While Denmark is leading the way to allow pig producers to play a bigger role in biogas production to generate electricity and supplement the country’s national gas grid, producers in the UK are close behind in their desire to exploit nature’s resources to help them generate green power.

While it is generally accepted that large, centrally-based anaerobic digestion (AD) plants using a combination of animal manures, food waste and other organic residues to produce high-quality gas will be part of the country’s future renewable energy mix, the question is how can this benefit the average-size pig farmer?

They simply do not have the necessary resources to invest in large-scale projects, or produce enough slurry to feed a big plant.

Regional biogas grids  

The answer being investigated by the Danes could involve farmers co-operating with local municipalities to create a system of regional biogas grids to include a series of pipes connecting pig farms to the nearest central plant to transport slurry and other farm waste to it.

The thinking goes that the farmers could then all share in the profits generated by the plant through its sale of electricity and heat. They would also be entitled to some of the organic fertiliser, a by-product of the AD process.

Bruno Sander Nielsen, chief executive of the Danish Biogas Association, believes this could be one way forward, although he points out that researchers in Denmark are also investigating opportunities to develop small but viable farm-scale AD plants that could use grass and other organic farm waste together with slurries to improve gas production.

It is understood that the Danish government will be considering all these innovative proposals late this year when it is planning a debate on its new Green Plan. Nielsen says that he hopes everything will be decided and in place to allow the industry to move forward in 2011.

“Pig farmers are anxious to move forward, because anaerobic digestion can help them reduce their carbon footprint and turn their waste into an asset,” says Nielsen. “We already have plans for 25 to 30 big biogas plants that are ready to go ahead, as soon as they get the green light.”

Whatever happens, Nielsen is convinced that biogas will play a major role in renewable energy in Denmark and other parts of the world, mainly because the AD process helps reduce waste mountains, as well as greenhouse gas emissions, while providing consumers with fossil-free heat and power, as well as transport fuel. It also allows pig producers to turn their slurry and other organic farm waste into a valuable asset.

Renewable energy technologies  

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Meanwhile, in the UK, a growing number of pig producers are looking at a variety of renewable energy technologies to help them cut their power bills. They include fitting solar panels to generate electricity or to heat water on their pig buildings, erecting wind turbines, or investing in ground heat pumps as well as AD.

British Pig Executive environment expert Nigel Penlington comments: “There is definitely more interest in renewable energy here now and I know of several producers who are planning to invest in one or other technology in the near future.” However, he continued it was taking some time, as farmers investigated which option was the most suitable and then obtained all the necessary permits and planning permissions.

“I think that once we have one or two people actually setting up renewable energy units and they start talking about the benefits, we will see a rush of other producers following them. Maybe we need some more on-farm demonstration units to get the ball rolling here,” says Penlington.

He suggests that companies providing pig buildings could help move the renewable energy agenda forward by including some of the technologies, such as solar panels, in their new designs.

Geography plays important role  

As far as Denmark’s idea of local underground biogas networks was concerned, he felt they had possibilities in regions where pig farms were relatively close to one another, such as Denmark. But it wasn’t really practical in countries such as the UK, where pig units were usually some distance from each other, and connecting them all up would be too costly.

Meanwhile, the Danish-based international AD plant builder and developer, Xergi, has developed a special “focus plant” for farmers looking at the 500kw power output range.

UK general manager Colin Steel said his company had designed the new plant (see diagram) to help farmers in the UK and Ireland looking to achieve a return on their investment in AD equipment by optimising and simplifying the design layout.

“It’s straight-forward in design and build, with a few selected options available, while maintaining the principle core of the company’s design,” says Steel. He claimed the new plant is competitively priced and offers low lifetime running costs.