E10 Petrol - Its Effects on You, the Environment, and Your Classic Car.

E10 is an issue that has caused an incredible amount of hearsay comments, myths, and untruths. So let's take an objective look at E10's impacts.

1w ago

First of all, what does E10 mean? Well, petrol classification in the UK is the product of history and is a little bit messier than it needs to be. On most pumps, there are two grades of petrol, Premium Unleaded and Super Unleaded, or something along those lines. The unleaded part we can ignore immediately, as UK petrol has been lead-free for decades, but Premium is, confusingly, the standard, cheaper grade of petrol available, at an octane rating of 95. Super or Supreme is the more expensive petrol, and that can vary between 97 and 99 octane, depending on where you go. These octane numbers don’t particularly matter to us in this context, but up until September, both these grades would have had a little symbol above, showing they were E5, meaning the oil companies were permitted to make 5% of this ethanol. Now though, the ethanol content has gone up to 10%, or E10 in premium unleaded. Super unleaded is remaining at E5 for now, as a ‘protection grade’, as there are many cars that shouldn’t be filled with higher concentrations of ethanol, because this increase has a number of possible effects on you, your car, the economy, and the environment.

The first thing we need to understand is what difference ethanol makes to the petrol itself. By adding ethanol, you change the chemical make-up of the fuel, and therefore the way it burns. Pure ethanol contains about a third less chemical energy than pure petrol does, meaning that it’s less efficient and that cars must run richer on it in order to retain the same power output. In simple terms, you have to burn more of it, and that will increase your fuel usage.

But there are some significant performance advantages to using ethanol, despite having to burn more of it. Ethanol is much more resistant to detonation, allowing cars to use higher compression ratios and more advanced ignition timing to make more power. That’s why racing series all around the world swear by ethanol. When pure performance is the be-all and end-all, ethanol is just better. That’s not just why it’s used in racing, but also in modified cars where it’s available.

But what does this change actually mean for motorists? Well according to the government, all cars built after 2011 are compatible with E10, but that’s rubbish. A number of MG dealers have come out and said that they don’t recommend the use of E10 in their cars up to 2015, meaning that a six-year-old car apparently cannot use the fuel the government is mandating. Additionally, the government’s compatibility checker is patchy. Many of the statements given to the government by manufacturers are vague. For example, Peugeot says that all their petrol cars built after 1st January 2000 are compatible with E10 fuel. What changed on 1st January 2000? They didn’t introduce any models on New Year’s Day, so where is the line? Tell us which models built when are and aren’t compatible. It surely can’t be that difficult. As a result, non-car people are none the wiser. Those with a 1998 Peugeot of some kind will be rocking about thinking that they need to pay about 10p a litre more for fuel now. And that’s just not the case. Similarly, the page for Rover simply states that the company does not exist anymore. As a result, there is no information available, and Rover drivers should use E5, and pay 10p a litre more. Now, I understand why the page says this, but the government owes it to the people they represent to provide the information on an issue they have caused. If we look at the Land Rover page, we see that all models since 1996 are E10 friendly, meaning by extension that a good 90% of Rovers built since then must also be compatible, as being part of the same company at the time, they used very similar fuel systems and many of the same engines. In fact, some individuals that worked at Rover’s Powertrain division have confirmed that late Rovers are absolutely fine on E10. But as far as the wider public are concerned, Rovers can’t run on E10. This perceived fact is being picked up by so-called ‘journalists’, who are writing doom-mongering articles based on information that’s just plain incorrect.

Another general problem with the switch are those who run an older car for financial reasons. There are thousands of people driving cars around 15 to 20 years old who do so because they have to. And if their cars can’t run on E10, then they are being forced to fork out over £100 a year extra on average for a higher grade of fuel, and that makes a big difference to those living week to week. As these cars make up the majority of those who will be most affected by E10, the argument can be made that it’s essentially a tax on the poor.

A final general issue is E5 availability. For those who own cars that aren’t E10 compatible, they should be filling up with E5, but super unleaded isn’t available at many fuel stations around the country, and in more rural areas, the vast majority of petrol stations only stock lower octane fuel, now mandated to be E10, so some people have to fill with E10, even if it could be having negative effects on their vehicles.

But the main reason behind the increase in ethanol content is the positive environmental impact. It’s upon this issue that 95% of the arguments for the use of ethanol come from, and as such it’s vital that this is a genuine, worthwhile positive impact.

According to government figures, the switch from E5 to E10 could reduce the UK’s carbon dioxide emissions by 750,000 tonnes per year, the equivalent of taking 350,000 cars off the road. And immediately, that sounds like a worthwhile change. Anything that can reduce our carbon footprint is a good thing, especially as that’s compounded by better, more efficient public transport links and more people being able to work from home.

The main point for ethanol is that it’s a biofuel, something that can be grown, and therefore it’s renewable, covering one of the long-term questions over petrol availability. But there’s always a cost. Growing crops to ferment into ethanol takes up space. Lots of space. The largest corn producer in the world is the United States, and about 40% of all the corn they grow goes into the production of ethanol. And in a country like the US, with lots of empty, fertile land, that’s acceptable, but there’s an issue here for smaller countries or those with harsher conditions and terrain. Where’s the line between fuel production and food production? In fact, the US has had E10 for a number of years, and already 8.8% of US farmland is dedicated to the production of ethanol. 8.8% of farmland for 10% of petrol. What that encourages is higher corn prices, and therefore two things, higher food prices and more natural land being converted to farmland. So as ethanol becomes a necessity in petrol, the strain on the farming industry will only increase, but with that, we see some more pressing impacts. The whole point of using ethanol is that it is more environmentally friendly in one way or another, but when it comes to pure energy, that argument begins to fall flat. A study by David Pimentel shows that production, from the seed to one litre of pure ethanol, consumes around 6,600 kcal. That litre only contains about 5,100 kcal. This process is energy negative, and when we bear in mind that in order to live we have to eat, it suddenly starts to look questionable why we’re putting all this effort and land into producing something we can, at least at the moment, get from the ground. When we look at water usage, for example, something else we absolutely need to survive, the production of biofuels requires 65 times more water than crude oil does.

There are alternatives to corn though. South America is the continent that uses the most ethanol in its petrol, and they use sugar cane to produce it, which is energy positive. But again, we come back to farmland. In that chase to produce more and more ethanol, the rainforest is being destroyed. We cannot get around that one fundamental of using farming to produce fuels. In addition, the destruction of habitats isn’t just harmful to wildlife, but to us as well. Just looking at emissions, the effects of the loss of forested areas will take 20 years to be recouped by the reduction in vehicle emissions. And surely by that point, vehicles should be moving away from fossil fuels anyway? The strategy from governments, therefore, seems a bit dead-ended.

What’s better for biofuels than long term availability though, is sustainability. As our engines burn fuel, they produce gases that are harmful to us human beings, like carbon dioxide. Potentially the biggest advantage for biofuels, therefore, is that they address this imbalance. As we all know, plants absorb carbon dioxide, potentially allowing us, in the long term, to offset one of the biggest disadvantages of burning fuel. Put that alongside the cleaner burning of ethanol, and there is a carbon-based case for using ethanol, but combine it with the reality of farming, our human needs, and what the future looks like, and it begins to look decidedly patchy.

Now we’ve looked at E10’s impact on the average consumer and on the environment, we can discuss what we’re all really here for – the mechanical impact on our beloved cars.

When it comes to people worrying about E10 potentially causing the entire classic car world to come crashing down, it’s actually something we’ve seen before. When leaded fuel was phased out about 30 years ago, people went around screaming about how it was going to destroy engines and fuel systems, especially the valve seats in the cylinder head, but time has shown that the worries were all a bit over the top. Sure, ethanol is a different issue with different potential issues, but the UK is rather behind when it comes to this. There are whole continents that run on much more ethanol than E10, and to give just a few major examples, the United States, Australia, and the majority of the European Union all already have at least E10. In fact, the introduction of renewable fuels has been on the minds of scientists and governments for decades, and if we go all the back to 1981, 40 years ago, we can see a study on the mechanical impacts of ethanol fuels. The US Department of Energy sponsored a study that tested a number of identical engines with a range of different fuels, but the ones we’re interested in are straight petrol, E0, E10, and pure ethanol, E100, and through this we can see the full range of ethanol’s effects. The engines were ran at high revs and, more importantly, high load for 20 hours, then the engines were disassembled and studied. They found that the difference in wear within the engine, on pistons, and valves for example, is negligible, but they found that the oil in the engines running ethanol contained ever so slightly less metal, but again, very small differences. What they also found was that E100 has a significant cleaning effect when it comes to avoiding sludge build-up, something that lots of expensive fuels promise to do, but with a small amount of ethanol in the fuel, as we’re seeing with E10, that advantage is minimized. Their final interesting point was that the engine oil contained trace amounts more water when running on ethanol than it did on petrol, bringing us on to a much bigger issue.

This is the one people are worrying about, the fuel systems and fuel hoses in classic cars. If you remember back to chemistry at school, you’ll know that ethanol is a solvent, meaning it degrades certain materials, such as rubber, much quicker than petrol does, and this causes a massive potential safety issue. If the gaskets in your carburettor or the rubber fuel hoses start to degrade and leak, that’s not good news, especially in an engine bay. For example, the carburettor on an Austin A-Series engine sits directly above the exhaust manifold, so if the fuel feed hose or the carburettor itself starts leaking, that’s a fire waiting to happen. If you increase the ethanol content in the fuel, those materials degrade quicker and the risk of fire increases. But apart from E10 there are two distinct problems. The first is that an awful lot of the rubber fuel hose on sale is of appalling quality. Frankly, regulation should be made much stiffer in this field as these are people’s lives at stake, but there is fuel hose out there, that even on E5, has started to crack within months, so if you are replacing fuel hoses, make sure they’re of the highest quality you can find.

Second of all is us. People. We’re inherently stupid. And as classic car enthusiasts we’re driving around in cars with rubber componentry that is potentially decades old. 99% of motorists have just about managed to get it into their heads that rubber ages. We understand that tyres, even if not used, eventually get old, go hard, and crack. As a result, we change them. So, why’s it so difficult for people to change their fuel hoses? After all, my little Metro should have had a couple of sets of fuel hoses by this stage, and I’m pleased to confirm that the hoses look in perfect condition, because I check them, just as you should. So please, for your own safety, check the condition of your fuel hoses. If you need new ones, get new ones. But it might save your life, and it might save your car.

We, as a community, need to begin to take this seriously. There will always be idiots out there that don’t care about the condition of their cars, but this matters not just for your safety, but for the future of our hobby. We’re living in an age where new technologies are coming in and replacing the internal combustion engine, and most governments around the world are happy to allow classic cars to exist, as they should. But if you’re negligent, and one day your MG B or your Volkswagen Transporter catches fire, that paints a bad picture for old cars in the heads of those that use cars merely as transport. Some incidents can’t be foreseen, but don’t let a lack of maintenance make us all look bad.

Sorry for getting off-topic, but the main practical, vehicle based, complaint regarding E10 is the degradation of fuel systems, and though some materials used to produce fuel tanks, or tiny components in the fuel systems may be difficult to get up to E10 standards, just make sure it isn’t something as stupid as fuel hoses.

Our conclusion, unfortunately, is that all the positive arguments for the use of ethanol just don’t translate into a worthy alternative. It’s less efficient and takes up a ridiculous amount of land, costing consumers more money both in fuel and food. It has the opportunity to damage parts of your fuel system, though not as dramatically as some people fear, and its environmental credentials are questionable when we consider that within 20 years, the majority of everyday, run of the mill cars should be electric. In fact, the existence of the electric car makes ethanol look worse, thanks to its habitat damage. And at this point, as petrol-powered cars are beginning to become legacy products, is such an upheaval even worth the political will?

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Comments (5)

  • Great article that simplifies some of the facts/mistruths.

    I appreciate the issue around climate change but ICE’s are only a small part of the contribution, industry/farming etc etc also impacts but the real problem is that there are twice as many people (consumers) on the planet than 50 years ago as as such thats the climate change issue. Forcing E10 is a micro solution to a major problem.

    Governments should start at the biggest issue and work down rather than the small ones and work up.

      13 days ago
  • What a brilliant article. This is something that has concerned me as someone who runs classics on a daily basis. Last week I was forced to use E10 in my 1994 Rover 220GSi. It ran ok, was a bit more rorty but it felt down on power and overall a bit rough. I put half a tank of E5 in the next day to equal it out and it ran really nicely, so it isn't a disaster if you use the car regularly or just need to get home. But I do absolutely feel your fuel line argument is very pertinent. Our military vehicle running friends found the fuel componentry on their WW2 trucks was melted completely by this stuff after just a short time. I do think fuel injected cars can handle it better, but I always go for E5 where I can. It was odd, in the middle of the fuel crisis I turned up in the Rover at the fuel station which was empty. All the E5 pumps were dry, yet all the E10 was full. It seems everyone is just going for it, which means there is now half the fuel there was...

      13 days ago
  • Its mad, if your car only runs on 98+ octane (such as some jdm performance cars) - the uk government still say e10 is safe to use.......even though you couldn't use regular 95 before without your car burning through it & producing white smoke. With an even lower octane rating I cant imagine its healthy without a flex tune

      13 days ago
  • If you leave a car parked with E10 for 18 months, it turns into varnish in the carb, and your car car gets a urinary tract infection.

      7 days ago
  • Good article, a couple of thoughts. On the Government information I think the government is doing its best on this and there is far more information available on this change than there was when we switched to unleaded, Incidentally Ferrari only officially confirmed its older cars were fine on unleaded in 2010 nearly 20 years after the switch (the fact that they suddenly realised they could monetise the older models was probably not coincidental).

    Also your point on fuel hoses is totally correct but there is a specific issue with classic cars that many sit for long periods of time with the fuel in the tanks degrading which with ethanol (even E5) in the fuel can lead to more water in the fuel systems. I've used an ethanol protection in my fuel tank for 10 years plus. While that is not a practical solution for daily driven cars it is something to be considered for classics not in regular (daily) use.

      13 days ago