1. 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

2. Content Background Separation technologies Economic analysis
Biogas and Separation

3. 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

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

5. 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 down to kg P/ha on intensive pig farms.
The need for separation has been reduced
But the need in relation to biogas has increased 5

6. Separation technologies – Flocculation6

7. Separation with mobile decanter

8. Separation technologies – source separation8

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

10. 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

11. 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

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

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

14. 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

15. 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

16. Thank you for your attention