Introduction
These are fuels from recently dead biological matter,
examples being vegetable oil, gas from landfill sites,
and in a historical context, tallow for candles.
There have been recent reports of vegetable oil production
involving damaging and irresponsible agricultural methods.
There are however many ways of making and using biofuels which
are not harmful, and may in some cases be beneficial, for example
the collection of methane from waste tips.
This is produced by the action of naturally occurring anaerobic bacteria,
and is a potent greenhouse gas, but is also a valuable fuel which can be
used for heating and power generation.
The main environmental advantage of Biodiesel is that it is
carbon neutral. So using 100% Biodiesel in your vehicle means you are
not adding to the global warming crisis. Biodiesel does not add any carbon
because it uses the amount of carbon which naturally circulates between the
atmosphere and the biosphere (by photosynthesis).
Conventional fossil diesel however, does add to the overall level
of carbon by extracting carbon deposited in the geosphere (mineral deposits)
and releasing it into the atmosphere.
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Waste vegetable oil
Cooking oil is a material which cannot be used indefinitely,
and must be disposed of regularly and replaced.
These can be converted by a straightforward process into diesel fuel,
and a local business is doing this and running not only its fleet of
vehicles on biodiesel, but also the generator which powers the factory,
enabling it to be independent of the mains electricity supply.
Food waste
Food waste containing cellulose, starch or sugar can be fermented to
produce an alcohol-rich liquid which may then be distilled to give ethanol.
A slightly-modified car engine can use this as fuel, and an unmodified engine
can run on a petrol / bioethanol mixture.
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We've also heard of a scheme running locally to redistribute commercially
produced biodiesel. This has been set up by a member of the Wharfedale
Friends of the Earth group and is called the 'Wharfedale Biodiesel Group'.
Their Yahoo group is
here.
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