A vision is developing, as we see electric Teslas, Bolts and bikes scooting through traffic, of how we might squeeze dirty fossil fuels out of our transportation system. That goes for buildings, too: Nearly a dozen cities in California have largely banned gas burning in newly constructed buildings, and the moment nears when gas bans will jump to other states.

The foundation for cleaner cars and cleaner buildings will be a cleaned-up electric grid to power them, and the country is making headway there. But that’s just one step. The production of the vital materials on which human society is built — iron, steel and cement — is responsible for more than 15 percent of the global greenhouse emissions that are overheating the planet. Many other industrial processes use dirty fuels, too, and we have barely begun thinking about how to clean all that up.

The task is beyond urgent, not that you would know it from listening to the nonsense spewing from Washington. But state governments led by Democrats are pushing forward, with Governor Polis and a handful of other governors and legislatures in the vanguard. A Republican senator from Colorado, Cory Gardner, turned up at the announcement to lend his support.

Why would a steel mill install a solar power plant next door? The company cares about going green, certainly, but this is also about money.

We do not know the exact price the company will pay for its solar power — that is a secret under Colorado law — but we do know that the cost of large-scale solar farms has plummeted. To improve its finances, Evraz seems to be locking in low-cost power for the long term.

Yes, solar projects like this still receive federal subsidies, but those are scheduled to be phased down. We seem to be heading quickly toward a world where solar panels, unsubsidized, will be the cheapest way human beings have ever found to produce electricity.

The steel plant here, founded in 1881 and known for most of its life as Colorado Fuel and Iron, is the mill that built the American West. Most of the steel rails that bound the region to the rest of the United States came out of the mill, and high-quality rails are still among its most important products.