According to the website GreenFuels.org, "the major disadvantage of biodiesel is high production costs.
Studies conducted when agricultural commodity prices were much lower than at present and petroleum prices were in the range of
US$18 to $20 per barrel concluded that petroleum must rise to over US$40-$50 per barrel to make biodiesel production viable without
a subsidy.
One study suggested that the production of subsidized biofuels can only be justified if a high premium is put on the environmental
cost of the alternatives. Also highlighted was the very poor energy accounting of biofuel production considering the energy consumed
in the manufacture of fertilizers and pesticides to produce the crops plus energy used in cultivating, harvesting, transporting and
processing of the crop.
One additional concern is the environmental impacts of increased fertilizer and pesticide usage to increase oilseed production for
use in manufacturing biodiesel.
Biodiesel has a higher viscosity than conventional diesel and therefore becomes less useful at lower temperatures.
This limits its use in Canada, the northern U.S. and much of Europe. In these areas, biodiesel is marketed as an additive
in a five to ten percent blend with conventional diesel fuel."
