Case Story Denmark

Maabjerg Biogas Plant: Operation of a very large scale biogas plant in Denmark

June 2014

MISSION AND VISION

The Maabjerg BioEnergy biogas plant, one of world’s largest, was designed primarily to treat animal slurries and eventually to form part of a biorefinery concept (www.maabjergenergyconcept.eu). The biogas plant itself was taken into operation in January 2012 and is operating at full capacity. The biogas plant was born as an environmental project aiming to reduce runoff of nutrients into groundwater, rivers and bays, while contributing to develop the local farming economy and preserving employment. The aim was furthermore to support environmentally friendly energy production by exploiting biomass resources for the benefit of the local community. Farmers, represented by the Holstebro-Struer Farmers Association and the Holstebro Fur Breeders Association, in collaboration with the neighbouring utility companies Vestforsyning and Struer Forsyning, joined forces to establish Maabjerg BioEnergy. Maabjerg BioEnergy which is a key part of the future concept of creating a biorefinery centered around production of 2nd generation bioethanol from straw.

INPUT AND OUTPUT

Maabjerg BioEnergy is a plant of unprecedented scale that processes up to 800.000 tons of biomass yearly, of which about 500,000 tons are liquid and solid manure, supplied by the local farming community as shown by Figure 2. Along with manure, the plant co-digests wastewater sludge, dairy waste and food waste, producing 18 million Nm3 biogas for use in district heating and electricity generation, as well as digestate for use as fertilizer and fibres, as shown in Table 1 and Table 2.

As the Green Line mainly processes animal waste and the Industrial Line processes sewage from households, these two lines are operated separately. This means that it is possible to use digestate from the green line as crop fertilizer without any problems. The digestate from the industrial line is not spread on the soil for crop production, but separated into fibers and liquid. The liquid is returned at the waste water treatment plant and the fibre fraction is sold to a company which either incinerates it for energy generation, or applies the fibres as soil conditioner in forest areas.