Throughout the 20th century, coal supplied the bulk of America’s electricity. It was coal, by and large, that kept our lightbulbs, radios, laundry machines, dishwaters, TVs and computers humming along, and coal that provided miners up and down Appalachia with well-paid union jobs. Coal was central to the American economy. No other source of electricity came close.

That started to change around 20 years ago when new advances in drilling opened up vast reserves of cheap natural gas. Fracking allowed drillers to crack open hard, shale rock, and horizontal drilling allowed them to tap the hard-to-reach stores of gas buried underneath. Suddenly, gas was cheaper than coal, and power companies began replacing aging coal plants with new gas generators. In 2015, gas overtook coal as America’s primary source of electricity.

Because gas-fired power plants produce around half as much carbon pollution as coal plants, the shift was heralded as a triumph for the climate. The oil and gas industry touted gas as a “bridge fuel” that would allow the United States to cut pollution while scientists and engineers developed cleaner, cheaper sources of power.

That bridge, however, has proved shorter and more rickety than many in the oil and gas industry expected. Wind and solar are now as cheap or cheaper than gas in most places, leading some analysts to suggest that the United States is about to hit “peak gas.” And in a few years, it will be cheaper to build new wind farms and solar arrays than to keep existing gas-fired power plants online, forcing utilities and ratepayers to eat the cost of new gas generators being built today.

Governments are hastening the shift to renewables with tax breaks and clean-energy mandates, as calls to wean off gas grow louder amid revelations that the so-called “bridge fuel” may not be as clean as advertised. Researchers have shown that pipelines and drilling sites are leaking huge sums of unburned natural gas, which consists mostly of methane, an extremely potent heat-trapping substance. The leaks are so pernicious that, in the final accounting, natural gas may actually be as bad for the climate as coal.

That brings us to this month’s issue: the future of natural gas.

We looked at how companies like Shell are betting big on plastics to make up for lost revenue as demand for gas wanes. We asked what landowners can do about aging gas pipelines buried in their backyards. We investigated how a power company in California, in attempt to go green, is sourcing methane from cow manure and what that means for the people who live near feedlots. And we looked at how a Pennsylvania gas utility is trying to stop Philadelphia from curbing the use of gas in buildings. We will publish articles, photos and videos on these topics in the coming weeks.

It took more than a century for natural gas to unseat coal as America’s reigning power source. Renewables will dethrone gas in mere decades. The transition of power is already underway.

“Obsolescence is the very hallmark of progress.”

Henry Ford II