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

During 2001, coal provided 24% of the energy that is “consumed” [1,2] by all the people of the world. The International Energy Outlook 2003 (IEO 2004), published by the United States Department of Energy (USDoE), contains a projection that, in 2025, coal will provide 23% of the energy consumed globally. It is important to note that the authors of the IEO 2004 also project global coal consumption to increase by an average of 1.5% per year from 2001 to 2025.

The global reserves of coal total 1083 billion short tons (Bst).[2] The United States contributes 271 Bst to this total.[2] Because of the relative abundance of coal in the United States, it has sometimes been touted as our final energy source, and in fact many electrical generating plants burn coal. However, burning coal is less friendly to the environment than burning natural gas.

Please note that the reserves quoted immediately above have not changed from those quoted in the IEO 2003, despite a year of consumption and (presumably) exploration.

The calculations that you can perform by using the web pages linked to this page (see the menu at the left) are meant to help you gain a feel for the "lifetimes" of the fossil fuels. At present, there is one method available on these web pages to estimate the "lifetime" of coal. It is a simple method, in which the annual percentage change in consumption is assumed to be constant for all time. This method is implemented on the page listed on the menu on the left. This page enables you to change various inputs, such as the amount of remaining coal reserves, the rate of consumption, and the annual percentage change of the consumption rate.

NOTE: To use this page, you must be using a browser that enables Java to JavaScript communication. PC users using Internet Explorer or Netscape Navigator 7.0 will probably experience no problem. Mac users: OS 9.1 and Netscape 7.0 works. Also, OS X with any latest-edition browser will probably work. The author has not tested these pages on all different platform/browser combinations.

Because world events can significantly alter the rate of consumption, no claim is made about the accuracy of the predicted "lifetimes". Please keep in mind that it is most useful to simply allow the numbers to vary and see how the "lifetime" of the fossil fuel changes.

[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, some 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).