DaveMcT said:

The UK numbers for vegetable oils back in year 2000 were something like 2 million tons per year consumed as food with a proportion used for frying. If we suppose that 1/3 might be available as waste cooking oil that gives lets sat 700,000 tones if we collect it and refine it. To that we need to add 150,000 tones of methanol (maybe a bit less) which comes from natural gas. The left over glycerol (about 70,000 tons) could be burnt in power generation diesels.

To put all that in context, UK used 17 million tons of diesel alone. Petrol was probably about the same again (I can't remember).

That begs the question why bother with all the faff for biodiesel when cooking oil can be added to ordinary diesel at up to 20% without any problems for engines. The only reason we did not do that was Germany demanding that biodiesel must not contain any glycerol. It's not clear where that came from but probably a stick to beat the whole idea out of existence.

Biodiesel (methyl ester) by the way is an excellent fuel but the many costs do not outweigh the benefits. Not least the diversion of agricultural land away from food production and pushing up the costs of such as rape seed oil. It also led to oil palm plantation in places like Burma which replaced virgin rain forests.

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chris3234 said:

One little note veg oil is of not use on modern common rail diesel's especially those with dpfs


Older mechanical injection diesel's are happy on it all day

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