Since 2002, Danish pig producer Jens Peter Lunden has been making a profit by operating a GrønGas A/S biogas plant. Lunden sells off the excess heat generated by the anaerobic digestion plant to a nearby district heating company, generates electricity for the National Grid, and also reduces his farm’s carbon footprint.

Lunden, who farms at Asdal Hovegaard, near Hjørring on Jutland, originally began with a plant commissioned as a 625kW unit. That plant has since been upgraded to 1.4MW and includes a digestate separation unit.

Lunden is now preparing to install his second biogas plant, and recently recruited 35 other farmers to supply him with 200,000 metric tons of fiber and slurry, as well as energy crops from 1,000 hectares of land. Lunden said he believes this type of cooperation is the way forward for farmers who want to make money and invest in renewable energy.

Modest beginnings

Lunden was recently the keynote speaker at the Energy Now Expo 2011 in Malvern, the UK. At the conference, Lunden said he had set up his first biogas plant in an attempt to increase the nutrient value of his pigs’ slurry, reduce his mineral fertilizer bills and reduce his farm’s odor by spreading the disgestate by-product instead of raw slurry.

However, in order to start up his plant it had to be profitable, and this was where the renewable energy came in, as he has been able to sell the electricity and heat produced by the plant. This has also helped him cut the farm’s carbon footprint.

It was only in 2007 – five years after the plant was commissioned – that Lunden started to receive manure fiber from other farmers. However, he soon discovered this was a winning combination that allowed both him and the other farmers to benefit from the plant. His partners are all able to use the digestate to fertilize their land.

Lunden has 900 sows and takes his pigs through to slaughter. He also has 500 hectares of land where he grows winter barley, wheat and oilseed rape. Next year, Lunden plans to install a GrønGas 2 AD unit at a cost of Euros 200,000 (US$278,959). The GrønGas 2 will include a unit to upgrade the output so that he can provide biogas that is equivalent in quality to natural gas.

Bigger and better

Lunden calculates that in 2010 the plant used 22,000 metric tons of pig and cattle slurry, 150 mt of fiber from separated pig slurry, 2,300 mt of maize silage, 1,500 mt of waste grain (barley, rye and wheat), as well as 2,900 mt of glycerine and 2,000 mt of food waste from a nearby fishing port.


Operating the plant in 2009 led to a carbon dioxide reduction of some 6,000 mt. It also provided enough electricity for about 1,700 homes and heat for 900 homes. It also boosted the use of the nutrients in the manure, providing between 85% and 90% of the nitrogen available.

Lunden claims his proposed plant will be even bigger and better. “I cannot understand why more British pig producers are not going forward with their plans to build biogas plants,” Lunden said. “I have been able to increase productivity and profits by adding little improvements every year.”

Biosecurity questioned

Asked about biosecurity on his farm, especially with some food waste coming onto it for the plant, Lunden said “The vets come and inspect both the plant and the farm every year to ensure that bringing food and other waste onto the farm as feedstock for the plant does not compromise our biosecurity – and I always listen very carefully to what they say.”

Energy Now Expo 2011 conference chairman Oliver Harwood, who is chief surveyor at the Country Land and Business Association, pointed out that biogas is one of the most flexible renewable energies. Not only can it be used to generate electricity and produce heat, the gas can also be scrubbed and used as a transport fuel and injected into the natural gas grid.

Harwood also heads the not-for-profit Probiogas UK, which supports UK dissemination of international biogas experience. In addition, he has also helped force the government to rethink its classification of wastes used for on-farm biogas.

A great opportunity

Harwood believes there is a great opportunity for pig farmers to profit by working together in joint biogas ventures that could help them and join the growing band of energy generators. Benefits include greater energy security, fixed costs and lower carbon footprints, as well as helping to reduce on-farm odors.

In an effort to increase energy security, a number of European pig farmers are incorporating other renewable energy technologies, including solar photovoltaic systems and wind turbines, into their businesses to ensure they can generate heat and power for their farming operations at all times.