Daniel Yergin's column, "It's Not the End of the Oil Age" [op-ed, July 31], referred to a report on a field-by-field study of oil production capacity. This differs from a discussion of reserves, the amount of oil in the ground. If we are significantly increasing production and therefore the supply of oil in the next several years without finding significant reserves of oil, we will be depleting the existing supply more rapidly.

If this leads to a glut on the world market and lowers prices, we will be using up valuable oil while failing to give the market the proper signals to allow us to foster conservation and develop more efficient technology and alternatives to oil.

Additionally, many of the nonconventional sources of oil that Mr. Yergin touted -- Canadian oil sands, ultra-deep-water development and natural gas liquids -- are not consistent with the affordable oil prices that are implied by the headline and the first four paragraphs.

Mr. Yergin may be right that this is the fifth time that we have been "running out of oil," but in the past 30 or 40 years, we have looked more carefully than ever before with increasingly sophisticated technology around the globe, with less and less to show for it. Had we aggressively pursued the development of solar and wind energy and conservation in the 1980s and '90s, we would be in better shape today, but apparently nobody had enough incentive to do so.

Thinking that we have "the breathing space" to address the investment and technology development required to fuel a growing world economy has not led the government or the private sector to address the energy issue in any significant or rational way. The recent energy bill doesn't even address raising automobile efficiency standards. Putting a few hybrid cars on the market will barely put a dent in the problem.

Real alternatives are decades away, and that may be cutting it a little too close for comfort.

JIM HEALD

Alexandria