Used cooking oil as an alternative energy source

...small plants in Britain...are processing, and often selling to private motorists, used cooking oil, which can be poured directly into unmodified diesel cars, from Fords to Mercedes.

Last year, when the price of crude oil topped $147 a barrel, a number of large companies in Europe and the United States were spurred to set up plants to collect and refine used cooking oil into biodiesel.

The global recession and the steep drop in oil prices have now killed many of those large refining ventures. But smaller, simpler ones like Mr. Friedlos’s are moving in to fill the void with their direct-to-tank product, having been deluged by offers of free oil from restaurants.

Used cooking oil has attracted growing attention in recent years as a cleaner, less expensive alternative to fossil fuels for vehicles. In many countries, including the United States, the oil is collected by companies and refined into a form of diesel. Some cities use it in specially modified municipal buses or vans. And the occasional environmentalist has experimented with individually filtering the oil and using it as fuel.

Vegetable oil is cleaner than either gas or diesel, producing virtually no carbon dioxide, the main greenhouse gas linked to climate change, and far fewer of the tiny airborne particles in pollution that are harmful to human health. But if the cooking oil is not adequately filtered or prepared for use in cars, studies show, it can also produce high levels of another chemical, NOx, the main component of smog.