The Southern Company (SO), Alpha Natural Resources, Inc. (ANR), Peabody Energy Corporation (BTU), Kinder Morgan Energy Partners LP (KMP): A Comeback for King Coal?

Natural gas prices have enjoyed a phenomenal run so far this year. After suffering from severely depressed prices over the past year and a half, natural gas has surged more than 20% this quarter, as chilly temperatures have lingered for longer than expected.

For the week ended March 22, natural gas rose by as much as 1.3% after a report by the U.S. Energy Information Administration showed that inventories fell by 95 billion cubic to 1.781 trillion cubic feet.

Natural gas producers are obviously rejoicing. But rising gas prices are also a boon to coal companies, because coal is one of natural gas’ biggest competitors for U.S. electricity generation.

Does the natural gas rally signal a resurgence for King Coal? Or are coal’s best days behind it?

A rough year for coal
Over the past year and a half, an unmistakable trend among utility companies was the switch away from coal and toward natural gas as a fuel source for powering their plants. For instance, in the first quarter of last year, when gas prices were less than $3 per Mcf, several utility companies announced plans to curtail or retire coal-fired plants in favor of natural gas-powered facilities.

For instance, American Electric Power Company, Inc. (NYSE:AEP), one of the largest utilities in the country, announced that it would eliminate roughly 5,000 megawatts of coal-powered capacity by retiring five of its 25 coal plants and shutting down coal-fired units at some of its other plants. Early last year, the company said it expected coal to generate just half of its total power by 2020, compared with 67% in 2011.

Other utilities followed suit. The Southern Company (NYSE:SO) recently revealed that it burned more natural gas last year than coal for the first time in the company’s 100-year history. The share of coal it used for total power generation declined from 70% to 30%, while the natural gas share rose from 11% to 47%.

Not surprisingly, coal’s share of U.S. electricity generation plunged to 37% last year, down from 42% in 2011. Meanwhile, the natural gas share increased to 30%, up from 25%. But now, with gas prices sharply higher and coal prices still depressed, coal is starting to look a lot more attractive as a fuel source — especially when you take a step outside the U.S. and consider global opportunities.

Global demand for coal set to increase big-time
As Fool contributor Tyler Crowe recently noted, the global outlook for coal is much brighter than the domestic one for two important reasons.