect. In 1965, there were still around 18 million fruit trees in Baden-Württemberg. The most recent survey, conducted in 2005, listed only 9 million trees, many of which were not maintained or pruned. If fruit trees are not pruned regularly, they age very rapidly, thus further accelerating the drastic decrease in the number of meadow orchards in Baden-Württemberg. 1

Netzwerk Streuobst Mössingen therefore considered the ways that the network could help orchard owners prune their trees. “People are usually out pruning their orchards on Saturday mornings, with a constant eye on the time so they can make it to the recycling centre before it closes for the weekend,” said Sabine Mall-Eder from the “Energiebündel & Flowerpower” project.

Most municipalities only have limited opening hours for delivery of green cuttings to a specific shredding area, and they are often not long enough. The idea was to make the opening hours more attractive and also offer a municipal collection service for green cuttings on the roads and paths through the orchards. The city of Mössingen’s collection service is now very popular and many orchard owners prune their trees more frequently. The shredded material from a test area of around 100 ha around Mössingen corresponds to a calorific value of around 70,000 litres of heating oil.

Infinite quantities of biomass

Using tree cuttings for energy production is not something that people often consider. ”Orchards contain infinite quantities of biomass, but it is not very efficient,” said Mall-Eder from the network that carried out the “Energiebündel & Flowerpower” project with funding from the Stiftung Naturschutzfonds Baden-Württemberg. The project set out to find out which were the best economic and environmentally friendly energy recovery paths for the area around the municipalities of Mössingen and Nehren. At present, green cuttings are brought to a pellet production facility in the municipality of Empfingen where they are used to dry the wood pellets. The first calculations have shown that it would make sense to use the wooden biomass as a regenerative source of energy in the Kastanienhof, a disabled institution which belongs to the KFB. Another option would be for the local energy association to run a wood chip heating plant that would be used to heat an outdoor swimming pool and a boarding school.

Besides finding ways to use the biomass resulting from pruning fruit trees, Mall-Eder and her colleagues are also working on solutions for grass recovery. A biogas plant in the neighbouring city of Nehren is now using grass to produce biogas. However, this is a very labour-intensive and therefore not very profitable option. Also, farmers still tend to prefer using grass in the traditional way for cattle feed for example, at least when the trees are not too close together to prevent mowing.

Biochar for the improvement of soil

Towards the end of the project, the partners identified another potential way of recovering orchard biomass. Prof. Dr. Michael Weiss from the University of Tübingen has developed a method using fungi to turn biochar, which is produced by carbonising wooden biomass, into a high-quality soil improver. Weiss’ start-up company, Vital Carbon, is planning to build a carbonisation facility in Mössingen at which point it will become part of the local orchard biomass recovery network. Weiss also envisages integrating people with disabilities into the project, so that the overall concept would take environmental, economic and social aspects into account. This would then be fully in the spirit of sustainable development.

“Can Mössingen do flower power?"

The city of Mössingen collects green cuttings from private orchards. © Sabine Mall-Eder

Although the project has now ended, the city of Mössingen continues to collect green cuttings from orchards. The cuttings are collected from orchards around Mössingen and brought to temporary collection sites that are also open to residents of Mössingen. The long-term plan is to integrate hedge and succession areas into the meadow orchard project as part of landscape conservation measures. In addition, the city of Mössingen grows many flowers in the city and has added species with higher energy yields to its annual flower mix. Another project currently running aims to find out whether perennial biomass-rich flower mixes are suitable environmentally friendly corn replacements.

The question “Can Mössingen do flower power?” posed at the start of the project can therefore be answered with a resounding “yes”. It is hoped that other cities and municipalities in the Swabian Alb area with their many meadow orchards and approximately 1.5 million fruit trees will develop similar local concepts.

Streuobstwiesen in Baden-Württemberg – Wie viele Obstbäume wachsen im Land und in welchem Zustand sind sie?
Christian Küpfer, Julia Balko, Nürtingen-Geislingen University of Applied Sciences, Horizonte 35/March 2010, p. 38-41

Website address: https://www.biooekonomie-bw.de/en/articles/news/bioenergy-from-meadow-orchards