THE DEMAND for biodiesel is expected to grow rapidly in the next decade. Projections are that, by 2030, biodiesel will have replaced 20% of the market currently held by regular diesel. Although 85% of U.S.-produced biodiesel now comes from soybean oil, the remaining 15% is produced from some less-typical feedstock, including recycled cooking oil, animal tallow, canola and cottonseed oil.

But don't expect innovation to stop there. Researchers are working on other, predictable sources, such as oil crops canola and mustard, as well as some unusual sources.

Mustard

More than just a condiment, this low-input oil crop also shows promise for fuel production, says a University of Idaho researcher. Working with the industrial version of this seed crop, plant breeder Jack Brown is developing varieties that have as much as 40% oil content and are 90% monosaturated, making the oil simpler to process.

Chicken fat

The fat from chicken carcasses may provide a low-cost, energy-rich source of biofuel feedstock. University of Arkansas engineers obtain the scrap fat from Tyson Foods plants in the state to test different fat-to-oil conversion methods. They say the economics of the refining process are still being determined, but there is no shortage of cheap base fat.

Algae

Not all algae are just green slimy masses. Some, according to a University of New Hampshire physicist, are high-oil versions (well over 50% oil) that could be grown for biodiesel production. Michael Briggs says the rapid growth of algae, along with the relatively simple production requirements, could make it an ideal crop for warm, arid locations. His estimate is that 7.5 billion gallons of biodiesel could be produced from 500,000 acres.