Well I've read this with a lot of interest, I've been running all the family cars we've had since 1998 in Biodiesel, so far covering around 150,000 miles in total.
I used to fill in my tax return form to declare it too, until my tax office returned the form saying "we are no longer taxing people who produce less than 2500 litres a year"...RESULT!!!
I think there have been a lot of myths and legends that have been perpetuated over the years about biodiesel, most of them can be eventually traced back to either ignorance on the owners part or very poorly produced biodiesel.
The most often spouted ones are:
It turns to white jelly in your fuel filter and It causes all the dirt in your fuel tank to enter the filter....etc etc etc
If Biodiesel has turned to a white jelly in your fuel filter, it was not washed and filtered properly, the white jelly is soap that hasnt been removed properly if at all.
Biodiesel is a fantastic cleaner, and is great stuff to use as a biodegradable alternative to 3 in 1 oil etc, and as a result it cleans the styrene and wax based deposits that normal dino diesel leaves on the inside of a fuel tank over the years. This is normally taken care of by changing the fuel filter once at around the 500 mile mark after changing over to 50% bio, future fuel fliter changes after that should only need to be done exactly the same as the manufacturers recommend.
Well produced bio is actually better for most diesel engines (lucas diesel pumps being the exception!) as when the sulphur was removed from forecourt diesel, they removed an important part of the lubricating properties of dino diesel, as a result top ends of modern diesel engines running sulphur free fuel wear at a higher rate than thier predecessors, but biodiesel is actually as good at lubricating if not better than dino diesel.
I am lucky in that a friend of mine owns a pub/restuarant and has to pay to get used cooking oil taken away (costs him around £30 a week!)
Every couple of weeks I now take 200 litres off him so both of us are happy, also means 200 litres of oil get recycled.
The costs saved are tremendous even allowing for the methanol and sodium hydroxide
I think it works out at around 12p a litre to make (being honest I think its less but havent stopped to work it out yet!)
Recently after filling the tank of our Xantia to the absolute brim from empty I did work out that it cost a shade under £10 to fill up.
As for the shenanagans going on with deforrestation to grow biofuels, it really hacks me off, but the oil obtained from palm oil is unusable as biofuel in wintertime over here in the UK, it would be solid at temps below 5-9 degrees C!!
A much better alternative would be
Jatropha curcas this plant grows like a weed, favours arrid areas so wouldnt drain precious water reserves, and would also enable third world coutries to benefit from renewable energy sources.
As per normal though our energy requirements are being taken care of by greed driven opportunists, rather than people caring for the environment.
Blimey I'll shut up because I've just realised I've written a huge post on an old topic!!!...but its something I'm pretty enthusiastic about