The latest reports on wind-generated electricity in Pennsylvania and New Jersey equate the clean-air impact to pulling thousands of cars off the road.

That's certainly enough vehicles to assemble one impressive motorcade to Washington and lobby for congressional action on extending tax credits viewed as critical to expanding wind power.

The smart, 20-year policy of providing a 2.2-cent-per-kilowatt-hour tax credit for electricity produced by large-scale wind turbines faces a year-end expiration deadline. A similar credit applies to developing offshore wind-driven power - facilities in place in Europe and elsewhere, but which have yet to be launched off the U.S. coast.

Were the credits' renewal to come together in Congress as part of a deal to avoid looming federal budget cuts, they would be a mere footnote in the fiscal-cliff drama, amounting to a $5 billion item over the next decade. Yet, wind-energy tax breaks support an estimated 75,000 jobs nationally - including a foothold in the Philadelphia region.

The Spanish turbine manufacturer Gamesa employs hundreds at the old U.S. Steel site in Bucks County. The firm's presence has given the state a bigger stake than most in the tax-credit debate. Indeed, Gamesa's Pennsylvania workforce could face 20 percent cutbacks unless the provisions are extended.

Even the uncertainty over the renewal over the last few months has hampered investment in new wind-energy projects, given that wind farms take 18 months to bring to market.

It's a hopeful sign that a U.S. Senate committee in August voted to extend the incentives. However, there has been some pushback in the House - with Rep. Joe Pitts (R., Pa.) among those favoring the credits' end.

It's the view of Pitts and other critics that "wind energy is prepared to compete on its own." But advocates for the tax credit make a compelling case that, with only 3 percent of U.S. power generated by wind-energy systems, the nation still has a long way to go in developing a source of electricity that's not only renewable but also pollution-free.

With states like New Jersey increasing their utilities' required share of renewable energy, the modest federal subsidy of wind-generated power plays a key role in reducing smog and minimizing the extent of climate change.

Fortunately, Pitts has been a lone voice in his state's delegation on this issue. Better that Congress heed the call of environmental groups supporting the wind-energy tax credit. As one activist urged, "Don't throw wind power off the fiscal cliff."