There is 76 billion Kilograms dung produced in 2015 by the life stock in Holland:
82% from cows
16% from pigs
2% from other animals (chicken, goat, sheep etc.)
This can in principle produce 4 billion cubic meters methane (natural gas grade) but actually bio methane (biogas), by anaerobic fermentation.
Good enough for 3.2 million households (families) thats about half the households in The Netherlands.
State of the Art is (2015 statistics say) that anually only 80 million cubic meters biogas is yet produced, good for 64,000 families.
This potential is good news, because farmers can’t handle so much dung, moreover they got to pay enormous taxes to get rid of it, and expanding of the life stock and business is not allowed.
I heard now twice on TV documentaries that Denmark is completely self supporting with respect to energy, only green energy, no fossils. Maybe Holland can go that way too and our biogas (potential) can be a big part of it.
Biogas good be 26.5% of energy demand in 2015.
REFERENCES (In Dutch):
Dutch gas distributors say only anual 1 billion cubic meters biogas can be produced maximal, good for 10% of the housholds (families) in The Netherlands