Biomethane Plant Oberlauterbach-Hallertau
Location: Region Hallertau, one of the largest hop cultivation areas in the world
Plant type: EUCO Titan 11500G, 11,5 MW (gas)
Feedstock: Hops and maize silage
Production Residues from Hop Cultivation
Hops grown in Hallertau are used for brewing beer worldwide. But only the hop cones are required for this process. What can be done with the rest of the plant? The conventional method is to shred the plant and use it as a fertiliser.This is, however, not required at the time of harvesting. Complicated and cost-intensive storage is thus necessary.
In addition the plants contain spikes that are used to attach the shoots to the frames. This is problematic both for transport as well as for use as a fertiliser. The chaff is virtually unusable without pretreatment.
How to Make Vine Chaff usable
The idea to construct a biogas plant was conceived in 2005 by Franz Högl and his sister Rita Högel, operators of the composting and recycling company 'Högl Kompost und Recycling'.
The first step involved developing a process to filter out the spikes with the help of magnets. The vine chaff could thus be used for energy production.
A Demanding Substrate
The vine chaff is a demanding material rich in fibre with high dry matter content. The plant system developed by Schmack Biogas thus uses a two-stage process. It consists of three horizontal fermenters and four round fermenters.
The substrate is first liquefied in the horizontal fermenters so that lower agitator power is required during the second fermentation stage. This first stage not only facilitates hydrolysis, but 50% of the biogas output is already recovered. The maximum gas yield is achieved by combining both fermenters.
A Closed Cycle
The resulting biogas is treated to obtain natural gas quality and then fed into the local natural gas grid.This is used to supply 9,000 households annually with electricity and another 2,000 households with heat.
Following the biogas process, the fermentation residue is reused as fertiliser on the fields - at a time when the fertiliser is actually needed.