On the campaign trail, President Barack Obama pledged to create millions of new, not-for-export "green collar" jobs as part of a long-term strategy to reshape the U.S. economy.

In testimony before Congress, U.S. Secretary of Labor Hilda Solis said "green jobs play an important role in our economic recovery. The promise of green jobs is not only to help re-start the economy and put Americans back to work, but also to help make America more energy independent."

But recognizing a green job from any other variety is not always easy.

Joan Evans, director of the Wyoming Department of Workforce Services, said some jobs are relatively simple to classify as "green;" as, for example, a person trained as a wind turbine technician who actually works on a wind turbine.

But what about an electrician who works on a wind turbine only during the time it is being erected, or a construction worker with green-building skills who spends most of his time on traditional jobs? "That's where it gets a little bit fuzzy," Evans said.

Tom Gallagher, manager of the Wyoming Department of Employment's Research and Planning Section, said in view of the Obama Administration's push to create green jobs, deciding which jobs are green has important practical consequences.

"It soon became apparent that there's a very high political valence on this issue because it means access to funding, it means access to training funds," he said.

One approach to thinking about green jobs might be to identify green industries. Accordingly, farm state senators might push for more funding to the ethanol industry.

But Gallagher said a countervailing argument might be that ethanol requires too much in the way of petrochemical inputs to be considered green, or that ethanol might prompt some countries to clear too many forests to plant crops for ethanol.

Similar debates have broken out about "clean" coal and nuclear energy.

Gallagher said perhaps a more useful way to think about green jobs is in terms of function, recognizing that few jobs are purely green.

"You may perform a green function in 20 percent of your job, and the other 80 percent is what you'd usually do," he said.

Evans said the Department of Workforce Services' working definition of green jobs encompasses renewable energy, energy conservation and energy efficiency.

She said under the Workforce Investment Act, from which her department derives much of its job training money, there is no separate component for green jobs. However, with a greater emphasis on green jobs, she expects that more requirements documenting the creation of green-collar jobs will be on the way.

The Department of Labor suggests green jobs might be related to renewable energy infrastructure, energy efficiency home retrofitting, biofuels development, and advanced drive train/vehicle development and manufacturing. It plans to use $500 million for, among other things, job-training projects that prepare workers for careers in energy efficiency and renewable energy industries.

It's not clear how much we really need to know about green jobs, Evans added. "The critical thing is that we train people for the skills that employers need, green or not."

In a Washington state study published earlier this year, direct employment in green industries was calculated at only 1.6 percent of all private-sector employment.

The green economy was defined as rooted in industries and businesses engaged in energy efficiency, renewable energy, preventing and reducing pollution, and mitigating or cleaning up pollution.

Business Editor Tom Mast can be reached at tom.mast@trib.com, or call 307-266-0574. Or check out his "Two Bits Worth" blog at tribtown.trib.com/TomMast/blog.