CCS uncertainties

One of the themes I keep returning to, on this site and in meatspace, is “respect for your own ignorance”. That’s shorthand for understanding the limits of your (or humanity’s) knowledge and then restraining yourself from acting on assumptions when you don’t have the knowledge to back up those actions or decisions.

On a personal and trivial level, I don’t do major plumbing work in my house because I don’t know enough to get it right with any real certainty. Sure, I can change the cartridge in a faucet and do other minor low level stuff, but anything that requires the use of a propane torch, for example, sends me to the phone to call a professional. Because of my background and long-time hobby interest in computers, I’m much more comfortable building them, taking them apart, and generally doing “screwdriver and software driver” work. (But don’t tell anyone; it’s a pain being known as the “go-to guy for computer stuff” in your neighborhood.)

In terms of peak oil and climate chaos, this general philosophy makes me conclude that we should have been doing much more to transition away from oil and reduce our CO2 emissions decades ago, even when our situation was far less certain than it is now. And now that both of those situations are far more urgent, our decisions have shifted from “should we do anything about this” to “which X of our Y possible solutions to these problems should we pursue, and how should we fund them”. Of course, the proximity of peak oil and serious climate chaos impacts only makes these decisions all the more difficult and important; we’ve long passed the point where we could rely on gradual, comfortable, and low risk solutions. The higher the stakes in the decisions we’ve now forced ourselves to make, the more important it is that we “respect our own ignorance” and not make too many mistakes.

All of which leads to back to one of the great assumptions that many people seem to be all too willing to make: That sequestered CO2 will remain sequestered “forever”. A pretty decent treatment of this issue is in the article Nature’s underground carbon stores aren’t rock solid:

Carbon dioxide stored underground in nature eventually ends up mainly in fizzy water, not rocks — and that could have implications for artificial carbon capture and storage projects.

A new study by British, Canadian and U.S. researchers, published in Thursday’s edition of Nature, sheds some light on the conditions that allow carbon dioxide to be safely stored underground for thousands or millions of years, as well conditions under which it might leak back out into the atmosphere.

Carbon capture and storage projects have been touted as a possible way to reduce the emission of carbon dioxide into the atmosphere and reduce climate change, but the research is still in the very early stages.

“We haven’t figured out as a planet yet how to do this,” said Barbara Sherwood Lollar, a University of Toronto researcher who was one of the co-authors of the study.

…

In the past, researchers have suggested that the carbon dioxide could end up dissolved in water — turning it into sparkling water or club soda — or incorporated into minerals such as carbonates and limestone, but did not know which would be dominant and under what conditions.

University of Manchester doctoral student Stuart Gilfillan, who led the study with his supervisor Chris Ballantaine, decided to examine nine natural gas fields in North America, China and Europe. He and his colleagues discovered that carbon dioxide was largely dissolving into the water within a narrow, slightly acidic pH range, and less than one-fifth of the carbon dioxide was being incorporated into solid minerals.

This could be interpreted as bad news by some people, suggested a commentary by Heidelberg University researcher Werner Aeschbach-Hertig published in the same issue of Nature.

“Clearly, mineral trapping is the preferable pathway, as it promises to store the carbon over geological time scales,” he said.

Sherwood Lollar acknowledged that carbon dioxide dissolved in water and bottled up underground can come up to the surface in different ways, such as through natural gas wells and other holes drilled by humans as well as through natural faults.

“So there are many places where CO2 gases bubble up through water naturally. We call them spas,” she said with a laugh. She later clarified that such natural discharges are on a small scale and the implications for leakage from engineered carbon storage sites would require further study.

Please see the article for a bit more detail.

We’re making a lot of collective decisions right now about energy and environmental issues, and some of them orbit the general question of what the US (and other countries) can and should do about their coal-fired electricity generation. The US alone burns over a billion short tons of coal per year to produce 50% of our electricity and almost exactly one third of our CO2 emissions, over 1.9 billion metric tons, related to energy consumption. That’s a big mess by any measure.

What would it cost to replace all that generation capacity with some mix that was not just cleaner than what we have now, but clean enough that we wouldn’t need to immediately start to replace it again with something even cleaner? (And whatever solution will also have to take into account things like shifting patterns of water availability for any technology, like thermoelectric plants, that typically has a high cooling water requirement.)

If replacement is out of the question, then what would it cost to retrofit a large portion of those hundreds of existing coal plants with CCS technology? And that retrofit would have to include not just on-site capture hardware, but the infrastructure to transport the CO2 to a geologically suitable and politically palatable site, sequester it, and then monitor it forever.

And what do we do if we decide to start rolling out CCS, based on the assumption that we know how to sequester that amount and flow rate of CO2 forever, spend a large pile of billions of dollars on the effort (money that could have built wind turbines or solar panels or geothermal plants, to name just three possible alternatives), and find out 20 years into the conversion that some non-trivial portion of the sites have begun leaking?

No matter how we slice and dice the details, we’re left with a nasty problem. We have to clean up our electricity generation. There is no other option, simply because we can’t get to the needed level of emissions cuts without doing so. That means dealing with the coal issue, which in turn means deciding how large a bet we want to make on our ability to make CCS work on the needed scale.

Such society-wide decisions are made in anything but a vacuum; as much as some people decry the role of economics in the process, consider what happens when politics comes into play. Such should-be trivialities like which party is in power or where the coal plants are located (as in which Congressional district or key electoral states) could become key contributors to which path we choose.

This post sounds more cynical than I intended it to, and I apologize for that. What I’m really appealing for, aside from a thorough examination of CCS technology before we bet the farm on it, is that more of us stop contributing to the polarization in the energy and environmental arena. We have to show the courage to “just say I don’t know” on some issues. There’s a lot of gray area in between the black and white extremes, and we shouldn’t be afraid or ashamed to set up camp there, resist the screamers at both ends of the debate, and respect our own ignorance until we have more facts.

And speaking of assumptions–as I type this the news feeds are all reporting the latest updates on the shooting in Binghamton, NY. My wife and I lived in Binghamton from 1979 until 2004, and it’s a perfect example of the kind of small city that people on the news always describe by saying “things like that don’t happen here”. Or so we and they assumed.

My heart goes out to everyone in the Parlor City.