However, over the next 100 years, diesel fuel was made largely from petroleum (石油). Interest was renewed in biodiesel in the mid-1970s when the energy shortage occurred, and gas prices surged upward throughout the United States. In spite of these conditions, commercial production did not take place until much later. In 1999, The National Biodiesel Board reported that 500,000 gallons per day were produced. In 2000, production increased to 6.7 million gallons per day.

　　With the continual rising costs of petroleum products in the new century, major corporations and the United States government have looked to new markets. Farmers are encouraged to grow soybeans in their fields, as the demand for soybean fuel increases. They can now get several gallons of fuel per acre of soybean.

　　Biodiesel is created by removing a thick liquid called glycerin from soybean oil. It is registered with the US Environmental Protection Agency as a pure fuel, which is known as B100, or as a fuel additive, which is called B20, a mixture of 20 percent soy and 80 percent petroleum-based diesel.

　　There are many benefits of soybean fuel.

　　Studies have shown that biodiesel from vegetable oil reduces petroleum consumption when used in place of petroleum diesel.

　　In addition, the use of biodiesel reduces CO2 in the earth’s atmosphere. This is due to the fact that growing soybeans consumes nearly four times as much CO2 as the amount of CO2 produced from biodiesel waste gases.

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