FIGURE 4.1 Historical data on helium sales for the past 20 years as well as scenarios for future sales at various rates of growth.

Forecasting the future supply of natural resources beyond what is currently being exploited is a much more difficult task, given the difficulties of assessing both geologic and economic uncertainty. However, because helium availability is tied to natural gas production and processing, analysis of the natural gas situation may be a useful means of gauging the possibility of future helium supplies.

As of December 31, 1997, proved reserves of natural gas in the United States were estimated to be 167 trillion scf (4.6 trillion scm) (U.S. Department of Energy, 1998a). During 1997, the U.S. produced 19.9 trillion scf (550 billion scm) of gas (U.S. Department of Energy, 1998b), for a reserves/production ratio of 8.4 years. Continued supplies of natural gas are a result of the dynamic natural gas industry in the United States, which is readily replacing produced reserves through new field exploration and improved recovery technology. Were this not so, such a low reserves/production ratio would result in rapid declines in the availability of natural gas. Using the production numbers above as a baseline, the committee generated Figures 4.1 and 4.2 to estimate when the private helium industry will need to buy the government-owned helium. Because the data on helium demand are inadequate for predicting future trends in helium use, the committee considered a range of possible scenarios for growth in helium consumption.