Autumn 2023 EN

BIOGAS JOURNAL | AUTUMN_2023 ENGLISH ISSUE
Helfried Welsch. Welsch is also a representative of
Stadtwerke Trier (SWT), which holds 51 percent of
Biogaspartner Bitburg GmbH, along with KNE (15
percent) and the private waste management company
Luzia François (34 percent) as shareholders of the
company. The interconnected system received strong
support from the state of Rhineland-Palatinate,
which also influenced the speed of implementation
of the upgrading project: “We were able to complete
the regional planning procedure for the entire raw
biogas route in the record time of nine months,” says
Welsch. All the necessary approvals for the pipelines
and the plant were obtained in just one year.
Perfect Site at Bitburg Airport
Bitburg Airport was suitable as a location for the upgrading
plant for two reasons: firstly, the site was already
designated as an industrial area, and secondly,
it was close to an existing natural gas grid. “If you
have to build a longer natural gas connection for a
plant like that, it significantly reduces profitability,”
says François. It is not possible to determine the maximum
distance at which it is worth sourcing the raw
biogas in a general sense. The viable catchment area
depends on the available gas quantity.
For the project, a transfer station was installed at
each biogas plant, where the raw biogas is cleaned
using activated carbon filters, then compressed,
cooled, and injected into the biogas collection pipeline.
The latter has diameters ranging from DN 125
to 250 and was laid together with fiber optic cables,
which is used, among other things, for control via a
central process control system. At the processing site,
the biogas is initially stored in a freestanding doublemembrane
gas storage with a capacity of 5,300 cubic
meters (m 3 ) made by Sattler Ceno TOP-TEX GmbH.
It then enters the upgrading unit, which is located in
several containers right next to the storage. There,
using the Pressure Swing Adsorption (PSA) process
from ETW Energietechnik, approximately half of
the volume, consisting of carbon dioxide (CO 2
), is
removed from the gas. This is done in six interconnected
columns. According to the manufacturer,
the ETW SmartCycle PSA gas purification process is
characterized by simple process control, high availability,
and insensitivity to varying raw gas qualities.
Marketed as “Regional Eifel Gas”
The upgrading unit is operated with regionally generated
green electricity, which is abundant as the region
has a renewable energy share of 160 percent in
terms of electricity. In this way, approximately 1,000
normal cubic meters of biomethane per hour (Nm 3 /h)
are produced from about 1,800 Nm 3 /h of raw biogas.
The SWT primarily use the green regional energy for
efficient electricity and heat generation in decentralized
combined heat and power plants, providing an
Next to the storage facility (left, partially visible) are
the upgrading unit (center of the image) and the
injection facility (right).
Wolfgang François (left) and Helfried Welsch have
overcome numerous challenges and are ready for
new projects.
ideal complement to the volatile electricity production
from solar and wind sources.
Delivery contracts have been concluded with the participating
farmers, to regulate, among other things,
the minimum injection of raw biogas. Although provisions
were made for certain price increases, the
current price jumps in the energy markets are not
covered. “We need to find a different compensation
system for those cases,” Wolfgang François said when
talking about the consequences. “A balance between
stability and flexibility” has to be ensured in the process.
The dramatic price development is not only an issue
in the gas sector, but also in the increased electricity
costs, which have significantly raised the cost of
the purification process. However, this also means
that “currently, the electricity prices are so at-
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