Non-conventional oil is oil extracted using techniques other than the traditional oil well method. Currently, non-conventional oil production is less efficient and some types have a larger environmental impact relative to conventional oil production. Non-conventional types of production include: tar sands, oil shale, bitumen, biofuels, thermal depolymerization (TDP) of organic matter, and the conversion of coal or natural gas to liquid hydrocarbons through the Fischer-Tropsch process. These non-conventional sources of oil may be increasingly relied upon for transportation fuel should conventional oil experience depletion. Conventional sources of oil are currently preferred because they provide a much higher ratio of extracted energy over energy used in extraction and refining processes. Technology, such as using steam injection in tar sands deposits, is being developed to increase the efficiency of non-conventional oil production.

Tar sands

A potentially significant deposit of non-conventional oil is the Athabasca Tar Sands site in north-western Canada as well as the Venezuelan Orinoco deposit. It is estimated by oil companies that the Athabasca and Orinoco sites (both of similar size) have as much as two-thirds of total global oil deposits but they are not yet considered proven reserves of oil. Extracting a significant percentage of world oil production from tar sands may not be feasible. The extraction process takes a great deal of energy for heat and electrical power, presently coming from natural gas, itself in short supply. There are proposals to build a series of nuclear reactors to supply this energy.

Oil shale

Main article: oil shale

Bitumen

Main article: bitumen

Biofuels

Biofuels such as biodiesel and ethanol are also hydrocarbon fuels.

Thermal depolymerization

Thermal depolymerization (TDP) has the potential to recover a lot of energy from existing sources of waste as well as pre-existing waste deposits. Because energy output varies greatly based on feedstock, it is difficult to estimate potential energy production.

Coal and gas conversion

The conversion of coal and natural gas has the potential to yield great quantities of non-conventional oil albeit at much lower net energy output. Because of the high cost of transporting natural gas, many known but remote fields are not being developed. Conversion can make this energy available even under present market conditions.

See also

• Renewable energy
• Future energy development
• Hubbert peak
• Energy development