In late May, Rix Petroleum, a U.K. fuel distributor, launched GoGreen, a biofuels card program aimed to "green" commercial vehicle fleets.

The new program is similar to the country's plan to supply green electricity to environmentally conscious consumers. Although renewable energy isn't guaranteed to course through the wiring of a customer's home, those who purchase green power know that for every unit of electricity they consume, an equal amount of renewable electricity will be generated. Likewise, for commercial fleets that use GoGreen fuel cards to purchase conventional diesel, an equal volume of a 5 percent biodiesel blend will be purchased and added to the system by the participating fuel station operator. "It's a displaced benefit," said Rory Clarke, director of Rix Petroleum. "It's obviously not going directly into your vehicles, but the more people that embrace it, the more (Rix trademarked) BioBlend5 that goes into the system."

A network of about 1,300 filling stations across mainland Britain can be accessed with the fuel card. Rix records the purchases on each card, raises invoices for each fleet's total fuel consumption and facilitates the delivery of biodiesel to participating stations.

Since the card can only be used to purchase fuel, a record of the fuel economy of a vehicle-when, where and how often a truck, van or car has filled up-can be generated. "It's a good fuel management tool for a company," Clarke said. In addition, Rix sends out a certificate every three months to each fleet showing the amount of carbon saved with the card. Clarke estimates that for a fleet of about five to 10 trucks that use about 5,000 gallons of diesel each week, the fuel card will reduce annual carbon emissions by 2.25 to 2.5 tons. "We're making it practical for any business anywhere in the country to get access to biofuels," he said.