E10 fuel

The government has announced it is to press ahead with the introduction of E10 fuel as the standard fuel. At the moment when you pull up to the pump and go for the standard petrol, you will see E5 on the pump

 This means the fuel contains 5% ethanol. Ethanol is a bio-fuel produced from plants, in the main sugar cane and grain, in short – alcohol.

Those of you with illegal stills will know exactly what I mean. The ethanol was added to reduce the carbon emissions caused by burning the fossil fuels.

What will it mean to you? As shown above the government states it will help reduce the carbon footprint, but by how much? Adding ethanol will reduce fuel economy. Research has shown by going from 5% to 10% ethanol, fuel efficiency is reduced between 3%-10% so more fuel used and more cost for the same journey than by using E5.

E10 is very common on the continent (10% ethanol) and has been for many years. The government now intend to roll it out as the standard in the UK to help meet their carbon emission targets. Why only now? Why not sooner?

Ethanol might mix with petrol and burn, but there is no guarantee that every bike will be able to use an E10 mix. The current E5 standard was adopted because it was considered that a 5% ethanol ratio was the maximum that engines and fuel systems designed for conventional petrol could safely deal with. Rising above that figure brings risks, particularly to older vehicles.

The government’s own consultation document says “…vehicle compatibility has been the main barrier to the introduction of E10 so far. Not all vehicles have been approved by their manufacturers for fuel with more than 5% ethanol.

Among the problems with ethanol is that it prefers to burn at a different air/fuel ratio than petrol. On a bike with fuel injection, a three-way catalytic converter and a lambda sensor then there is not necessarily a problem as the exhaust sensor can tell the fuel injection to compensate. Unfortunately motorcycle manufacturers only adopted the technology around 2010, this could be problematic as the average age of a bike in the UK is 14.7 years old. Also it is estimated to date that 700,000 vehicles in the UK are non-compliant to E10. To that end E5 will still be available although at a higher cost.

Other problems are that ethanol is hygroscopic, which means it absorbs and mixes with water, even drawing it from the air around. This can cause corrosion and expose parts of the fuel system never designed to be in contact with water become contaminated. Ethanol is also a solvent which means rubber, plastic, and fibreglass parts that were designed to be in contact with pure petrol can melt when exposed to E10.

Although the water attracting properties of E10 aren’t necessarily a massive problem if you are constantly using a bike and running through tanks of fuel, they can be amplified when the bike is left unused with petrol in the tank.

This is a big issue for bikes, since many are laid up or little used over winter. During that time E10 has a reputation for going stale and undergoing ‘phase separation’ when the bike isn’t used. That means the ethanol falls out of solution with the petrol as it absorbs more water. The result could be the engine failing to start, requiring the fuel in the tank to be changed. This process can take place in as little as 3 months. So be alert to the introduction of this fuel and if you ride an older bike check whether it will be compatible.

A list – not exhaustive – of compliant models has been posted on the LAM Forum.

Steve Pratt, National Observer