The major non-technical barriers are restrictions or prior claims
on use of land (food, energy, amenity use, housing, commerce,
industry, leisure or designations as areas of natural beauty, special scientific interest, etc.), as well as the environmental and ecological
effects of large areas of monoculture. For example, vegetable oils
are a renewable and potentially inexhaustible source of energy
with energy content close to diesel fuel. On the other hand, extensive
use of vegetable oils may cause other significant problems
such as starvation in developing countries.
The vegetable oil fuels were not acceptable because they were more expensive than
petroleum fuels.