Page 162 - Sustainable Cities and Communities Design Handbook

Sustainable Towns Chapter j 7 139

Transport
With regard to transport, the project is heading for a solution in which the
vehicle fleet consists of bifuel cars (using biogas in combustion engines),
electric cars, and plug-in hybrid cars. To implement as much electric driving as
possible, it is suggested to implement cars that combine the use of batteries
with fuel cell driving based on either methanol or hydrogen. The specific
proposal calculated in the following discussion assumes that motorcycles and
mopeds (4 GWh) and vans and busses (25 GWh) are converted to biogas,
hydrogen, or methanol in the ratio of 1:1. Of the remaining transport demand,
10 GWh is converted into biogas in the ratio of 1:1; 50% of the remaining
demand is converted into electric driving (1 kWh of electricity replaces 3 kWh
of gasoline due to improved efficiencies); and the rest into fuel cellebased
driving, replacing 2 kWh of gasoline by 1 kWh of methanol or hydrogen. In
total, 165 GWh of gasoline and diesel are replaced by 10 GWh of biogas,
21 GWh of electricity, and 61 GWh of methanol.

Biogas Plant and Methanol Production
Partly to be able to produce methanol for transportation and partly to replace
natural gas for electricity and heat production, the project includes a biogas
plant utilizing 34 million tons of manure per year for the production of
225 GWh of biogas. The facility itself consumes 42 GWh of heat to attain the
optimal digestion temperature and 7 GWh of electricity.
The biogas can be converted into methanol with an efficiency of 70%.
Consequently, the production of 61 GWh of methanol is expected to consume
87 GWh of biogas. However, the production of methanol will provide 17 GWh
of heat, which can be utilized for district heating.
Methanolmayalsobefullyorpartlyproducedbyelectrolysis.Moreover,inthe
end, the cars may consume hydrogen instead of a certain share of the methanol. In
such case, part of the biogas will be replaced by wind power instead.