Abstract
The dependency of fossil fuels in the transport sector causes large emissions of carbon
dioxide. This problem can we reduce by using vehicle gas from digested solid manure and left
over of pasture. I have studied the potential for this in the county of Västernorrland. The
purpose is to investigate how much vehicle gas that can be extracted.
One central, large scale digestion and upgrade plant should be placed in Härnösand. The
amount of pasture and manure that is economical and practical available is enough to produce
2,7-3,5 millions Nm3 vehicle gas. It corresponds to 1 800- 2 400 cars, each driving 17 860 km
per year.
The heating value of the vehicle gas is 26-34 GWh. To extract this energy you have to supply
energy corresponding to a heating value of 4,9 GWh for transport of raw material and
digested sludge together with 13-14 GWh for process heat and electricity.
If the gas replaces petrol the emissions from the lifecycle of the fuel decrease with 5 600-7
400 ton CO2-equivalents. The emissions by the vehicle decreases with 640-840 kg NOx, the
emissions of hydrocarbon increases with 60-80 kg and the emissions of particles remains the
same.
The increased content of easy available nitrogen is about 40 tons, it can replace about 5 % of
the nitrogen supplied as synthetic fertilizer. The contribution to the nitrogen resource by
digested sludge is greater than its contribution to the supply of fuel.
The cost for the gas is 12-14 kr per petrol equivalent, that is little more than the today’s price
of petrol of 11,28-12,24 kr. Above all, it is the cost of transport that cause the high cost.
2009.