NY Times gives the mayor credit for some of the past successes:

Conservation measures, large and small, figure prominently in the task force's game plan. The Green City Buildings Act, signed into law last October, requires large nonresidential projects to meet environmentally sound energy-efficiency standards, and the mayor has required the same of government construction. The city replaced refrigerators in some 180,000 subsidized apartments with models using 75 percent less energy than older models, and even switched pedestrian traffic signals from old-style bulbs to much more efficient light-emitting diodes.

The biggest undertaking is an effort to decrease energy demand, especially at peak times, like the air-conditioned days of summer. One key initiative is Con Edison's plan to reduce peak demand by 675 megawatts over three years by using financial incentives to entice consumers to cut back on peak days, which they can do by turning off some lights and equipment. The goal is lofty and by no means assured.

That last line is the key - simply passing legislation without intense follow-through will result in failure. The city along with business, environmental and local citizen groups should encourage businesses to sign-up for this peak use incentive program as well as other energy conservation and efficiency upgrades to do their part to stave off the need to construct another power plant.

Moreover, the city should encourage the upgrading of NYC's aging power generation plants:

In addition, the task force needs to find some way to encourage more investment in generating capacity. Two factors above all have discouraged Wall Street. One is deregulation. Whatever its other virtues, deregulation has made markets more uncertain. The other is the failure in recent years of several large energy concerns, including Enron. This has also made investors and lenders skittish.

One way to address these fears is to encourage retailers of energy, like Con Edison, to commit to longer-term contracts that promise future returns, as happened with the SCS Astoria 500-megawatt plant in Queens.

I would also like to see the Energy Task force start to tackle issues beyond electrical energy - like transportation and home heating, which are two of NYC's most voracious energy consumers of non-electrical energy.