E5 is usually more expensive than E10 because it's often sold as premium fuel (like 97+ octane) with higher performance, while E10 is standard (95 octane), making it cheaper to produce and buy, despite E10's lower energy content requiring more fuel for the same distance, though this is often negligible for most drivers. E5's higher cost comes from its higher octane rating and being a better fit for older or performance cars, while E10's lower price reflects its standard, higher ethanol blend for modern vehicles.
E10 will burn slightly better than E5, cause a little less soot, will improve the longetivity of the fuel a tiny bit (as it can bind up more water before reaching a critical point) and is cheaper and better for the environment.
E10 is cheaper than E5, as E5 became premium unleaded, and E10 is the same price as standard unleaded petrol. The UK government states a 1% reduction in fuel economy using E10 vs E5, so the change to E10 for most drivers isn't very noticeable, and there should only be a big impact for drivers of older cars.
Your car is more than new enough that you'll never notice a difference. Only reason to put E5 in a car that new is if the engine is high compression and it needs the higher octane.
If you do accidentally fill up with the wrong type, don't worry too much. The Department for Transport has stated that mixing the two together won't cause issues.
Will E5 Petrol Eventually Be Phased Out? Although there is significant debate surrounding E10 vs. E5, there are no concrete plans to completely phase out E5 fuel in the UK. E5 remains available as a “super” grade option for vehicles that aren't compatible with E10.
The short answer is yes, E10 fuel does give less mpg than E5. This is due to the fact that E10 fuel contains up to 10% ethanol, which is an alcohol-based fuel source. Ethanol has a lower energy content than gasoline, resulting in decreased fuel economy. It is also cheaper, and slightly better for the environment.
Performance: Some drivers report better performance and fuel economy with E5, especially in older vehicles. Peace of mind: If you're unsure about your vehicle's compatibility, using E5 can provide peace of mind.
Octane Rating Explained (RON 95 vs RON 97/99)
Unleaded (95 RON) works perfectly for most cars designed for regular petrol. Super unleaded (97–99 RON) provides better protection in engines with higher compression ratios.
The storage life of petrol is one year when stored under shelter in a sealed container. Once a seal is broken the fuel has a storage life of six months at 20°C or three months at 30°C. The storage life of petrol in equipment fuel tanks is one month.
A combination of additives in the E5 petrol help clean the injectors and fuel lines, clearing deposits of carbon and any lacquer build up which bolsters performance.
Nowadays, a lot of vehicles are getting E10 fuel, which may not be the thing that your vehicle needs.
The big takeaway is that E5 works better with older engines, classic cars, and performance vehicles that aren't built for E10. Some drivers even find they get more miles per litre from E5, which helps offset the higher price.
While most cars are compatible with E10 fuel, some cars manufactured before 2011 may not be compatible with E10 and require you to use E5 petrol instead. If you're unsure about compatibility, you can do a quick and easy E10 compatibility check on gov.uk for free.
Yes, you can mix them. E5 and E10 petrol are fully compatible in UK cars approved for E10.
According to government estimates, E10 fuel is compatible* with almost all (95%) of the petrol-powered vehicles on the road today. This, of course, leaves 5% of vehicles unable to use the fuel, many of which are older and classic cars.
Shell V-Power features enhanced octane quality. With an octane rating of 99 RON, Shell V-Power is designed to provide more power and improved responsiveness in many modern cars.
In short, drivers of standard, well-maintained vehicles won't notice the difference between using premium fuel against standard petrol or diesel. In fact, the biggest difference between the two is the amount of cetane or octane in the fuel.
If you do insert the wrong fuel into your car, truck, or SUV it can cause incidents including shutting down your car, damaging the engine, and more internal issues with your vehicle. It is important to be mindful of what type of fuel your vehicle requires, and what type of fuel you're actually putting into your car.
Providing your vehicle is compatible with E10 petrol, there's no reason you can't mix the two grades of petrol (E5 and E10). It's perfectly safe to mix them in the same tank or fill up with E5 if E10 is not available. If you put E10 petrol in a non-compatible vehicle, simply fill up with E5 ('Super') petrol next time.
Premium fuel additives are thought to reduce friction which results in keeping the engine's components clean. This also creates a more efficient performance. Professionals say that older vehicle engines with unknown history may benefit from additional cleaning with premium fuels.
MPG, or miles per gallon, is the distance, measured in miles, that a vehicle can travel on a gallon of fuel. If you're shopping for cars in terms of fuel efficiency, this is the single most important factor. The higher a vehicle's MPG, the better its fuel economy is.
Regular petrol is generally the greener option
At the unleaded pumps you'll normally see two options: regular, or E10, and a premium option labelled E5. E10 means there is 10% ethanol in the fuel mix; E5 means 5%. If you only look at mileage per pound, the premium shouldn't have any advantage.
Symptoms of Using the Wrong Fuel
Regular fuel in Ireland is the 95-octane petrol you see everywhere.