How to transform garbage into greener fuels

For centuries, people have burned waste to create energy, sending carbon billowing into the atmosphere. Transforming garbage into clean fuel, however, was an alchemy confined to fiction, like the movie “Back to the Future.” Now, a handful of companies want to turn household trash into low-emissions fuels for planes, trains and trucks.
The newer, cleaner process, known as waste gasification or pyrolysis, involves cutting and drying non-recyclable trash from homes and offices, such as packaging and bottles, before blasting it with 4,000-degree-Fahrenheit steam and oxygen to break it down into hydrogen and carbon monoxide. The solids left behind are sold as road materials, and the gases produced can then be synthesized—using processes developed a hundred years ago—and refined into greener fuels, including biofuels and emissions-free hydrogen.
Sierra Energy, originally set up to provide low-carbon locomotive fuel for its parent company, Sierra Railroad Corp., has a prototype of a trash refinery in Monterey County, Calif. Canada’s Omni Conversion Technologies says it is on the verge of commercializing its waste gasifiers. In the U.K., the sustainable-fuel startup Velocys and aviation giant International Airlines Group SA aim to create Europe’s first garbage-to-jet-fuel plant and have received funding from Royal Dutch Shell PLC, while the European oil giant Repsol SA is also investing in the technology in the Spanish city of Bilbao.
“When you throw garbage into a hole in the ground, what happens is you get an enormous amount of methane coming out,” says Mike Hart, chief executive of Sierra Energy. Methane comprises 20% of global greenhouse-gas emissions and is 25 times more potent than carbon dioxide in trapping the earth’s heat, the Environmental Protection Agency says.