Tuesday, September 29, 2009

Carbon Dioxide, and what to do with it

Last week, I attended the carbon sequestration conference in Gallatin Gateway, just a short distance from Bozeman and from Montana State University, home of the Big Sky Carbon Sequestration Partnership.

The topic of the conference was on trapping carbon dioxide in subterranean deposits of rock or saline formations (geologic sequestration) and in soils and trees (terrestrial sequestration).

The need for carbon sequestration is from energy production. When fossil fuels are burned, they are oxidized to carbon dioxide and water (as well as nitrogen oxides (NoX), sulfur dioxide (SoX), volatile organic compounds, and heavy metals), producing significant amounts of energy--and carbon dioxide.

We produce energy, beneficial to us, and carbon dioxide, not good for us. The US Department of Energy, through regional sequestration partnerships, is researching the disposal (trapping, sequestration, storage) of CO2.

Our Big Sky Carbon Seq Partnership (BSCSP) says that "carbon sequestration is the capture and storage of carbon dioxide that would otherwise be emitted to the atmosphere. Greenhouse gases can be captured at the point of emission or they can be removed from the air by plants."

The process is most often referred to as CCS--carbon capture and storage. The term "storage" is a misnomer; storage implies that we'll want to access something later. We mean, by sequestration, to dispose of the carbon by trapping it. The goal is to get rid of the carbon, not to store it and retrieve it later.

The biggest questions for me were about liability for leaks of CO2, changes in chemistry of receiving waters or rock (when you add CO2 to water, carbonic acid is created. It's a weak acid, admittedly, but the chemistry changes.) I'm also concerned about the ownership of the CO2. It's released by energy production, can be trapped or collected, then pressurized and transported via pipeline to a receiving site, and pumped underneath the earth and 'sequestered'. But who owns the CO2?

The study of sequestration is most important because we'll be using fossil fuels for some time, even though we're getting better at diversifying our energy profile to include renewable energy sources that don't combust fuels and release CO2, like wind, solar, and wave energy. Sequestration will be valuable because the goal worldwide is to reduce carbon emissions, so we'll need to trap/sequester/bury/store the carbon.

Montana is being eyed as a recipient of CO2 by Canadian provinces, coal producers and coal plants in the state, and by other states. Before we accept carbon and experiment with trapping it, I'd like to know that we'll not be changing our ground and water chemistry by injecting CO2 into valuable Montana land and waters. I want to know about ownership and liability and long-term 'storage' responsibilities. What about injecting CO2 into subterranean deposits that shift in earthquakes? What happens to our most precious and limited resource, water? What about geologic deposits that underlie multiple jurisdictions (for instance, the Williston Basin underlies Alberta, Saskatchewan, Montana, North and South Dakota. Who can inject into that formation, and what's the liability for the other entities?)

I spoke with a representative of the Environmental Protection Agency at the conference. I asked what the EPA's policy was for protecting waters that aren't US Drinking Waters. "There isn't one," she said. "Well," I said, "Montanans in arid regions use water that's highly salinated and mineralized for stock water for cows, for domestic use, sometimes for ag operations. We need those waters protected, too."

Presenters admitted that the technology and processes are in their early stages. Some of the comments included, "If we don't understand the subsurface pretty well, we'll be in trouble." "We may need to drill wells to release pressure. We may need to produce water." This goes to a comment of mine that nature hates a vacuum, and nature hates high pressure and will try to equalize that pressure. When gas or liquid is pumped into a formation, pressure changes and other elements will be forced through or out of the formation. Another: "The costs of carbon sequestration have been woefully underestimated." With regard to pumping CO2 into deep saline aquifers, my concern is this: water has a limit for dissolved solids and gases. The more metals or saline or other gases in water, the smaller the potential for that water to accept and dissolve another element. One presenter said, "No one's drilled down to find out what the salinity is [of deep saline formations]." Another proposal is to pump CO2 into porous rock--into its pore space. Although we can identify types of rock, it's difficult to say how much or how consistent its pore space is. One presenter said, "No one has gone prospecting for pore space, so no one really knows."

My closing thoughts are these:
+ We can do better with energy production. We're moving in that direction. Just as we know we need to diversify economic portfolios, we need to diversify our energy sources to include renewables. Let's use all the solutions available to us.

+ If we don't produce vast amounts of CO2, we don't have to figure out how to collect, transport, trap, and forever monitor it.

+ Developing nations want cheap and easy fuels, too. That means coal and oil. With a limited tolerance in the atmosphere for a certain amount of CO2, NoX and SoX, then we cannot all emit those gases.

+ We are creative. We can find ways to more responsibly use all our forms of energy.

I'll keep working for a better energy future for Montana, for resource protection of our waters and land, and for cheap, reliable power. I'm an energy user, too.


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