Ten years of anaerobic digestion (AD) production in Denmark has been turning farm slurry into a cost-saving measure and financial outlet.

Danish energy supplier, Nature Energy, spoke during an Irish Co-operative Organisation Society (ICOS) information webinar about the prospects of bioeconomy.

The company currently has 13 active AD plants in Denmark while seven of them are suitable to produce digestate for organic farms. In addition, one plant is currently being built and four more are in the pipeline.

Nature Energy agronomist Michael Tersbøl said they use a ‘circular economy’ method which aims to support farmers financially.

“In working with farmers, we both have something to win but we both also need the partnership with the other to achieve this win-win situation.”

Financial

A large Nature Energy AD plant can collect up to 800,000t of feedstock per year, 80% of which is manure. This can produce enough energy to heat 15,000 homes every year.

The Danish energy supplier said that its plants also produce nutrient-rich green fertiliser with a higher value than raw manure.

The deep litter from the plants is converted into digestate which contains a higher nitrogen utilisation.

This means that farmers would save costs on fertilisers while also improving the environmental footprint of their farms.

Nature Energy said it also offers financial support to farmers to build slurry tanks.

The main products sold by Danish AD plants are biomethane, e-methane, liquid digestate and solid digestate fibre for fertiliser and soil improvers.

They also produce carbon dioxide which can be turned into a liquid and sold to the food and drinks industry or to carbon capture storage.

Tersbøl added that they often sell carbon gas to breweries to make beer and fizzy drinks.