The capital has the highest concentration of food businesses in the country, which together produce between 32 and 44 million tonnes of used cooking oil (UCO).

If this could be processed into biodiesel, it could save 50,000 tonnes of carbon dioxide. It would also reduce the reliance on food crops for biofuels and create new jobs, said researchers.

The vast majority of UK biodiesel is currently being processed in the north of England and Scotland. However, the Greater London Authority is hoping provide a catalyst for a closed loop market for UCO and biodiesel in the capital. It therefore commissioned LRS Consultancy to carry out a study to determine whether a biofuel refinery in the city is feasible and what some of the challenges might be.

Speaking to today, Hugh Smith, principal consultant at LRS, said the quantity of UCO wasn’t in doubt, but there remains a “divergence of opinion” over whether the creation of such a plant is economically viable.

In its favour is the well-established market for UCO, and while the margins for production of biodiesel are “fairly thin”, there are incentives in place, such as double Renewable Transport Fuel Certificates, which the general appeal of the process “undeniable”.

Data from the Department for Transport for 2011 also shows that 89% of UK biodiesel feedstock for transportation is produced from UCO, a proportion that has risen rapidly over the last five years and was just 50% in 2010-2011.

Many London boroughs run part, or all, of their vehicle fleets on biodiesel. Some of these fleets run on UCO. The Mayor of London’s Transport Strategy seeks to increase the use of biodiesels among the city’s boroughs.

Another incentive is the move to limit the amount of food crops used to produce biofuels. Following concerns over the displacement of food crops for biofuel crops, the European Parliament last month backed plans to cap the use of food crops at 6% (rather than 10%).

LRS also looked at the potential to use fats, oils and greases (FOG’s) to create biodiesel. According to Thames Water, half of the 56,104 drain and sewer blockages each year are caused by these substances.

It is illegal for FOG’s to be poured down the drain, either at commercial or domestic properties, but policing the latter stream is impossible.

Of the four main suppliers of biodiesel interviewed by LRS, one company felt that a 30-50,000 tonnes per annum facility producing biodiesel from FOG’s would be “viable” and that they were interested in taking this forward.

In August, Thames Water removed the biggest ever blockage of FOG – also known as a ‘fatberg’ – from a London sewer. It was the size of a London bus.

Vehicles running on biodiesel produce around 25% less carbon emissions than those running on traditional fuel.

David Burrows

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