Sunday, April 23, 2006

DIY Vegetarian Electricity

The day has finally arrived!

Following a few test runs, my Lister engine and generator was now ready to be run on vegetable oil.

The whole point of this project is to make heat and power from renewable fuels, and to reduce my consumption of fossil fuels. The Lister engine is an ideal way of converting waste vegetable oil into a viable domestic energy source.

I managed to pick up a scrap exhaust pipe from the skip at my local exhaust centre, and that was fitted in a somewhat temporary fashion - but worked very well in taking the majority of the noise out of the exhaust note.

A coil of microbore copper tubing was wound around the hot exhaust pipe - where it emerges from the cylinder head, and this was connected up between the fuel tank and fuel filter. The 16 turns of tubing acts as a fuel pre-heater and it warms up the vegetable oil sufficiently for it to flow like diesel. The Lister doesn't care what fuel it runs on, but I do!

Once heated up, the Lister runs normally on the warmed vegetable oil, without missing a beat. A temporary water cooling tank has been rigged up on the right handside of the engine. Eventually this will be replaced with a heat exchanger that will provide hot water an contribute to the central heating system - thus allowing me to burn less gas next winter.

The output from the alternator will be connected to a battery bank and inverter system that will supply power to the house.

This allows the engine to be run efficiently at full power for about 5 hours per day, using just about a gallon of waste vegetable oil, and recharging the battery bank. The engine is capable of generating 3kW of electricity - enough to power a kettle, but most of the time, my house only needs about 1/20th of this. Charging the batteries during morning and the early part of the afternoon, when houshold usage is low, will then allow us to run off inverted battery power for the remainder of the day.

The key to most renewable systems is the ability to store energy from times of plenty, and then trickle it out at the rate at which you need it. I suppose the same can be said for solar heating systems and rain water collection - it's just a case of storage, whereas grid systems lead you to believe that you can take as much as you want, whenever you want and it will always be available.

There are still several tasks to perform on this project. Firstly I need to build a new shed around the engine. I hope to use straw bale construction for this. The straw bales will not only attenuate a lot of the general engine noise, but will also offer good heat insulation from the elements.

Straw bales are readily available, quick to build with renewable resource and can be constructed without using excessive amounts of other building materials - such as cement and concrete blocks. The outside of the shed will be clad in shiplap boards - so that it looks like any other garden shed.

This building will house the whole of my renewable energy system, engine, inverter, batteries and veg oil filtering tanks. On the roof will be my solar water heater, which can also be used for pre-heating veg oil or warming the engine on cold but bright mornings.

Connected to the house by just two heating pipes and a power cable, the whole system can be isolated, when not in use, and the house returned to conventional heat and power if needed.

This is pioneering stuff, widely forgotten since the advent of grid power in the 1950s, and not everybody appreciates the long term benefits of no longer being wholly reliant on grid power.

Recently, the friend of a neighbour, came around to see the engine. Now in his 70's, he told me how his uncle had a Lister engine like my one, back in the 30s, and how, as a young boy, he was allowed to start it. He then explained how in the 1950s, he built a bungalow on a plot of land, and ran a homemade generator set, until eventually the house was connected to the grid. He told me he used the radiator from an Austin 7, mounted on his inside kitchen wall, to warm the house from the engine heat - remember this was before central heating was cheap and commonplace. It just goes to show what goes around, comes around!


clair said...

I think all this stuff that you're doing is fantastic...I can't wait to get out of rented accomadation and into my own house so that I can put more of these kind of things into practcie.

Ken Boak said...


I can understand the frustrations of being in a rented property. I was lucky I got on the property ladder back in '88, but it was tough in the early 90s.

A lot of the easy stuff can be done in any property, and it is simple to fit low energy bulbs and be conservative about your use of electricity and gas.

The key is understanding how much you are consuming, and then make appropriate reductions. Power, gas, water and rubbish can all be reduced with a little effort.

If you are in the UK and want to contact me directly for advice, I can be reached at

chris said...

fantastic site.
Sadly we are complete dummies when it comes to engineering.
You might be able to get your special energy saving bulbs from IKEA as they seem to have a huge range of them.
I can remember my mum taking newspaper in a shopping bag to buy her potatoes at the grocer. He only supplied bags if asked and they were always paper.When we got our first plastic carrier bag in about 1968,I was allowed to borrow it to run an errand and then it went back in mums shopping bag for emergencies.

Nick H said...

Hi Ken, I had been pondering why CFL bulbs were not recommended for use with invertors, they seem to work ok off the small one I have in the car after all. However, reading your comment Re. dimmer switches in the previous post, I have come to the conclusion that the high harmonic content of the supply must somehow disagree with the electronic ballast circuitry and were I to do an endurance test, their life would probably be similarly shortened.

I guess that means you are unfortunately stuck with inefficient incandescents for your lighting with the veg gen system.

BTW do you think you will have any noise and vibration problems with the system given yout urban location?

Ken Boak said...

Chris and Nick,

Thankyou for your interest.

Regarding CFL lamps with inverters - it depends on whether the inverter is the cheaper "modified sine wave" type or the more expensive pure sinewave type. The MSW type produces an output waveform that is only a crude approximation to a sinewave and thus has a very high harmonic content. If you present a pure 50Hz sinewave to the CFL, this is no different to grid power, so the life should be unaffected.

Regarding noise and vibration - both obvious isues when running this type of machine in a suburban setting. The engine can be effectively silenced using an automotive exhaust system, with an extra large expansion box - used to house the exhaust heat exchanger. The higher frequency "rattling" noises from the cam shaft, valve gear and the hum from the toothed belt drive can be effectively absorbed using an acounstic enclosure around the engine. I am working towards a wooden shed, lined with straw bales and internally clad in panels of underfloor felt insulation.

Vibration is also a key issue. Ideally these engines should be bolted down to a big concrete block sized abour 600x 1200 x 300mm thick. This should be isolated from the concrete shed base if at all possible, otherwise the base will act as a sounding board. Whilst my current set-up is far from ideal, it does show what is achievable.

Anonymous said...

Hi Ken, I have been reading thru your blog, and really enjoyed this particular entry. As I'm planning my she dlayout, I'm really interested in the bit about isolating the engine from the ground.

Ken Boak said...


Please email me at ken.boak@gmail.comfor more information


grahamprie said...

I think you've got the right approach, but what you're doing would be totally uneconomical if you had to pay 'high street' prices. What would the Lister cost new?

There are a couple of points, though - firstly, I don't like the colour of the light from low energy bulbs - they make everything look old and faded.

Secondly, although I'm sure the claimed wattage ratings are correct, as far as power consumption goes, the relationship between the lumens isn't - I find I need to use at least twice as many watts of low energy bulbs as the ratings would suggest to get the same light levels. It's still a saving, but not as much as they claim.

I also find them annoyingly slow to turn on, so for a quick trip to the loo, I manage without any light...

Finally, don't even think of switching your satellite TV receiver off at the wall - the reason for the consumption in standby is to keep the outside 'LNB' unit warm and dry.

You'll not be happy if you have to replace it every year or so - they cost a lot more than the saved electricity.