The Many Pros and Cons of the Great E10 Switch – Part One



Whenever we cover a motoring issue on our blog, we like to give both sides a fair hearing. Whether it’s smart motorways, traffic reduction schemes or motoring tech, there’s always more than one perspective to look at.

That’s certainly the case for E10 petrol. For supporters, this greener fuel is essential in helping the UK to lower its carbon emissions. But for others, it’s an engine-destroying nightmare that doesn’t actually achieve anything. Which side has the more compelling case? In this post, we’ll look at what E10 is and some of the problems surrounding it. Then in Part Two, we’ll consider the points in its favour, and try to give our overall verdict.

So, what is E10?

In a nutshell, E10 petrol is a type of fuel which contains 10% bioethanol. Bioethanol is an alcohol produced by fermentation of several plant materials, including sugar cane, grains, and waste wood.

In the UK, our petrol has actually contained bioethanol for the last ten years. Though the labelling hasn’t made this clear, regular forecourt petrol is technically E5, indicating that it contains up to 5% of the plant-derived fuel. Diesel contains up to 7%. E10 simply has a greater proportion within the mix.

E10 is the default fuel in several countries, including France, Finland and Germany. However, until recently, it’s not been easy to get hold of in the UK. All that changed with the next stage of the government’s Renewable Transport Fuel Obligation. This requires 9.75% of all transport fuels to come from renewable sources by 2021.

To implement this, forecourts are in the process of switching to E10 as the standard. The full scale rollout began in September this year.  That doesn’t mean E5 will disappear completely, at least not immediately. It will still be available until at least 2026, when its status will be investigated.

According to Government figures, switching to E10 will reduce the UK’s transport emissions by 2%, the equivalent of removing 350,000 cars from the road. As Transport Secretary Grant Shapps put it:

…there are steps we can take to reduce emissions from the millions of vehicles already on our roads – the small switch to E10 petrol will help drivers across the country reduce the environmental impact of every journey, as we build back greener.

But as we will see, it isn’t quite that simple.

E10: The Case Against

OK, there are plenty of media outlets who, for whatever reason, automatically attack every green initiative. But even when we filter out their noise, we’re still left with some legitimate concerns about the E10 switch-over.

Let’s take these in turn:

1. E10 can damage older cars

Since 2011, all cars sold in the UK have had to be compatible with E10. Older vehicles, however, can be damaged by E10. In particular,drivers of pre-2002 vehicles are advised not to use it at all. It’s well-established that the higher ethanol content of the fuel can:

  • corrode a variety of engine parts, including “rubber parts, gaskets, seals, metals and plastics
  • cause deposits to shift within susceptible engines and fuel systems, potentially resulting in blockages.
  • result in condensation within the fuel tank if the car is unused for long periods
  • cause pre-detonation or pinking, with the associated rough running.

None of this is good news for the drivers of older and/or classic cars. They are stuck with either replacing their vehciles, upgrading the most vulnerable parts (not that this will sort out running issues), or continuing to use E5. Which leads us onto the next problem.

2. Alternatives to E10 are more expensive…

Drivers forced into using E5 petrol can anticipate paying more at the forecourt. It’s sold as ‘super unleaded’, or high octane 97-99 RON fuel. Although this offers improved fuel economy compared to E10, that’s unlikely to offset its substantially higher price. In most places, you can expect to pay between 10p and 12p more a litre for E5 petrol. For a 2009 Ford Fiesta, that’s an increase of up to £5 for a full tank. For a Ford Sierra, it’s more like £7.

3. …which hits low income drivers

The Society of Motor Manufacturers estimate that E10 is suitable for 92.2% of the petrol-engined vehicles on UK roads. That still leaves up to 600,000 vehicles that should not be using it. And on the whole, older cars tend to be owned by people on lower incomes.

Already beset by rocketing domestic energy bills, the last thing people on a low income need is a hefty increase in the costs of their petrol.

4. E10 gives lower fuel economy

At this stage, you could argue that no change benefits absolutely everyone, and that the vast majority of car owners won’t be financially impacted by the switch to E10. Except that’s not quite true either. Because regardless of your vehicle type, when you switch to E10, you’ll see a decrease in fuel economy.

This is because when ethanol is burned, it releases around a third less energy than the equivalent volume of petrol. The amount of the deficit depends on the amount of additives used in the ethanol, but the net result is fewer miles per gallon when you’re running on E10. The exact loss in fuel economy is debated, but the RAC estimates it could be around 3%.

With petrol prices continuing to rise anyway, that’s another unwelcome assault on most motorists’ bank accounts.

5. Dubious sustainability claims

All these disadvantages, of course, have to be weighed against the UK’s obligation to lower greenhouse gases (more on that in Part Two). But what if bioethanol isn’t even that sustainable?

As a strategy, growing crops to put into fuel tanks has plenty of critics, including some environmentalists. It’s been argued that it’s a terrible use of land, offering all the environmental disadvantages of monoculture — such as using huge amounts of water and decreasing biodiversity — with none of the advantages (such as growing our own food). There are even disputes about how carbon neutral bioethanol really is.

So, Pretty Damning for E10?

So far, so terrible for E10. It damages older cars, hits the less well-off particularly hard, means higher motoring costs for almost everyone and has dubious environmental credentials. Case closed? Not quite. As we said earlier, there’s two sides to every coin. We’ll see you in a couple of weeks with the flip side.

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