Costs of slurry separation technologies and use of the solid fraction for biogas - A Danish perspective Senior Researcher Brian H. Jacobsen Institute of Food and Resource Economics University of Copenhagen E-mail: Brian@foi.dk

Content Background Separation technologies Economic analysis Biogas and Separation

Background A total of 3% of all slurry is separated in Denmark on 51 plants No use of high technology separation Half of the separation is related to pig production and the other half is from biogas plants 44% of the solid fraction is exported to other farms, and only 3% burned 40% is using screw press, another 40% is conveyer belt and the rest is decanter

Separation with mobile decanter Separation of slurry in DK Source: Farm Advisory Centre 4

Decreasing use of separation An incentive to reduce land ownership when using separation has now been removed Low income on pig farms for some years Decrease of livestock units of 18% since 2007 P-surplus has been reduced as feeding norms change, reducing application from 35-40 down to 25-30 kg P/ha on intensive pig farms. The need for separation has been reduced But the need in relation to biogas has increased 5

Separation technologies – Flocculation 6

Separation with mobile decanter

Separation technologies – source separation 8

Separation technologies – separation efficiency (content of solid fraction in %) Decanter Flocculation Source separation 9

Separation technologies analyzed Decanter Flocculation Source separation Area (ha) 203 Transport distance (km) (solid fraction) 30 N-efficiency (%) 63 62 56 Excess K Yes No 10

The economics of separation (1,000 DKK) Baseline Decanter (mobile) Flocculation Source separation Separation 124 149 Transport of solid fraction 0 / 128 25 94 Mineral fertiliser 58 / 75 14 26 57 Total costs (1000 dkk) 181 / 459 384 503 598 Per tonne (dkk/tonne) 21 / 54 46 61 72 Per pig (dkk/pig) 10 / 26 21 28 33 1,000 DKK = 135 € 11

Will biogas production increase from 2,5 PJ today to 13 PJ in 2020? !!! 12

A new option might be to upgrade the biogas to be included in the natural gas net

New energy support Biogas plants get a higher price for producing green electricity The higher price is now linked to the production of combined heating and electricity An increase in biogas production will increase production costs and make it more difficult to find buyers of heat => sales price has to increase New payment approach could help biogas plants, but could also increase competition with other sources of biomass (wood pellets from Canada) 14

Conclusions The incentive to use separation on farms has been reduced in recent years The need to use separated slurry in biogas has increased in order to improve gas production per tonne The biogas production is not very viable at the moment and so the expected increase is not likely Another way forward is upgrading the biogas to the sell to the natural gas net Farming is playing a more important role in trying to find green energies (biogas, straw, energy crops etc.) 15

Thank you for your attention