To B30 or not to B30

Car makers have raised concerns with a supermarket over the sale of a high blend biodiesel called B30. Many are worried that sensitive engine components like fuel injectors could be damaged by the fuel which is currently sold through 113 Morrisons sites across the UK.

Filling up with B30 threatens owners' warranties and trade body the Society of Motor Manufacturers and Traders (SMMT) has urged the supermarket to display clearer and more prominent warnings for its customers.

B30 is 30% biomass, a much higher blend of FAME (Fatty Acid Methyl Ester) than regular diesel which can include up to 5% natural matter. Warnings on Morrisons' nozzle clips advise customers to check with the manufacturer before use, a statement repeated in a two-inch high sticker on the pump itself. But manufacturers say these signs are too small.

The SMMT has confirmed that manufacturers are undertaking tests on the fuel. But Morrisons' website already claims B30 is compatible with most diesel engines. A minority of car makers share their confidence, but the vast majority recommend against its use.

What do the car makers say?

We followed advice and called 17 customer relation departments to check the position, claiming to be in the market for a new diesel car. Ford, Mercedes and Toyota referred us to the local dealer for technical advice.

Fifteen - Audi, BMW, Fiat, Ford, Honda, Hyundai, Jaguar, Kia, Mercedes, Nissan, Renault, Toyota, Vauxhall, Volvo and VW - told us that B30 was not recommended for use with their diesel engines. Peugeot and Citroen were the exceptions.

BMW qualified their position saying the fuel was not currently recommended, but confirmed it was undergoing tests, so their position could reviewed in the future. The local Mercedes dealer was most direct; "we've had an email about this; you must, must not use the fuel."

Consumer confidence

Biofuel has had a rocky ride since it was first posited as an environmentally-friendly replacement for fossil fuels. Politicians climbed on board, then promptly jumped ship amid criticism that crops grown for fuel were contributing to global food shortages and price hikes for the world's poorest.

In February 2007, a series of breakdowns in the UK were traced to a suspect batch of fuel, supplied by Harvest Energy, the company now supplying B30 to Morrisons. Unusually high levels of silicon were detected, causing the failure of hundreds of cars' oxygen sensors and prompting Tescos to take out full page apologies in the press with a promise to pay for repairs.

While failures on that occasion were caused by contamination in petrol, questions about the suitability of higher blend biodiesel could further rock confidence in blended fuel. The industry fears problems with B30 may only arise after time or if service schedules are not rigorously maintained.

The suppliers' position

Morrisons has pioneered the supply of higher-blend biofuels and was the first fuel retailer to sell E85, a high-blend bioethanol fuel, widely used in Sweden, and suitable for some Saab and Ford models on sale in the UK. Twenty one sites across the UK sell the fuel.

However, they were less keen to talk to us about concerns raised by the industry over the use of B30 and the issue of labelling. "Our fuel people are very busy," was all a flustered spokesman would say.

Harvest Energy were more open. They told us cars and vans had been running on the fuel for the last two years with no operational issues. They also claim industry concerns like separation in storage and cold weather problems have been eliminated from their B30 feedstock blends.

The legal position

The fact is Morrisons are selling an entirely legal fuel. Harvest Energy produces it to EN590 fuel specifications (other than its high FAME content) and Europe's biofuel standard EN14214.

The European Commission also appears to have given the green light to higher blend biofuels in its new Fuel Quality Directive. To the chagrin of car makers it has allowed the use of metallic additives, and in a contradiction worthy of the best of European lawmaking, mandates a maximum FAME content of 7%, while allowing member states to market fuel with a higher content.

What does it mean for customers?

Confusion and contradiction, even at the European level, demonstrates the problem for motorists. Harvest says B30 delivers greenhouse gas savings of around 15% from well to wheel, a figure independently verified by the Renewable Fuels Agency, which audits the government's Renewable Transport Fuel Obligation. The fuel is also audited on a range of other sustainbility criteria.

But, the response to our calls reveals very different views on its suitability for modern diesel engines. Perhaps there is a degree of over-caution pending further tests of B30, but questions remain over its compatibility with sophisticated components in diesel engines that run to ever-tighter tolerances.

One thing is clear: ignoring manufacturer advice - or missing the small warning notices posted on B30 pumps - risks invalidating warranties. That could mean expensive repair bills further down the line.