An American energy company with biodiesel and ethanol operations will be buyng some of its green fuel from down under.

The New York Times reports that Valero Energy has signed a five-year deal with Australian biofuel refiner Mission NewEnergy to obtain biodiesel made from jatropha. Valero will also be able to buy a 25 percent stake in Mission:

Mission will supply Valero with up to 60 million gallons of biodiesel per year, starting next year. Under the terms of the agreement, Valero can double that amount and extend the contract by an additional five years. The value of the contract could be as high as $3.5 billion, Mission said in a statement.

Jatropha is a family of oil seed plants that can grow on marginal soil without displacing land used for food supply.

Already the nation’s biggest petroleum refiner, Valero has been steadily increasing its presence in the biofuels market. Earlier this year, Valero obtained seven ethanol refineries from financially strapped VeraSun, and Valero got into the biodiesel business this fall when it started a venture in Louisiana with Darling International Inc. to develop an animal fat biodiesel plant.