Coal Mines Provide Enticing Green Energy Source

Jun 14, 2013

New methane power generation facility at the Oxbow Mine at Elk Creek.
Credit Credit Kathy Browning - Flickr

One local company is already taking advantage of methane capture at coal mines. The Aspen Skiing Company last year, invested in a project that generates energy from methane at a mine near Paonia.  Their trailblazing will set the stage for other groups to try out similar projects. Aspen Public Radio’s Ellis Robinson reports.

Environmentally-forward thinking has long been a part of Aspen Skiing Company’s brand and business strategy.

“If we really want to be operationally green, we’ve got to figure out a way to generate a lot of clean power.”

That’s Auden Schendler, Vice-President of Sustainability for the Aspen Skiing Company, or SkiCo.  He’s been at the forefront of SkiCo’s effort to become operationally green. To show his dedication to that cause, last year, he was at the ribbon cutting ceremony for a new project at the Elk Creek Coal Mine, in Somerset, Colorado, where they cranked up the new methane power generators.

The project brought together a unique group of bedfellows. SkiCo’s partnered with Oxbow Mining Company and Holy Cross Energy to capture methane coming out of the Elk Creek mine and turn it into electricity. It’s arguably the greenest thing SkiCo has ever done. Again, Auden Schendler.

“You’re saying let’s delete methane and replace it with CO2. Methane being vastly more potent as a greenhouse gas, that ends up being a net positive in terms of reducing emissions.”

Even though Methane is a very simple molecule, it’s powerful. It consists of a carbon atom in the middle, and four hydrogen spokes pointing outward. Methane very efficiently absorbs the heat waves radiating out from earth’s surface towards space.  A molecule of methane, on average, traps 200 times more heat than the same amount of  carbon dioxide.  In the context of global climate change, think of CO2 as the much lesser of two evils.

“We’re fracking for natural gas all over western Colorado.  At the same time the mines are venting natural gas, why not use it?”

Those mines Schendler is talking about are coal mines. By capturing the methane from coal mines that otherwise would be spewed out into the atmosphere as potent greenhouse gas, SkiCo is helping reduce the overall greenhouse warming potential that is the consequence of coal mining. And, it’s turning that methane into electricity:

“You could make as much power, as much electricity as the ski resort uses year round.  That’s a huge amount of power.”

Where there is a coal seam, deep in the earth or in the side of a mountain, methane can be found.  Though coal and methane are not inseparable, the two always show up to the party together.

Traditionally, coal miners vent the co-mingled methane gas to the atmosphere, because not doing so is “..extremely dangerous in an underground mine. A major cause of explosions, fires, accidents, and death.”

That’s John Wheaton, a hydrogeologist with Montana’s Bureau of Mines and Geology. He explains the geologic process of producing methane alongside coal. “To form coal, you start with a massive, massive amount of organic material.”

Picture a pre-historic swamp... with algae, fish, fern trees, bugs.. all these organisms living, and  then dying in the swamp. These dead life forms sink to the bottom and stack up and up. At the same time, they get buried by eroded earth--- like the rock and dirt running off Aspen Mountain with each year’s snowmelt.

“Bugs are starting to decompose that... chemical and biological reactions are breaking that material down.” Microbes, or “bugs”, are buried alongside the dead plant life and algae, and help decompose the organic material.  This decomposition spun out over geologic time, helped by high pressures and temperatures--from being buried deep underground---results in coal.

But something else is being made too: “There is methane generated in the decomposition during the coalification process....” The same dead plant life being slowly transformed into coal, is also decomposing into methane, deep in the ground at, “a few hundred feet to a couple thousand of feet deep, the coal seams will continue to be broken down by bugs, methanogens will continue to generate methane.”

This process is even on-going---microorganisms are eating up coal and spitting out methane molecules as we speak in active coal mines.

What makes coal and methane such a dynamic duo is how they stick to one another. Because coal is highly porous, methane gets inside of it and easily binds to coal’s surface. And because there are so many pores, there is a whole lot of surface area, and thus a whole lot of methane. “Think of it as a single layer of methane molecules stuck to the coal.”

At high pressures deep underground, methane is quite happy to stay nestled up to all of the surface sites on the coal. But when miners start digging, exposing the seam and releasing pressure, the methane leaks out of the holes and pores of the coal into the atmosphere.  That methane is a safety hazard for miners, but an opportunity for an environmentally-minded company, like the SkiCo Here again is Auden Schendler: “This is kind of what we specialize in at Aspen Skiing Company: Complex projects that are groundbreaking, that are really difficult, and that we don’t always succeed at.”

But unlike some of the failed or abandoned projects SkiCo has pursued in the past, this one seems to be panning out so far, and in a big way. Their coal-mine methane project is currently providing the equivalent of Aspen Skiing Company’s total power needs for the year, which is no small number at 25 million kilowatt hours.

“Think of a kilowatt-hour as dishwasher load of energy, so you could do 25 million loads of dishes”

And that’s a lot of dishes. Or Gondola rides, if you like.