Approximately 36,000 Mw of new natural gas generation is scheduled to come on line in North America during March through September 2003. Of that, about 94% of the capacity is located in the US, 4% in Canada, and 2% in Mexico. These additions include a mix of combined-cycle units (79% of the total Mw) and combustion turbine units (21%).1
We assume an average efficiency of 54% and an average run-time of 21 hr/day for the combined-cycle units, and 38% and 14 hr/day, respectively, for the combustion turbine units.2 Hence, these additions alone will add 1.7 tcf/year (4.6 bcfd) to the natural gas demand in North America.
Some reliability assessment studies are careful to cover all possibilities. For example: "Government publications forecast the ready availability of adequate quantities of natural gas at market prices. ... [however]. As with electrical curtailments, the security of the gas delivery system can be maintained through the use of gas curtailments."3
Thus, with good luck—such as moderate seasonal temperatures, and favorable reservoir fills and plant availability—North America may squeak by the peaking periods for natural gas over the next few years, but only under risk of "rolling gasouts" in regions where supplies fall short. All this, while the news media focuses on wind energy, fuel cell research, and "the hydrogen economy of the future."
References
1. NERC, 2003 Summer assessment: Reliability of the bulk electricity supply in North America, May 2003, Appendix 1, www.nerc.com/
2. Kehlhofer, R.H., Warner, J., et al., Combined-cycle gas & steam turbine power plants, 2nd Edition, PennWell Publishing Co., Tulsa, 1999, 298 p.
3. NERC, Reliability assessment 2002-2011: The reliability of bulk electric systems in North America, October 2002, pp. 23-26, www.nerc.com/
Richard C. Duncan, Electrical Engineer
Seattle
Walter Youngquist, Consulting Geologist
Eugene, Oregon
