The owner of Grøngas A/S has 850 sows producing 22,500 piglets of 7-30 kg, and 17,000 pigs for slaughter. The annual production of manure amounts to 14,300 m3.
The biogas plant has been established in connection with the production facilities at the farm. Before establishment of the biogas plant the farm had an annual fuel oil consumption for heating of 50,000 litres that has now been replaced by surplus heat from the biogas plant.

Fact box

Biogas and Energy Production
Amounts of biomass used for biogas production at Grøngas are approximately: 14,300 m3 pig manure, 4,000 m3 cattle manure, 1,250 m3 stomach-intestine content, 2,000 m3 of fatty waste products and 3,500 m3 of energy crops.
Dependent on the amount and quality of the biomass the annual biogas production is up to approx. 3.7 mill m3 which gives an electricity production of 8.4 mill kWh and a heat production of 17.7 mill kWh. The heat is used for process heating, heating of stables and residential buildings. The electricity produced is sold to the power grid.
The biogas plant provides environmental advantages by means of reduction of emission of greenhouse gasses, lower odour nuisance, improvement of the fertilizer value of the manure and reduced water and air pollution.

Supplementing with Energy Crops
Various energy crops, such as grass and corn silage, are fed to the plant via a dosing mixer. The energy crops are fed directly to the central heating module by means of a screw conveyor. In the central heating module the energy crops are heat treated and chopped with the more liquid fractions. The heating module complies with the requirements for heat treatment of Category 3 Waste according to EU regulations.
Energy crops provide the perfect alternative to purchase and use of organic waste products as the crops can be grown on the owner's own land, including fallow land. This ensures stable gas production in the plant.