The solar industry is growing fast — which puts in that awkward position where it can lay claim to some very big numbers but also very small ones. Mother Jones reports that the solar power produced in the U.S. in the past decade has "leaped 139,000 percent." That’s despite the fact that in 2013, solar power only made up 0.2 percent of the energy generated in the U.S., whereas coal produced 39 percent, according to the U.S. Energy Information Administration.

For Vox, Brad Plumer reports on another big number: the non-profit Solar Foundation says 174,000 people work in the solar industry. That means, he says, that the solar industry has created so many jobs, from solar panel manufacture to installation, that it now employs just about as many people as the coal industry does.

Plumer’s comparison pits Solar Foundation's numbers against the 80,000 who work in coal mining, plus the number of people involved in coal transportation and coal power plants. Those later numbers, he notes, are based on 2006 estimates, so solar power could employ even more since many older coal plants have closed since.

On the face of it, this may seem like a win for solar power supporters. But Plumer points out that the comparison highlights how labor-intensive solar power is compared to other sources. He writes, "If the world wants to avoid drastic global warming, we'll need to replace dirtier sources of energy, like coal, with cleaner sources — solar, wind, nuclear, say — and fast. And the higher cost of solar is a real impediment to doing so."

However, the coal industry has a lot of indirect costs—health and environmental impacts—not typically folded into such comparisons. "These costs don't show up on electricity bills. Instead, they're dumped on the broader public, in the former of shorter lives or higher hospital bills," he writes.

The jobs number may be fuel for political debates, too. The Solar Foundation reports that the tiny solar industry has provided 1.3 percent of all the new jobs created in the U.S. since the 2013 census. That's a small number—but it could indicate that the solar industry’s clout is growing just as fast as its share of energy production.