The amount of alcohol seized by Swedish customs officials has increased in recent years, in part because of greater Internet commerce.
Confiscated beverages are separated from their containers, blended with water, and taken by tanker to a plant run by the company Swedish Biogas in Linköping, 120 miles (200 kilometers) south of Stockholm.
(See a map of the country.)
There, the seized alcohol—along with other fuel sources, such as animal remains from slaughterhouses and human waste—is heated and put into anaerobic digesters. The organic materials are broken down, producing the biogas.
Almost 250 million cubic feet (7 million cubic meters) of clean-burning biogas is produced a year.
In Linköaping, a city of 140,000, biogas makes up 5 to 6 percent of transportation fuel use, and all of its public buses run on the alternative fuel.
For every liter of gasoline that is burned, 2.5 kilograms of carbon dioxide is produced, said Carl Lillehöök, managing director of Swedish Biogas.
"By replacing 5 million liters (1.3 million gallons) of gasoline with 5 million cubic meters (176 million cubic feet) of biogas, we can save 12,000 metric tons of carbon dioxide in Linköaping alone," he said.
Biofuel emissions are minimal, Lillehöök added: "If you put your finger on the inside of the tail pipe of a biofuel car, [it doesn't] get dirty."
In the process of making biofuels, the company also produces environmentally friendly fertilizers that are sold to farmers.
"From an environmental standpoint, this is a win-win business," Lillehöök said.
The company also operates the world's first biogas train, which has been running for the past year-and-a-half along the southeast coast of Sweden.
While biogas is cheaper to produce than gasoline, the challenge is distributing the fuel, Lillehöök said.
(See related: "Biofuels Could Do More Harm Than Good, UN Report Warns" [May 9, 2007].)
Sweden has close to a hundred biofuel filling stations, but few natural gas pipelines through which biogas can be transported. Instead, the gas must be compressed into bottles and shipped by truck to filling stations, significantly raising costs.
However, biofuel is still more affordable than gasoline, because it is not subjected to the same taxation.
Drivers save about 40 U.S. cents per mile when using biofuel compared to gasoline, according to Mattias Goldman of Gröana Bilister the Swedish Association of Green Motorists.
Drivers of "green" cars also don't have to pay road tolls in Stockholm, and they park for for free in many of Sweden's larger cities.
About 40,000—or one percent—of Sweden's four million cars run on alternative fuels.
Last month, Sweden launched a new green car bonus program, which rewards the owner of a new eco-friendly car with 10,000 Swedish krona (1,400 U.S. dollars) in cash from the government.
Free Email News Updates
Sign up for our Inside National Geographic newsletter. Every two weeks we'll send you our top stories and pictures (see sample).
SOURCES AND RELATED WEB SITES