The Vuorenmaa dairy farm, in Haapavesi, Finland, has 180 cows that produce milk for Valio’s local dairy. For years, the farm has used manure to generate electricity and heat for own use through its in-house biogas plant. For the first time, this biogas has begun to fuel a milk truck as Valio’s first step in resetting milk’s carbon footprint to zero by 2035.
“The farm’s biogas plant currently produces roughly 1 900Mwh of biogas every year. We were overhauling the plant’s equipment and decided to expand its functions to produce biogas fuel. The milk truck from our local dairy at Haapavesi can fill up at our farm at the same time as they collect our milk.
“In the future, the fuelling station near the farm will also provide biogas for passenger cars”, says Janne Vuorenmaa, who runs the farm with his brother and family.
Initially, half of the gas they produce will be refined into biomethane, which is suited for use as vehicle fuel. If all the gas were to be used for the milk trucks, it would be enough for a mileage of over 350 000 kilometres per year. For now, there is only a limited amount of biogas for passenger cars. It will be possible, however, to increase the plant’s refining capacity to meet demand.
Manure-based biogas
“The biogas plant forms part of our farm’s regular nutrient circle. It transforms the nutrients in the manure into a form that is more useful in the fields, lessening our need to buy in fertilizer. It also improves the farm’s self-sufficiency when it comes to energy. Selling farm-produced fuel is another business opportunity”, adds Janne.
“Using biogas can reduce fuel’s lifecycle greenhouse gas emissions by up to 85 percent compared with diesel, which is what our milk collection and distribution trucks currently run on. At the same time, the dairy farm’s own carbon footprint reduces significantly, by one fourth or fifth, depending on the method of calculation.
“This dairy farm is a fantastic example of the ways in which farmers can solve environmental and climate challenges together with local businesses. At the same time, the farms can create new business, while improving our fuel-related self-sufficiency.”
Animal welfare
Says Petteri Tahvanainen of Viola, “Our job is to improve farm profitability as well as animal and human wellbeing. As far as I know we are the first in the world to offer a sustainability bonus to our farmers who invest more in animal welfare than required by law.”
“Some people may say that such as small act is not enough to save the .world, but we are excited to be a part of a chain that can result in concrete reductions in greenhouse gas emissions in the places that we live and breathe.”
How is biogas made?
The manure is fed to the biogas plant through a pipeline from the barn. Other matter, such as grass or spoiled feed can be mixed in the manure. The mixture is pumped into the biogas reactor, where it decomposes in an anoxic container. The gas rises to the top of the reactor, from where it is collected and purified for use. This process takes 30–40 days.
In biogas production, the manure’s fertilizing capability improves, and the smell is removed. The manure turns into a material of uniform quality that is so rich in nutrients that it is possible to reduce the use of commercial fertilizer. The refined manure produced in the biogas plant can also be separated into dry and liquid fractions.
The liquid, which contains the nutrients, can be used to fertilize the fields. The dry fraction, on the other hand, is so dry and high in quality that, in addition to its use as a fertilizer, it is possible to use as litter for the cows’ bedding instead of peat or sawdust.
