By Barney Smith

When I wrote recently about Biofuels in rather general terms. (See Greenbarrel of 16 July), my interest was aroused by an aspect of Biofuels, namely Biodiesel, which is usually seen as an element in renewables. But, if truth were told, its importance lies more in its decarbonisation attributes than in the claims many would make for its sustainable or renewable status. And for the future, much depends on how the relative costs of petroleum fuels and biodiesel feedstocks move.

As its name implies, Biodiesel is an alternative fuel, similar to conventional diesel, derived from raw vegetable oil, but also from waste cooking oil, as well as animal oil/fats and tallow. The largest possible source of suitable oil comes from oil crops such as rapeseed, palm or soybean, with rapeseed presenting the greatest potential for biodiesel production in the UK. Though oil straight from the agricultural industry represents the greatest source in theory, it is not commercially attractive simply because the raw vegetable oil is not competitive in price terms. After the cost of converting it to biodiesel has been added on it is simply too expensive to compete with fossil diesel.

There is also the criticism that the vegetable component from plants eg corn or soya, has been diverted to provide a “greener” fuel for cars belonging to the rich, rather being used to provide food for the poor. The outcome is arguably to make food more expensive for the poor. Any rise in wholesale grain prices would thus “validate” this view.

Be that as it may, at present most biodiesel is produced from waste oil sourced from restaurants, chip shops, industrial food producers such as Birdseye etc. Waste oil can often be sourced for free or sourced already treated for a small price and the result is that the price of Biodiesel produced from waste oil becomes competitive with the price of conventional or “fossil” diesel even after a calculation of the energy costs of refining and transporting the finished product.

As a result, a number of companies, mostly privately owned, collect used cooking oil, both animal and vegetable, supervise the refining and then deliver Biodiesel to their customers. These companies include Proper Oils a London based company, Beesley Fuels, which is based in Birmingham, Veolia and Biopower, as well as Olleco, the renewables arm of ABP Food Group, which has grown to become the UK’s leading supplier of premium cooking oils and fats and collector of used cooking oil and food waste.

In decarbonisation terms Biodiesel is, or can be promoted as, “Carbon Neutral”. This means that the fuel produces no net output of carbon in the form of carbon dioxide (CO2). When the oil crop grows it absorbs the same amount of CO2 as is released when the fuel is combusted, though when used cooking oil is converted into greener diesel, the energy cost of conversion has to be calculated against the environmental advantages of the resulting fuel. Biodiesel also offers some practical advantages: it is rapidly biodegradable and completely non-toxic, so spillages represent far less of a risk than fossil diesel spillages. Additionally, it has a higher flash point than fossil diesel and so is safer in the event of a crash.