The parking lot on the Avenue of the Americas in Chelsea seemed to Consolidated Edison to be the perfect spot for an electrical substation. After all, the company owned the land, and the site was in the heart of a place that desperately needed more electricity because in the last decade it had been flooded with apartment buildings and art galleries.

So, Con Edison executives said they expected little opposition to their plan for a nine-story substation, at a price of $70 million, at the corner of the Avenue of the Americas and 24th Street. The local community board even supported it as long as Con Ed met certain conditions.

But it turned out not to be that easy. The plan for the substation faced every kind of opposition from residents imaginable, from ''not in my backyard'' objections to complaints based on assumed health risks, safety concerns and the impact on property values. Ultimately, the city agency that regulates land use rejected the plan.

''It has left us really concerned about power,'' said Ed Kirkland, a long-time resident who lives a few blocks from the proposed site and is chairman of the Community Board 4 committee that reviewed the plan.

Officials from Con Ed and from the New York Independent System Operator, which runs the power grid, say they believe that at least three large plants and nearly half a dozen substations will have to be built in New York City in the next few years to keep pace with demand.

Yet energy and land use experts say it is becoming harder to find places to put power stations. And with a hot summer as a reminder of just how close trouble could be, these power officials say that their inability to build could mean more difficulties down the road.

''It was a huge blow to the reliability of the network,'' said John H. Banks, Con Ed's vice president for government affairs and its chief lobbyist. ''Chelsea is going to have a real problem.''

Across the city, almost a dozen plans exist for power plants or substations, which are used to convert electricity to voltages low enough to be transmitted to homes and businesses.

In Chelsea, the need for a new substation is particularly acute. Since the city decided to rezone the neighborhood for residential, retail and office space in 1996, demand for electricity has grown 8 percent each year, compared with about 2 percent for the rest of the city. Con Ed officials say that it is the fastest growing neighborhood when it comes to power use, and the most vulnerable to power failures.

So two years ago, Con Ed proposed building a new substation on the Chelsea lot, which it had purchased three decades earlier for that purpose. Officials at the utility said the substation could be running by 2004 on the site, which is now home to the Chelsea Flea Market on weekends.

But almost immediately, local residents -- many lured into the neighborhood during the rezoning -- formed a group, the Chelsea Alliance, to oppose the project. By the beginning of 2001, they had some powerful allies, including Councilwoman Christine Quinn, State Senator Thomas K. Duane, Assemblyman Richard N. Gottfried and the Gay Men's Health Crisis, which has a clinic for AIDS and HIV patients on West 24th Street.

The coalition opposed the project for a variety of reasons: neighborhood aesthetics, the impact on apartment values, and traffic and security concerns. The group also raised questions about environmental safety and the loss of the flea market.

Sylvia Lachter, the president of the alliance, said it would create a ''dead block'' where the city had encouraged residents to move when the neighborhood was depressed. The surrounding blocks are now filled with coffee shops, galleries and health food stores, and a hotel sits across the avenue.

Con Ed officials told residents that the substation would be safe, and went to community meetings with architectural drawings showing how the substation would mimic the facades of nearby buildings.

The alliance proposed instead that the substation be built at a site Con Ed owns at 28th Street at the West Side Highway. But Con Ed said that from an engineering perspective, that site was too far from the center of the neighborhood -- making it harder to get power to customers reliably, and that it was already being used as a maintenance yard.

But before Community Board 4 made its recommendation, politicians rejected such arguments.

Ms. Quinn said her opposition was based on the fact that ''you had one side of the government rezoning this area and telling people to come live here, buy expensive co-ops and make this a residential neighborhood,'' she said. ''Then, you have Con Ed going to another piece of the government and saying this neighborhood has grown, so let's put in something antiresidential.''

Con Ed officials say that the Giuliani administration supported the plan, but that a few weeks after Michael R. Bloomberg took office as mayor, the chairwoman of the City Planning Commission, Amanda Burden, told them the 24th Street substation was a nonstarter. In June, the city's Board of Standards and Appeals, which regulates land use, rejected the plan by a vote of 4 to 0.

In an interview, Daniel L. Doctoroff, the deputy mayor for economic development, said that the Bloomberg administration, which had helped Con Ed in its efforts to quickly build a new substation to serve parts of Lower Manhattan after the World Trade Center attack, did not take a position on the 24th Street plan.

But Mr. Doctoroff did say that given the potential for a power crisis within the next five years, officials had to come up with ways to build power stations in rapidly growing areas, and he predicted that local residents would not always be happy with the outcome.

''We certainly have a preference for siting these projects in communities that want them or do not object to them,'' Mr. Doctoroff said. ''But at the end of the day, we have an obligation to make sure the city has the energy that it needs.''

Con Edison is now negotiating with several building owners on 30th Street, between the Avenue of the Americas and Fifth Avenue, to purchase land for a substation to serve Chelsea. Con Ed has not said what its plans are for the 24th Street site.

Mr. Banks, the Con Ed vice president, estimates that such a land acquisition would add $30 million to its cost, adding that ''these types of political considerations'' are ''ultimately why Con Ed has some of the highest rates in the country.''

''You can see how hard it is going to be to build several 1,000-megawatt power plants in the city when we can't even get this, just a substation,'' he added.

In the meantime, Con Ed has placed -- and will continue to add more until at least 2005 -- several gas-fired mini-generators in Chelsea. But the generators have also angered neighborhood residents, who say they spout black smoke and are too loud.

''We would kill them if the lights went out, so I can't begrudge them the generators,'' said Mr. Kirkland, of Community Board 4.

He said that in the long term, Con Ed, power generators and neighborhoods need to learn how to work better together. ''If we are going to have electrical power, this stuff has to go somewhere, '' he said.

But such cooperation does not appear to be materializing. The Midtown Civic Association has already decided to oppose construction of a substation on 30th Street.

Published: 08 - 26 - 2002 , Late Edition - Final , Section B , Column 1 , Page 3