Over the years, there has been nothing consistently cheaper than coal as a fuel.
So, why is coal more expensive today than yesterday, or even just recently?
The EPA has set emissions standards, not only on brand new coal plants but old ones as well, so high that it has become too expensive to meet them.
For example, scrubbers on the exhaust stacks could remove 80% of the particulates, and scrubbers are relatively cheap to install. But the EPA wasn't happy with an 80% reduction in particulates, it wanted 90%. That extra 10% reduction requires completely redesigning the plant to achieve - therefore it is cheaper for the utility companies to close the plant. That reduces demand for coal, and more coal mines close.
But one would think the electric companies will eventually build new plants to take advantage of the cheap coal. Alas, the utility companies can't trust government - the EPA - from wanting a 95% reduction in the future. Or a reduction of another form of pollution, like CO2 emissions. Companies aren't going to invest in infrastructure that might only be usable for 5 years, not the 50 year life they need to make it a worthwhile investment.
Just last year, the EPA stated no more regulations were needed, but a new study was released this year, and the EPA is looking at introducing more regulations next year. The emissions target everyone designs these plants for keeps getting changed. It's become impossible to design anything that might last 10 or even 15 years before it becomes obsolete by government decree. Companies need life spans of plants of 50 years. That's why the EPA used to grandfather existing plants from new regulations, that's why your 1990 car can pollute more than your 2015 car. But recently the EPA has been targeting the old plants as well. It's the targeting of the existing plants by the new regulations that's making it impossible to build new "relatively clean" coal power plants, not the cost of buying the coal.
I'm not going to debate whether having coal power plants is wise or not, but I just wanted to point out why coal power plants are a dying breed. The price of "buying" coal is NOT rising as much as the price of "burning" the coal is.
And to take this one step further and slightly off-topic. When regulations force a closure of a manufacturing plant in a big city, the local economy gets hurt. But in the big cities, there are other manufacturing plants, other means to fund the local economy, and eventually something else replaces the plant that's been closed down. But in small cities and towns, the local economy gets destroyed, nothing ever replaces it, and the town dies.
Look at Detroit, the closure of the first plant barely affected it, but as more and more plants have closed, it's local economy has been affected. Detroit is less than half the size it was 20 years ago. Homes in some neighborhoods values have fallen from $100,000 in value to less than $10,000 in value. And it was a much larger city than it is today. I'm not even sure we can blame its decline to regulations. But the decline of the coal industry can be blamed on regulations - and coal mines are NOT located near any large cities.