• Overview
  
  
• Overview: Conventional Oil
  
  
• Conventional Oil: A Simple Estimate
  
  
• Conventional Oil: A More Realistic Estimate
  
  
• Overview: Natural Gas
  
  
• Natural Gas: A Simple Estimate
  
  
• Overview: Coal
  
  
• Coal: A Simple Estimate
  
  

In 2001,oil provided 39% of the energy that is “consumed” [1,2] by all the people of the world. The International Energy Outlook 2004 (IEO 2004), published by the United States Department of Energy (USDoE), contains a projection that, in 2025, oil will provide 39% of the energy consumed globally. It is important to note that the authors of the IEO 2003 also project global oil consumption to increase by an average of 1.9% per year from 2001 to 2025.

There exist two significantly different estimates of the amount of conventional oil that may ultimately be extracted from the Earth. These estimates were made by the United States Geological Survey (USGS) and separately by industrial/academic experts.

The USGS estimates that there are approximately 3000 billion barrels of conventional oil (Bbo) that may ultimately be extracted.[3] Because the world has already consumed approximately 1000 Bbo, that leaves approximately 2000 Bbo as the remaining conventional oil.

The industrial/academic experts (such as Colin Campbell, Jean Laherrere, and Ken Deffeyes) estimate that approximately 2000 Bbo may ultimately be extracted.[4,5] As above, because the world has already consumed approximately 1000 Bbo, that leaves approximately 1000 Bbo as the remaining conventional oil.

It is important to keep in mind that the estimates described above concern conventional oil. We are not considering the "heavy" oil which can be extracted from Venezuela, or the oil shale of Utah in the United States. We especially note a significant change from the IEO 2002 that occurred in the IEO 2003: the reclassification by the Oil & Gas Journal [6] of heretofore non-conventional oil from the Athabasca tar sands in Alberta, Canada, as conventional oil. In short, Canada suddenly became the nation with the second highest reserves of "conventional" oil. According to the IEO 2004, the total of global proved reserves is 1,266 Bbo. This figure lies between the estimates (described above) of the USGS and the industrial/academic experts. The IEO 2004 also estimates the total of proved reserves, reserve growth, and undiscovered conventional oil to be 2935 Bbo. Note that this estimate is nearly three times greater than the estimates of experts such as Campbell and Deffeyes.

[1] Strictly speaking, energy is not “consumed”, but rather is converted into different forms. When most people speak of "consuming" energy, the process they are describing is the conversion of energy to useful work or to energy stored in the form of (new) chemical bonds. During the conversion process, a portion of the available useful energy is transformed into radiant energy (light) and thermal energy (heat).

[2] Energy Information Administration, Office of Integrated Analysis and Forecasting, International Energy Outlook 2004, rep. no. DOE/EIA-0484(2004), U.S. Department of Energy, Washington, D.C. (April 2004).

[3] United States Geological Survey World Assessment of Petroleum Resources, 2000, at http://greenwood.cr.usgs.gov/energy/WorldEnergy/DDS-60

[4] Colin J. Campbell and Jean Laherrere, "The End of Cheap Oil", Sci. Am. 278 (3), 78-83 (1998).

[5] Kenneth S. Deffeyes, Hubbert's Peak: The Impending World Oil Shortage, Princeton University Press, Princeton, New Jersey, U.S.A., 2001.

[6] "Worldwide Look at Reserves and Production," Oil & Gas Journal, 100, No. 52, 114-115 (2002). (December 23, 2002)