Petrol to Ethanol Ratio (E10) Increase

The standard 95 octane petrol grade will shortly go from E5 up to E10. E10 petrol contains up to 10% renewable ethanol, which helps to reduce carbon dioxide (Co2) emissions associated with petrol-powered vehicles and machinery and tackle climate change. Petrol in the UK currently contains up to 5% renewable ethanol, known as E5. These changes do not apply to diesel fuel.

However, some petrol-powered industrial equipment such as hand tools, small generators, water pumps etc. may not be compatible with E10 fuel. It appears that stored/unused fuel – suggested within 4 weeks – can ‘thicken’ and therefore causing potential fuel filter or carburettor jet blockages. Petrol containing ethanol absorbs water - usually through condensation - and once saturated, the ethanol and water can separate from the petrol. The result is that the water can settle in a fuel tank, carburettor or fuel injection system and cause both blockages and internal corrosion. Ethanol is a solvent and may cause corrosion of materials such as aluminium, brass, copper as well as potentially causing rapid deterioration of seals, gaskets and fuel lines.

It is further alleged that an increased ratio of ethanol may alter the air/fuel ratio, causing an engine to run leaner due to the oxygen content in ethanol. E10 fuel has been available in many European countries for quite a while so more modern equipment should not be affected by the change. However, equipment owners and suppliers are recommended to consult with the equipment manufacturer to check the compatibility of their equipment with E10 fuels. Some manufacturers are further suggesting that all fuel is emptied from the machine when not being used for a long period, whilst others recommend additives which stabilises the fuel and prevents petrol from deteriorating.

E5 fuel will still be available with 97 or above octane petrol and obtainable from petrol suppliers for the foreseeable future. Petrol fuel pumps will be clearly labelled as either 95 RON E10 or 97 (or above) RON E5.

More information can be found at https://www.gov.uk/guidance/e10-petrol-explained