Fossil Fuel Lifetimes

Natural Gas Lifetime: A Simple Estimate

Input the global remaining reserve, consumption rate, and annual percentage change.
Remaining Reserve Tcf
Consumption Rate Tcf/yr
Annual Percentage Change in Consumption %
Press the button to generate the graphs below.
Suggestions and Questions
  • The default values are from the United States Department of Energy. Press the "Graph It!" button to generate the graphs.
    With these default values, how many years from the present does it take for the remaining reserve to decrease to zero?
  • Note that it is possible to realize a negative annual percentage change through greater efficiency, conservation, or the use of other primary energy sources. Try using a modest value, such as -0.3%, and press the "Graph It!" button.
    What effect does using a negative annual percentage change have on the number of years until the remaining reserve is zero?


Graph of Remaining Reserve versus Time



Graph of Consumption Rate versus Time

After generating the graphs, place the cursor over the point where the remaining reserve achieves a value of zero. Then click the left mouse button. A rectangle should appear with two numbers; these numbers are the coordinates of the cursor. The first number is the number of years for the remaining resource to achieve a value of zero.

This page was last updated on 02 September 2003 by E.R. Behringer.