In our area petrol prices regularly top 136p per litre. Diesel comes out higher as 146p per litre although you do get more miles to the pound. The electric car is out of reach for most pockets. So what can you do for cheaper motoring? Perhaps you should take the up my home brew challenge. No, not beer making but fuel refining! How does 20p a litre sound?

Since July 2007 those nice people at HM Revenue & Customs allow you to produce 2500 litres a year of your very own biodiesel without having to pay a penny of duty. All you need to do is notify them and apply to be registered as an ‘exempt producer’. You’re not allowed to sell it on so don’t get ideas about aiming for Shell’s or BP’s profits (£4.9 billion and £3.2 billion respectively for the second quarter this year).

So what do you need to set yourself up as a mini refinery?

The equipment can be bought as a set for around £700. BioBuddy is a popular choice. This all-in-one device makes the processing simple and tidy.

You can of course bodge some equipment together using the best of British ingenuity.

You have the equipment; you just need old, used cooking oil from your local chippy or hotel. It’s a win-win situation for you, the shop and the environment.  There are a couple of caveats; firstly you need to be prepared for the risk of fires: after all this is a flammable chemical you are making. Secondly, producing home brew biodiesel does take longer than popping to your local petrol station (although with the queues I see in my local area, that’s debatable).

On the BBC’s ‘You and Yours’ consumer program, Dan Purkis, a consultant engineer, explained why he delved into refining his own fuel. ‘It’s interesting, fun and it reduces my impact on the environment. When I looked at my lifestyle I realised that fuel was the greatest energy use in my life’. It certainly is, since this Aberdeen chap runs 4x4s. He had the DIY knack to make his own facility using salvaged and second hand parts.

He uses vegetable oil collected from a local hotel which would have been disposed of at cost to the business and the environment.

What does the process involve?

1. Sieve to remove batter fragments and other detritus

2. Heat the oil

3. Mix with chemicals (methanol and sodium hydroxide)

4. Wash the fuel

5. Dry the fuel (to remove any water)

6. Filter through a 5 micron mesh

Easy as that?

Proponents of home brewing are keen to downplay the downsides but to make this a balanced discussion the cons have to me mentioned too. Biodiesel is more viscous than normal diesel and this can put extra strain on the fuel injector. If it breaks down you’re looking at a bill for over £1000. You can reduce the risk by mixing the fuels or by installing a heater next to the fuel line. If your vehicle is still within its warranty period, check with the manufacturer to make sure you will still be covered.

Using methanol and sodium hydroxide require care as both are hazardous to human health and don’t benefit the environment if they enter the watercourses.

Do I Need to Convert my Car?

If you want your car to run on standard vegetable oil instead of your own biodiesel then you do need to make a few alterations. A company called Veg Oil Motoring has championed this technique for years and has built up a successful business based around it. They were the first to drive from Land’s End to John O’Groats only using vegetable oil.

Veg Oil Motoring has championed this technology in the UK, and especially Wales, over the last 5 years. We were the first to drive from Lands End to John O’ Groats on pure vegetable oil.

There’s plenty of mileage (excuse the pun) in considering a change to your forecourt fuel. Long term there is money to be saved if you are willing to put the time and effort in. For an average driver travelling 12,000 miles per year, you would have recouped your outlay and regular associated costs within around 12 months and then your fantastic savings will begin.

Guest blogger, Greg Coltman, writes prolifically for motoring and transport blogs and specialises in innovations with the motor industry.