LPG: It's lean, green and cheaper too
Four months ago Miles Brignall converted his car to run on LPG. It cost £2,000 but saves him cash on every trip. He looks at the whole process and assesses if it's worth it. Do you look back with nostalgia to a time when you could fill up your car for under £30? I don't. Because £30 is all I pay to fill up my Toyota estate when everyone else is paying at least £60.
For the past few months, we have been running our family car on liquefied petroleum gas (LPG), or autogas as it is increasingly known, and as a result have slashed its fuel bills by almost 40%. Even on our relatively low mileage we are on target to save around £750 this year – while at the same time pumping out less harmful emissions into the atmosphere. The cost of converting to LPG was just over £2,000, but if you do relatively high mileage, and are fed up with paying £70 a week to drive to work, my conclusion is that it's worth it.
I first looked into LPG back in April, when petrol prices hit 139p a litre and LPG was just 75p. I was intrigued by both the money and environmental claims of the LPG lobby, and decided to road-test them.
LPG car conversion experts Prins, and Autogas, the biggest supplier of LPG to the UK's filling sites, agreed to convert our car at their cost while I would report back, warts and all, how I got on.
The car is our 2006 Toyota Avensis estate with a 1.8 litre petrol engine. It had 72,000 miles on the clock, and we're hoping to run it for a further five or six years, by which time the mileage will be around 150,000.
We are not typical LPG convertees in that we don't use our car to commute but we do a reasonable mileage – around 12,000-14,000 a year – from a typical family a mix of local drop-offs and longer runs.
The conversion was carried out at the Prins UK headquarters in Southampton and it took around four days. It would have cost £1,500 for the system. Most non-German cars – including ours – require Valvecare, which protects the valve seats in the engine, and adds £200 to the conversion. The total cost for our car would have been £2,040 including VAT.
It should be noted that we had a few teething problems at the start, and it took our local Prins dealer, Herts Autogas in Knebworth, to get the system running to maximum efficiency, but this is quite common. Generally, a couple of thousand miles after installation, you have to go back for a free calibration check to ensure the system's running properly.
What was done to the car?
The most obvious change to the car takes place in the boot. Where our spare tyre once sat, there is now a gas tank which holds around 10 gallons of LPG. It sits under the flooring, so there is no loss of boot area. We no longer carry a spare but have a tyre repair gas canister instead, plus a footpump.
Under the bonnet, the engine looks slightly different. There are four injectors which supply an extra liquid (ValveCare) and gas into the engine, as well as a few wires and an electronic box put neatly to one side of the engine. Inside the car the only sign is a control panel mounted on the dash which allows you to control the system and shows which fuel you are using and how much gas is in the tank.
How does it drive?
If you got into our car and started driving it, you wouldn't know you were driving a gas-powered car. The car always starts from cold on petrol. After you have been driving a mile or so, and the engine reaches around 45C, the car automatically, and seamlessly, switches to gas. The only sign is the lights changing on the control panel. In every other respect the car drives exactly as it would on petrol. If you run out of gas, the car automatically switches back to petrol, and, again, you wouldn't know it had happened except the system alerts you with a short buzz.
Because you drive a little way at the start of each journey on petrol, you will need to put a few pounds worth of petrol in the car each month. You can run the car on petrol by pushing the button on the control panel.
The all-important costs
Before the car was converted, it was achieving around 38 miles per gallon – depending on the journey type. Most converters say when you run on gas you will get 15%-20% fewer miles per gallon because gas has less energy in it than petrol – and so it has proved for us. After plenty of gas refills we calculate we are getting 30-31mpg on gas – a 20% reduction. The biggest disparity is on fast motorway runs. On slower roads and around town the gas reduction is closer to 15%. Prins says the average reduction is around 15%,but gas is almost half the price of petrol.
The key to making LPG work for you is to find a cheap local source. We have a local BP Autogas supplier selling LPG for 71.9p a litre. Petrol in our area is 135.9p a litre so the gas costs 53% of the petrol price, and we are getting the equivalent of 58mpg – better than we'd get on a diesel model of the same car.
We've found that the cost of LPG varies enormously – a few miles from our regular fill up, a forecourt is selling it for 81p/ litre. Yet some independent sites sell it for just 68p, while in Luxembourg this summer we paid just 53p. The UK average is around 75p.
If we were able to run purely on gas we would save around £820 a year – even on our low mileage. Once you factor in the extra costs – ValveCare fluid (£50 a year), plus the fact that we will probably spend £40 a year on petrol, (to cover the start-up period), the saving is more like £750. The only other factor is a service of the system every 20,000 miles, which at our local Prins agent will cost £120 plus VAT, although this can be reduced if the car has its standard service at the same time.
Our tank costs £30 to fill and gives us just over 300 miles between refills. Having converted, we are entitled to a £15 discount on our car tax.
Despite the perception that LPG is hard to find, we've had no problem filling up over the past few months, apart from in rural Wales. LPG is on sale at 1,400 sites in the UK – around half of them are traditional petrol stations.
Running on gas does require a bit of planning. You have to think about where you are going to fill up before you travel, and build a refill into your route, but it's easy. The UK LPG Association has a map showing each site. There's also an app for smartphone users that will direct you to the nearest supplier, and satnavs that highlight stations selling it. If you can't find gas on your route, you can, of course, run on petrol as normal, although paying 136p a litre again comes as rather a shock. One thing you never get used to is the loud hiss of gas as you disconnect the nozzle after filling the tank. Even though you know it's coming, it's still a surprise.
The environmental case
Besides the financial benefits, there is a strong case for moving over to gas on environmental grounds – a big motivation for us. "Well to wheel" analysis suggests LPG-fuelled vehicles generate 14% fewer CO2 emissions than petrol cars and 10% fewer that diesel vehicles. LPG is particularly clean-burning and produces fewer particulates – no big clouds of black smoke are emitted from our exhaust, as so often happens to older diesel cars.
LPG cars produce 50% fewer nitrogen oxides than petrol, and 20 times fewer than diesel.
Crucially, the UK has plenty of LPG, to the extent we export the excess, making it a more sustainable choice.
Autogas's Paul Oxford says companies that operate large fleets are increasingly looking to switch to gas as part of an environmental and corporate responsibility package, having recognised LPG's green credentials.
"There are green as well as financial benefits to running a fleet on gas," he says.
In recent months there has been a revival of interest in gas among the carmakers. Mazda is now offering its executive 6 model converted to run on gas as a no-cost option. Proton offers brand new models that are converted to run on gas. Several other makers, such as VW, offer their cars new and already converted – but only in mainland Europe.
So who should convert?
Our Prins conversion is considered to be one of the best on the market, but at £2,000 it would take us three years to recoup our costs. Worth doing if you are keeping the car for several years, and even more so if you do a bigger mileage than us.
If we drove 20,000 miles a year, we'd be in profit within 18 months.
However, a conversion makes even more sense if you run a less fuel-efficient car than ours. If your car does 25mpg on petrol and you lose 15% running on gas you are still getting 21mpg on gas – the price equivalent of around 40mpg.
Prins's Will Putter says the company has seen a big pickup in interest in LPG in recent months. "Drivers have realised that high petrol prices are here to stay and are looking for ways to bring down their fuel costs. Running your car on LPG is cheaper than petrol or diesel. The technology is proven and we find that once drivers give LPG a go they never go back."
He says it is important to use a quality kit and a tried and tested installer. "We get drivers coming to us who have installed cheaper systems and had problems. Once we have replaced it with one of ours, their car runs trouble free."
It's no surprise that many of those converting run SUVs or big executive cars that can now be bought cheaply as a result of high petrol prices. Reports of cars that cost £40,000 new being bought a few years later for £8,000 are common. With a conversion to gas, you get to drive a luxury car with the running costs of a Mondeo.
People looking to convert face a huge choice of installers, systems and prices. There are around 200 installers accredited by the LPG Association and a host of one-man-bands offering deals starting at £1,100. Look for a firm with a sound reputation, and beware anyone who says it can be done in a day. Our Prins system feels it will last the car's lifetime, although time will tell. When you think it can easily cost £2,000 to change a decent-sized car, the conversion cost starts to look good value.
The Guardian's LPG system was installed and paid for jointly by Prins and Autogas. We will report back on how the car is running, its costs and any problems in the next few months.
Source: The Guardian