BEST PRACTICE EXAMPLE
Sewage treatment plant for sewage sludge
Green gas for a
competitive price
FACTS & FIGURES
• Location: Beverwijk, the Netherlands
• Operator:
BioGast Sustainable Energy
• Feedstock: sewage sludge
Combination membrane and
cryogene technologies
• Biogas injected into gas grid:
1.4 million m3 per year
• Operating pressure of gas grid: 8 bar
• Investment: 1.375 million euro
• Commissioning date: 2011
BioGast has been producing
green gas since 2006 and is
the first independent producer
of green gas in and for the
Netherlands. In the BioGast
plant 4 in Beverwijk, the
Netherlands, sewage sludge
of some 160,000 inhabitants
is processed each year to
generate 1.4 million m3 of
green gas. The green gas is
sold to utilities company Eneco,
which supplies it to Orange
Gas as car fuel.
Dried and separated
Hoogheemraadschap Hollands Kwartier
(HHNK), the regional water board,
manages the overall wastewater treatment
process, during which wastewater and
sewage sludge are separated. The sludge
is fed into three fermenters, in which
the biogas is generated. The biogas
is then upgraded to green gas using a
combination of membrane and cryogene
technologies. CO2 is separated, washed
and liquefied.
The heat necessary for the upgrading
installation is provided by the waste heat
from the sludge dryer and the biogas
production process. The biogas is dried
and an activated carbon filter removes
hydrogen sulfide and other impurities.
Membrane technology supplied by Pentair
Haffmans is used to separate the green
gas and the CO2. The CO2 is then liquefied
and stored for further use, while the
green gas is fed into an 8-bar natural gas
grid. Part of the green gas is used to fuel
HHNK’s fleet of biomethane-fuelled cars.
Self-sufficient
In 2011 the BioGast 4 installation replaced
the BioGast 1, Biogast 1 had been in
operation on that site since 2006. Transfer
of production was smooth. This illustrates
the efficiency of BioGast’s approach,
which is based on a ‘plug-and-play’
principle using prefabricated installations.
Biogast 1 has now started a second
career in a sewage treatment plant in
Amsterdam.
Profitability
What initially started as a pilot project
is turning out to be a financially healthy
installation, which is financially selfsufficient based on the production of green
gas alone. Total investment cost up to the
injection point is 1.375 million euro.
About 1.4 million m3 of green gas is
produced per year.
Green gas is produced against market
prices and the project has a positive cash
flow. The project does not use government
subsidies, either for the installations or
Optimal solution: the biomethane is injected into the 8-bar grid,
used as vehicle fuel for the HHNK’s carfleet and the byproduct
liquid CO2 can be sold to the horticulture.
for feed-in of green gas into the grid.
Commercial production of CO2 would add
to the profitability of the project and is
currently under study.
Competitive cost price
The business model has a firm base in
producing green gas at market prices. The
cost price of the green gas produced can
compete with that of natural gas.
The green gas is sold to Eneco. The
utilities company supplies it to Orange
Gas, which sells it as car fuel in their
filling stations. Part of the green gas is
allocated to HHNK, where it is used for the
organisation’s fleet of biomethane-fuelled
cars. With rising oil prices, it is a costeffective alternative to fossil fuels.
The CO2 generated during the biogas
upgrading process is not currently sold
commercially. Part of the CO2 is used
to adjust the ph-value during the overall
wastewater treatment process.
It could, however, also be sold for use in
greenhouses or in industrial processes.
No extra requirements
The project was a prolongation of an
existing project, enabling processes to
run smoothly and cost-efficiently right
from the start. When BioGast stepped up
production, regional gas infrastructure
company Stedin initially formulated extra
requirements for the additional green gas.
The two organisations have since resolved
their differences; no extra requirements
are applicable to the additional feed-in.
Production and products
The future is likely to see expansion of
production and products.
Production is currently around 1.4 million
m3 per year. BioGast expects this to grow
to 1.9 million m3 per year by 2016.
Studies into the commercial production of
liquid CO2 are under way. If the results are
favourable, production could be set up in
the near future.
The Green Gas Grids Project
GreenGasGrids is a 3-year European
project co-funded by the Intelligent
Energy for Europe (IEE) programme.
It aims to move biomethane into
the mainstream and bring it on the
agenda of key EU and national bodies
involved in (renewable) energy and
natural gas. The consortium consists
of 13 energy agencies, scientific
institutions and industry associations
involved in biomethane, natural gas,
and renewable energy. They combine
expertise and market experience with
networks throughout the EU. The
project focuses on the most pressing
issues: sustainability, technical
standards, legislation and trade.
Geographical focus: Austria, Belgium,
Croatia, Denmark, Finland, France,
Germany, Hungary, Italy, Poland,
Slovakia, Spain, Sweden, Switzerland,
The Netherlands, United Kingdom.
This factsheet has been produced in
cooperation between Green Gas Grids
and BioGast B.V. For more information,
please contact:
Frederik Gast
Tel. +31 6 2429 4278
E-mail: [email protected]
www.biogast.nl
GREEN GAS GRIDS:
Alexandra Lermen
German Energy Agency
[email protected]
www.greengasgrids.eu
I N T E L L I G E N T
E N E R G Y
E U R O P E
FOR A SUSTAINABLE FUTURE