Biofuels: past, present and future?

There’s been lots of talk about biofuels and how they could help countries move away from oil and gas. So, just what is a biofuel.

The original biofuel is wood, used for millions of years, it’s a firm favourite for people to use. Around 90% of it is locally harvested and 38% of the planets population rely on it. The pollution from this source kills approx. 1,5 million per year. New wood burning (biomass) power stations are being proposed with 4 going through the planning system in Scotland just now. Where the extra millions of tonnes of wood these will require is not clear.

Believe it or not, methane from sewage and domestic waste has been in use for thousands of years. New anaerobic digesters (which convert food waste into methane gas and organic fertiliser) are in use in China and India to provide about 30 million homes with heating and cooking gas supply. It has the potential to power vehicles. Waste however is not an unlimited resource and efforts to reduce waste would make this redundant. There are proposals to use anaerobic digesters by a couple of Councils in Scotland but they require waste to continue to be created which defeats the purpose of a zero waste strategy being pursued by the Scottish Executive.

Cooking Oil which is recycled from restaurants, the chippie and other fast food joints is reprocessed into vehicle fuel. There’s not a lot of it around though to act as a proper replacement fuel for cars.

Ethanol and biodiesel are two different sources but usually lumped together. Ethanol is made from sugars or starch crops like corn, sugar cane, wheat, sugar beet and barley. Biodiesel is made from oil crops such as soybean, rapeseed, oil palm. Both considered as ‘first generation’ biofuels and many countries are blending both in their transport fuel supply.

Liquid biofuel comes from wood and grass and is still in research – second generation. High yield non-food crops that can be grown on “marginal” land. However, it could gobble up grazing land, wilderness or become mainstream crops.

Agricultural waste, like the stuff immediately above made from the carbon in cellulose and at the research stage. Made from stuff like corn stover – the left over bits not used by us – could be a useful, local source. But, straw “waste” has other uses that would require replacement by other materials.

Algae: either seaweed or pond scum. Can be grown in tanks or in the sea and doesn’t require agricultural land. A long way off and many issues to be investigated before they could become a reality.