This oil blend, called soybean heating oil, can be used in conventional furnaces without altering existing equipment, said Harry Gibson, professor of agricultural and biological engineering and one of the developers of the process. Two Indiana homeowners started using soybean heating oil in their furnaces last winter, he said.

Soybean heating oil originated as a winning entry submitted by a team of Purdue undergraduates in the 2001 New Uses For Soybeans Student Contest and was further developed by Gibson and colleagues. The Purdue researchers have recently partnered with the Indiana Soybean Board to market this technology.

According to the U.S. Department of Energy, 8.1 million homes in the United States used fuel oil for heating in 2001, the last year for which figures are available. Of those homes, 6.3 million were located in the Northeast, with the majority of the remaining homes in the Midwest.

Replacing just 20 percent of the fuel oil used in 2001 with soybean oil could have potentially saved 1.3 billion gallons of fuel oil, Gibson said.

Adoption of soybean oil as an additive to petroleum-derived heating oil, which currently dominates the home heating oil market, presents strategic, economic and environmental benefits, Gibson said.

"Soybean oil is a renewable, domestic resource," he said. Gibson also said the use of soybeans as an additive in heating oil would be a boon to farmers, likely increasing the demand for their crops.

The addition of domestically produced soybean oil to fuel oil also may help buffer some petroleum price fluctuations, Gibson said.

"This effect could be especially helpful during the winter months when demand for heating oil is usually high," he said.

Unlike standard fuel oil, soybean oil contains no sulfur, and blending soybean oil into standard heating oil decreases sulfur emissions, said Bernie Tao, professor of agricultural and biological engineering.

"The decreased sulfur emission we see with soybean heating oil is a major environmental benefit," he said.

Still another benefit of soybean heating oil is that it's surprisingly easy to produce.

"Soybean oil comes straight out of the bean," Tao said. "Producing the heating oil blend is a very straightforward process. We were surprised to find that nobody else is making this."

Once the oil is removed from the bean, it goes through a process called degumming, which makes the oil more stable by removing certain compounds. Simply mixing degummed soybean oil with conventional fuel oil makes soybean heating oil, Tao said.

Soybean oil is comparably priced to standard fuel oil, said Nick Vanlaningham, a graduate student in agricultural and biological engineering who helped develop the soybean oil blend.

Over the last four heating seasons, the price of heating oil has ranged from $1 to $1.86 per gallon; over the same time period, the price of soybean oil has ranged from 93 cents to $1.72 per gallon, he said.

While it is possible to burn 100 percent soybean oil, pure soybean oil would not run efficiently in today's furnaces, Vanlaningham said.

"One of our goals is to make a product that runs well with the equipment people already have in their homes," he said. "Homeowners would need to change much of the equipment in their furnaces in order for a 100 percent soybean oil to run well, but a 20 percent blend will run with the equipment they already have." To run a 20 percent blend, homeowners would need to have a technician adjust the furnace's settings as part of a yearly service, Vanlaningham said. Furnace manufacturers recommend homeowners have their furnaces inspected and adjusted annually, so incorporating the adjustments for soybean heating oil could become part of the standard inspection, he said.

A 20 percent blend is about 2 percent to 3 percent lower in heat content per unit volume than pure fuel oil, but that difference could be balanced by the price stability of soybean oil relative to standard fuel oil, Gibson said.

Despite the advantages soybean heating oil offers, a significant obstacle to its widespread adoption remains.

"The infrastructure for mixing soybean heating oil is not in place yet," Tao said. "But it could be easily put in place. The manufacturers of conventional fuel oil could mix soybean oil in at their facilities, or fuel oil distributors could mix it in on-site."

The researchers remain optimistic that soybean heating oil has the potential to become an important fuel.

"The price of standard fuel oil will continue to rise because it comes from a non-renewable resource that will eventually run out," Tao said. "We need to switch to using renewable sources of energy like biofuels, and soybean heating oil is a good place to start."

The Indiana Soybean Board and the USDA Initiative for Future Agriculture and Food Systems funded this research. FFF/Insta-Pro of Des Moines, Iowa, supplied the soybean oil used in the studies, and Thermo Pride of North Judson, Ind., donated a new research furnace and other equipment to support the program.

Individuals interested in commercial applications of soybean heating oil should contact Michael Bryja of the Indiana Soybean Board at (800) 735-0195.