Biogas refers to a mixture of gases, predominately methane, produced by the breakdown of organic matter, in the absence of oxygen, by anaerobic microbes.
It works in a similar fashion to a cow’s rumen. It’s commonly produced from raw materials such as manure, plant material, green waste and food waste but can also be produced from crops like wheat and maize.
The gas is collected and used for the electricity generation, heat production and fuel transfer.
Germany is the largest biogas producer in Europe, with other countries becoming increasingly active in the area as the focus on renewable and sustainable sources of energy continues to strengthen.
Although the electricity generated by biogas plants can be bought by utility companies, biogas producers must market the thermal energy created through the process on their own initiative.
Much of the heat produced is fed into district heating networks as well as for personal use.
Biogas is also said to be making significant contributions to climate protection. Agriculture accounts for a large proportion of greenhouse gas emissions worldwide.
The fermentation of agricultural by-products like manure and energy recovery from the biogas produced could have an impact on climate protection by using it, rather than letting it escape into the atmosphere, making it a potential problem-solver for issues around intensive livestock farming.
Christoph uses 60t of organic material a day for input in the biogas plant. Half the material comes from his own farm in the form of manure and barn litter, and half comes from food waste provided by various partners he works with in the restaurant trade, hospitals and airports.
German dairy farmer Christoph Lupschen’s biogas plant cost about €4 million to build.
The full process through the biogas plant takes about 60 days. The anaerobic microbes live in large sealed airtight containers called digesters, where the biogas is generated.
Organic matter is supplied as feedstock for the microbes, much like grass and supplement feeds the microbes in a cow’s rumen.
Also like a rumen, the system requires “feeding” regularly so most are fitted with dosing systems that deliver material in small quantities several times an hour.
Temperatures in the digester reach 35-40C. The biogas created is transferred by a gas pipeline to the combined heat and power plant to be used for power or heat generation.
This process leaves behind high-quality fertiliser that can be used as a substitute for mineral fertilisers, and Christoph takes advantage of it.
“It means that everything is fully recycled back into the system, it’s a way of keeping the farm sustainable and lowering some costs.”
'It means that everything is fully recycled back into the system, it’s a way of keeping the farm sustainable and lowering some costs.'
The electric generator produces 800 kilowatts an hour of electricity that is used to power the farm as well as heating water for not only his farm, but the surrounding district. Any excess power is sold into the main power grid.
Germany’s shift towards more renewable sources of power by 2021 means there will be opportunity for more farmers to invest in this type of operation. However, with a price tag of €4 million (NZ$6.2m) it won’t be a viable option for many.
Christoph co-owns the biogas plant in partnership with a friend and says they receive no support from the government, despite it supporting the German government’s goals of being nuclear-free and moving towards more sustainable energy sources and farming systems. It will take about 20 years to pay off.
During this time he receives a fixed price for the power he generates, regardless of energy price fluctuations in the rest of the market, but this does mean substantial energy savings.
He says power normally sits at about 22 euro cents per kilowatt, but with his biogas plant he only pays about 9.5 euro cents.
The biogas plant helps to keep his farm sustainable and is a way for him to attempt to offset the costs of his dairy farm, which is not making him money, while also giving back to his community.
It contributes about 50% of Christoph’s income with the other 50% coming from the breeding arm of his dairy farm.
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