THE SAN FRANCISCO Chronicle and the Commonwealth Club of California sponsored a "debate" over the future of the Hetch Hetchy dam Nov. 17, and the key part of the issue was almost entirely ignored.

The panel that discussed tearing down the O'Shaughnessy Dam, in Yosemite National Park – the centerpiece of the city's water system – included nobody who could address the most obvious, central argument against demolishing the dam. There was nobody to argue for public power.

Sure, Susan Leal, the general manager of the San Francisco Public Utilities Commission, brought the issue up, but the SFPUC has refused to move on public power from the beginning. The facts that were largely missing from the debate – and entirely missing from the Nov. 18 Chronicle story on it – were that Congress allowed the city to build the dam only because it was supposed to generate public power, that it remains the centerpiece of any future public power system, and that the big winner in any move to tear down the dam would be Pacific Gas and Electric Co.

It's curious that the leaders in the tear-down movement define themselves as "environmental" groups, since the actual environmental impacts of removing the dam – at least in the immediate future – are pretty grim. Replacing more than 200 megawatts of hydroelectric power in San Francisco would inevitably require more fossil-fuel generation, and that would likely mean at least one of the two pollution-billowing power plants in southeast San Francisco would stay open for many years.

Sure, removing the dam some day is a valid goal, but sadly, this city is a long way – many years – from being able to replace 200 megawatts with entirely renewable energy.

The Raker Act of 1913 allowed San Francisco to build the dam for water – as long as it was also used for public power, as the anchor of a public power system designed to compete against PG&E. That fact makes San Francisco the only city in the United States with a federal mandate for public power. And discussion about the dam's future has to start with that essential fact.

But the Chronicle and the Commonwealth Club never contacted anyone from the public power movement to be on the panel. John Diaz, the Chron's editorial page editor, told us he thought that Leal and the Modesto Irrigation district representative would cover the public power points (as if public power was just a sideshow in this grand debate).

The Chron's story made it appear as if the only issue was the cost of removal and the construction of new water facilities (the costs, of course, would be huge – and would lead to absolutely no new revenue for a cash-starved city). The real cost – the threat of damaging the future of public power, which would bring hundreds of millions a year into city coffers – wasn't even on the table.

Shame on the Chron, the Commonwealth Club, the Environmental Defense Fund, and everyone else involved in this charade. We're all for talking about restoring Hetch Hetchy Valley – once the city has an established public power system and the ability to replace the power generation with municipally owned renewable energy.

Until then, this sort of "debate" helps nobody but PG&E.