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Top 8 Synthetic Fuels

        Auto | Biofuels

Oil Sands
Aerial views of the Syncrude Canada Ltd. and Suncor Energy Inc. tar sands in Canada.
Aerial views of the Syncrude Canada Ltd. and Suncor Energy Inc. tar sands in Canada.
Veronique de Viguerie/Getty Images

Oil sands, or tar sands, are the third source of synthetic fuels that are classified as syncrude. A mix of water, clay, sand and a substance called bitumen, oil sands occur naturally. Bitumen is a very thick oil-like substance that is the consistency of very sticky Jell-O at room temperature. It contains many more impurities than conventional crude oil, including sulfur, nitrogen and heavy metals that must be removed before the bitumen can be used for fuel [source: U.S. Energy Information Administration]. The sands are usually gathered through open pit mining. In situ recovery is also possible through injecting steam or chemicals to break up the sands. But in situ collection consumes huge quantities of water and power and is also less cost-effective.

To process oil sands to a state they can be sold as syncrude, they're washed with hot water to separate the bitumen from the clay and sand. The bitumen is then subjected to huge amounts of heat and pressure, and natural gas is introduced. This converts the hydrocarbons in the material into a form that is more easily burned as fuel [source: U.S. Department of the Interior]. The massive amounts of water and power needed to transform oil sands from deep underground deposits to usable fuels make it a controversial fuel because of its environmental impact. The toll on the environment, from strip mining and the disposal of waste water, has led to much controversy in Canada, where most of the world's oil sands are currently mined [source: Kunzig].