With an estimated 14 million Americans unemployed, both oil industry and environmental interests are increasingly using jobs as their No. 1 message -- often pitting economic projections from less-than-impartial sources against one another.

The job-creation debate rarely plays out in a head-to-head fashion between fossil fuels and renewables, but the names Keystone XL and Solyndra have emerged as boldfaced targets for opponents of their respective energy sources. While green groups take aim at industry vows of 20,000 jobs to be created by the XL pipeline, which would nearly double U.S. imports of Canadian oil sands crude, the GOP blasts the bankrupt solar firm as a symbol of the hollow promise of clean energy jobs.

When it comes to the Keystone XL project, fully objective jobs data is often in short supply. The resulting dissonance between opponents' and supporters' claims was illustrated in living color earlier this month at a State Department public hearing on the pipeline, when union members booed their traditional allies in the environmentalist camp who argued against the XL link -- only to signal alliance with members of the Occupy movement on the importance of job creation, despite the fact that those protestors also opposed the pipeline.

"We've often seen industry trying to get unions to go along with them on anti-environmental positions by threatening their jobs," the House Energy and Commerce Committee's top Democrat, Rep. Henry Waxman of California, said in a recent interview about labor support for the 1,700-mile pipeline. "Most of the unions are catching on."

The four major pro-XL unions that have signed pacts to help build the pipeline join the company behind the project, Alberta-based TransCanada Corp., in touting estimates that it would create 119,000 total jobs, including 20,000 direct posts. Those projections, derived from a TransCanada-commissioned study by the Texas-based Perryman Group consulting firm, were savaged by the Global Labor Institute (GLI) of Cornell University in a report frequently cited by environmentalists seeking to dissuade the Obama administration from approving the pipeline.

Citing data that TransCanada provided to the State Department, which expects to rule on the XL link by 2012, the GLI offered "no more than 2,500-4,650 temporary direct construction jobs" as a more appropriate estimate of the pipeline's impact. GLI also warned that the pipeline could leave a long-term negative jobs footprint, in part through a "chilling effect" on the greener projects funded through the White House program that backed Solyndra.

The suggestion that Keystone XL could be a "job killer" met with aghast alarms from its backers. "How is a project that's going to have 1,700 miles of pipe not going to be a job creator, regardless of what the numbers are?" Cindy Schild, the American Petroleum Institute's (API) refining manager, said in an interview. "There is no way that building infrastructure is a jobs loser."

Economist M. Ray Perryman, of the eponymous firm behind TransCanada's 2010 jobs estimates, circulated a scathing rebuttal that blasted GLI as motivated by "clearly advocacy rather than objective analysis."

"Given the state of renewable energy technology, it is unlikely that it will displace a substantial segment of global hydrocarbon demand (particularly refined petroleum products) in the near future," Perryman wrote in a specific rejoinder to GLI's claim that the pipeline could kill clean-energy jobs.

Which side is using more correct numbers? The answer may not matter to the unions already backing the pipeline, such as the Laborers' International Union of North America (LIUNA) and the International Brotherhood of Teamsters.

A LIUNA spokesman did not return requests for comment on the jobs debate but forwarded E&E Daily a copy of Perryman's reply to GLI. And the Teamsters' chief economist, Jim Kimball, said last month that "I'm not really sure I worry about the jobs estimates.

"Jobs are jobs," Kimball explained at a discussion of the pipeline hosted by the Woodrow Wilson International Center for Scholars. "We would support this project even if these job estimates are half of what they are."

Oil versus renewables?

The employment tussle encompasses quantity as well as longer-lasting job quality -- a front that brings green jobs, such as the 1,100 lost amid Solyndra's flameout, back into the conversation.

For GLI associate research director Lara Skinner, the long-term durability of clean-energy jobs make them a more viable focus for unions than more temporary posts such as those created constructing crude pipelines.

"The jobs that are going to be created [from XL] are not insignificant in any way, especially to people who are going to get those jobs," Skinner said in an interview. "We want jobs, but we don't want jobs at any cost, and we really do have to have a more comprehensive look at their broader social and environmental impacts."

U.S. EPA chief Lisa Jackson is likely to take just such a broader look today during a Denver appearance to discuss Colorado's implementation of a bill converting coal-fired power plants to more renewable generation sources. Yet the oil industry is equally eager to fight for its priorities under a jobs banner.

"We're pretty confident in what this project will provide to American families as far as impacts on employment immediately," said Schild of API.

Schild also seized on an argument often employed by Keystone XL backers: that unlike renewables, the pipeline is seeking none of the direct government loans or grants that both the Obama and Bush administrations have given to clean energy.

"For the green movement to make a jobs argument vis-a-vis established suppliers of energy, it really is a fools' game," venture capitalist Bill Frezza, a fellow at the conservative Competitive Enterprise Institute think tank, said in an interview. "If I were them -- I don't believe in subsidies, but if I did -- I'd be arguing that money should be going in early-stage [clean-energy] research, not in commercial scale."

Frezza acknowledged that federal supports hold appeal for "green companies, brown companies, companies of every stripe," adding that pipeline operators such as TransCanada would employ technology to "build a pipeline that would create no jobs" if it were available.

Ultimately, the allure of the jobs that would be created by the XL link -- no matter their number -- are neither driving a lasting wedge in the labor-green alliance nor impeding conservationist organizing against the pipeline.

The co-director of the student-centric environmental group Energy Action Coalition, Maura Cowley, joined dozens of fellow anti-Keystone activists in an overnight wait to secure testimony time at this month's public hearing on the pipeline. By her side for those hours were LIUNA members pushing for XL's approval, Cowley said in an interview, but their disputes were far outweighed by common ground.

Between the union members and the green-minded students, she recalled, there was talk of "how we're going to continue to work together ... that even if we're on different sides of the pipeline, we're still in the 99 percent."

Click here to read the Perryman Group's economic study of Keystone XL.

Click here to read the Cornell report disputing the Perryman data.