By the time New York Regional Interconnect died a surprising death at a state hearing last year, the proposed 190-mile power line through upstate New York had engendered a long list of opponents.

Among the transmission line's critics at the end were environmental groups, state and local officials at all levels and even power companies like Con Edison that would have been served by the transmission line. Left without a clear path to a profit, the line's developers withdrew their plans after a three-year, multimillion-dollar fight.

The move was a victory for civic and environmental groups who argued that the project would destroy views, denude thousands of acres of woodlands, physically divide communities and potentially endanger the public health. A year and a half later, though, questions remain: Are New York City's power demands as great—and the state's energy infrastructure as ill-equipped to meet those needs—as power line proponents had said?

And if they are, where will the power come from if not NYRI?

New power transmission proposals have already arisen since NYRI's demise. At their core, and the core of energy policy throughout the state, are a few simple facts: Most of the power consumed in New York is at the state's southeastern corner, in New York City and its suburbs. Most of the power generated, meanwhile, is far upstate to the north and west. And the means of delivering electricity from one end of New York to another—the state's electrical grid—faces congestion at key points that, in times of high demand, can severely strain the link between producers and consumers.

A national need?

In New York, NYRI's backers argued that the line, which would have carried 1,200 megawatts from suppliers upstate and in Canada, was badly needed. When power is available cheaply somewhere and it can't be obtained because of congestion, it has to be purchased somewhere else at a higher price. Congestion on power lines, mostly those near the middle of the state, cost the state $740 million in 2007, they said, citing a federal Department of Energy study.

In its 2009 energy "report card," the American Society of Civil Engineers, which favors new line construction, said that electricity demand nationwide had increased by 25 percent since 1990, while construction of new transmission facilities dropped by about 30 percent.

The solution proposed by for-profit developers like NYRI's is to build more power lines. But building power lines is the hard part, as energy entrepreneurs across the country have learned.

Relatively speaking, building power plants is much easier, said Ed Legge, a spokesman for the Edison Electrical Institute, a consortium of power companies. Plants tend to be in unpopulated areas, he said, and require government approval for just one site. Power lines, on the other hand, move across vast areas, with countless neighbors. With more neighboring property owners involved, the potential for opposition escalates.

"Somebody's land or somebody's vista is always going to be a part of it," Legge said.

In Northern California, a 600-mile high-voltage line from Lassen to Stanislaus counties died in 2009 after widespread public opposition and a two-year struggle. A 90-mile line between West Virginia and Virginia came online in 2006 after a 13-year approval battle and three years of construction. And a 220-mile line from Duluth, Minnesota to Wausau, Wisconsin took eight years to gain approval and two years to build.

Plenty of power …

Still, the question of whether the state needs new power supplies or transmission lines has some surprising answers. In a draft of its 2010 Reliability Needs Assessment, to be released in final form this fall, the New York Independent System Operator argues that the existing system is sufficient to meet the state's needs over the next decade.

The ISO, a not-for-profit corporation responsible for facilitating energy trading and overseeing the state's electrical grid, cites state energy efficiency programs that are projected to save a total of more than 13,000 gigawatt-hours by 2018. Moreover, the study finds, the effects of the recession in 2009 alone reduced the statewide peak demand forecast for 2011 by 1,400 megawatts. In a separate report, the ISO said energy usage was down 4.1 percent statewide from 2008 to 2009, and down 3.2 percent in New York City.

For its part, Con Edison maintains that worries about the power supply and intrastate transmission system are misplaced. (The utility opposed NYRI, questioning the line's cost-effectiveness and calling it a bad deal for ratepayers.) The utility, spokesman Bob McGee said, is required to have a capacity far in excess of the maximum forecast load – and it has agreements in place with large industrial customers that allow them to shift their power consumption to other sources—and alternative transmission systems—during high-demand periods.

Focus on transmission, Con Ed says, may be misplaced anyway. Getting power to users in the city generally requires three steps: Generating it, transmitting it from the source to the local system, and then distributing it locally. In the Queens blackout of July 2006, in which tens out thousands of customers were without power for as long as nine days, a heat wave caused unusually high demand—and it was the distribution system, the last link in the chain, where equipment malfunctioned and failed. A project like NYRI would have affected the second link—the transmission from generation to distribution.

Plenty of power … for now

But the resilience of the current system depends on a status quo that might not last. First, the ISO says that the declines in consumption will probably be temporary. And second, while the forecasts say the current grid should be adequate over the next decade, those forecasts rest on a few assumptions.

Most critically, the study assumes that the controversial Indian Point Energy Center, a nuclear plant less than 50 miles north of New York City, remains in operation—a less-than-certain proposition considering the level of opposition to the plant among local civic groups. Without its two generating units, the study found, the statewide energy system's reliability would be far below required thresholds. The risk of blackouts, in other words, would increase dramatically.

And hypothetically, other power plants located in or near the city could someday trigger enough opposition that they'd be faced with closure, further imperiling the city's power supply. Or, as the ISO notes, older plants could be forced by stricter environmental laws to make so many equipment upgrades that their operators decide to shut them down instead.