The advantages of biodiesel far outweigh the
disadvantages, although there are a few. Biodiesel has long been
shown to reduce all regulated emissions, with the exception of
nitrous oxide (NOx) emissions, which are a contributing factor
in the localized formation of smog and ozone. Few studies suggest
a slight increase in nitrous oxide emissions and varies widely
based upon the type engine and type of biodiesel used. Older engines
may be responsible for higher nitrous oxide emissions as well.
Nitrous oxide emission increases range from 1-15%. Nitrous oxide
emissions can be reduces through additives in the biodiesel. Emissions
can also be reduced through the lowering of the combustion temperature
of the fuel, which will decrease nitrous oxide emissions to, or
below, the current level of NOx emissions. One other issue with
biodiesel is the effect extreme cold weather. Cold temperatures
cause wax crystals to form which plug fuel filters. Different derivatives
of biodiesel result in different temperature thresholds, for example,
soy biodiesel can be used down to –1C, and cooking oil biodiesel
can be used down to –9-12C. Standard diesel goes down to –29C.
In order to compensate for cold temperatures a number of things
can be done. Additives can be added to the fuel, electrical elements
that heat the fuel back up, fuel tank heaters, and coolant operated
fuel heaters. Beside these minor issues biodiesel is easily compatible
with current fuel infrastructure and diesel engines.
