Dynegy

It's not just for coal: Natural Gas-fired power plants could use carbon capture technology, too.

A prominent researcher says it would be foolhardy to abandon plans to siphon off the carbon dioxide from industrial emissions and store it underground. The concept, known widely as “carbon capture and sequestration,” or CCS, has been a slow starter in the U.S. In fact, worldwide, there are only a handful of working projects.

“It never had a chance,” said Sally Benson, following a panel at a major science conference. Benson directs the Global Climate & Energy Project at Stanford University, and is a proponent of CCS — though she says companies that were leading the charge are now “wavering.” She told me that the 2010 UN climate talks in Copenhagen were a turning point; when it became apparent that governments weren’t about to put serious restrictions on carbon emissions, she says investors backed away from CCS, which is still in the pilot stage of development and very pricey.

UPDATE (2/26): A recent poll shows public perceptions of “clean coal” badly eroded from a few years ago, with only 42% viewing it favorably. Matt McDermott’s commentary on the Treehugger blog may reflect the general skepticism:

“Clean coals fall from extremely/very favorable status is likely again the result of questions being raised about its potential (as in, there’s no such thing as clean coal, despite what the industry would have you believe). Prior to 2009 politicians on both sides of the aisle touted clean coal, and still do today, but the voices for it have grown quieter.”

But Benson says even in a rapid retreat from fossil fuels, renewable energy sources and improved efficiency will only get us so far, so fast. We still have to deal with the “inertia” of a world that is still heavily dependent on fossil fuels. “We need to keep it on the table, “Benson told me after a panel at the AAAS annual meeting, which wrapped up this week in Vancouver.

Benson says using CCS at just one (1,000-megawatt) coal plant would have the same effect on carbon emissions as if 2.8 million drivers suddenly switched from their gas guzzlers to hybrid sedans. She says there is “no scientific basis” for fears of a “massive eruption” of CO2 from storage in underground rock formations. Carbon dioxide is non-explosive but high-enough concentrations in the air can be fatal.

CCS has long been associated with efforts to produce power from “clean coal.” But with no coal-fired plants in the state, do Californians even have a horse in this race? Benson says yes.

California CCS Coalition

Most CCS concepts involve siphoning off CO2 from emissions and injecting it deep underground.

“We have a lot of places where we could be capturing CO2 from natural gas plants,” she said, adding that CCS could also be deployed in biofuel production and the manufacture of hydrogen. Natural gas provides the largest single share of electricity in the state, nearly 40%. And some parts of California, notably the L.A. Basin, are still heavily dependent on coal power imported from neighboring states.

Current CCS is confined to a few pilot projects, including the $2.5 billion HECA project to produce hydrogen in California’s Kern County. Benson says one advantage of CCS is that it could potentially make a sizable dent in total carbon emissions with relatively few projects.

Cost is clearly the biggest obstacle, according to Ben Yamagata, with the Coal Utilization Research Council, a technical arm of the coal industry. He says that installing CCS could add anywhere from 30-to-70% to the cost-per-kilowatt of electricity produced by a new coal plant. “That really and simply means that it costs too much.”

Kimberly Ayers

And you thought plastic palm trees had no redeeming value...

A cheap plastic that removes carbon dioxide (CO2) from the atmosphere? “Yes,” says a team of chemists at the University of Southern California’s  (USC) Loker Hydrocarbon Research Institute, led by Nobel Prize winner George Olah. Science Now reports on their work with an inexpensive polymer called polyethylenimine or PEI.

But how to maximize its absorption capabilities? Olah’s team dissolved the polymer in a solvent and spread it out, peanut-butter-style, on fumed silica — you know, like the stuff in those desiccant packets in your electronics packaging (“Do not eat,” by the way).  It’s also used as a stabilizer for lipstick and other make-up.

Here are the geeky details from Science Now:

When the researchers tested the new material’s CO₂-grabbing abilities, they found that in humid air—the kind present in most ambient conditions—each gram of the material sopped up an average of 1.72 nanomoles of CO₂. That’s well above the 1.44 nanomoles per gram absorbed by a recent rival made from aminosilica and among the highest levels of CO₂ absorption from air ever tested, the team reported last month in the Journal of the American Chemical Society. Once saturated with CO₂, the PEI-silica combo is easy to regenerate. The CO₂floats away after the polymer is heated to 85°C. Other commonly used solid CO₂ absorbers must be heated to over 800°C to drive off the CO₂.

Team member Surya Prakash says the polymer could also be used to make vast farms of artificial “trees” that could suck CO2 out of the atmosphere, much like real ones do. Prakash and Olah have been trying to stand the carbon paradigm on its ear for the past several years, exploring it as a positive rather than a negative for the planet. “People tend to think of CO2 as a problem rather than a resource,” he explained. “We want to take CO2, and instead of burying it underground, use it as a raw material, and convert it with alternative energy sources back to fuels and feedstocks.”

Stanford University

Stanford researchers Sally Benson and Jean-Christophe Perrin measure the movement of CO2 through rock samples.

Sally Benson and her lab crew have been giving rocks a very hard time.

The energy resources engineering professor has been heating rock to 122 degrees and subjecting it to the pressure of a hundred atmospheres —  the same pressure present at a half-mile or so underground — to see how carbon dioxide would move through the microscopic nooks and crannies.

It’s a key question for energy companies pinning their hopes on “carbon capture and sequestration” (CCS) as way to mitigate the high greenhouse gas emissions from burning fossil fuels. In practical terms, that means intercepting the CO2 and pumping it underground, essentially forever.

For the past five years, the Stanford team has collected beer can-size samples from rock formations all over North America. They then inject CO2 and water into the cores and take a CT scan, watching how it moves into the tiny pores spaces between individual grains of rock.

Authors say this new study offers the most detailed information yet about how the CO2 might behave underground in particular formations of rock. Benson says what surprised the team was how variable the rock was.

“Now we understand that certain portions of the rock have small pores and other portions have big pores,” Benson told me, after her presentation at this week’s meeting of the American Geophysical Union (#AGU11). “And the areas where you have small pores, it’s really difficult to put CO2 into it, so most of the CO2 ends up in the pore spaces that are the biggest.”

So would the carbon cache leak, releasing the CO2 back into the atmosphere? That was the burning question for Benson’s colleague, graduate student Lin Zuo, who studied the relative permeability of water and CO2. The answer is “No.” When the bubbles of gas come out of solution with the water, they plug up the rock formation because of their low permeability.

It’s a burning question outside the lab, as well. Without a successful CCS technology, there may be no way to reconcile the use of fossil fuels with their high emissions of greenhouse gases.

“Today we’re about 80% dependent on fossil fuels — a lot of natural gas, a lot of coal for electricity in particular,” says Benson, who directs Stanford’s Global Climate and Energy Project. “If we want to really quickly reduce those emissions, we need carbon sequestration as another option.”

The next question, says Benson, is, “We study rocks at a very small spacial scale — a cubic millimeter — but in reality these plumes are going to be very, very large — hundreds of square kilometers, so we need to take what we have learned and figure out how we can scale it up.”

Some say storing carbon underground as a way to curb greenhouse gas emissions is risky. The container has to last essentially forever, and what if an earthquake rips through the seal? But new research is showing that pumping CO2 underground could itself trigger earthquakes.

Stanford University geophysicist Mark Zoback looked at saline aquifers, one of the main types of geologic formations under assessment for carbon sequestration. He found that adding CO2 gas could increase the geologic pressure underground and set off a quake. Not a big one, mind you. Most likely you’d feel some shaking on the surface at a magnitude three or four. But underground the scenario would be a different story.

“At depth those earthquakes represent slip-on faults and if those earthquakes threaten the integrity of the geologic seal that’s keeping the CO2 in place, then they pose the hazard of inducing long-term leakage of the CO2 out of the repository,” said Zoback. “And of course that’s why it’s being injected in the first place, to keep it out of the atmosphere.”

The Earth’s crust is brittle because of shifting continental plates and just a bit more pressure can set off a quake in otherwise seismically safe areas. Never mind quake-prone California,” he said. “Even quiet places that have been eyeballed for carbon storage like the Midwest still have fault lines.”

To make a dent in global warming using carbon sequestration, about a billion tons of CO2 per year needs to be pumped underground by mid century – equivalent to the volume produced by burning oil and gas. Zoback figures that represents about 3,500 storage sites, or 75 new projects per year by 2050. He’s skeptical that all those sites can be found: “Are we going to invest the huge sums, we’re talking about many tens of billions of dollars only to find that when the earthquakes start occurring we’re going to have to stop the injection and find alternative strategies?”

Zoback presented his findings at the American Geophysical Union’s Fall Meeting in San Francisco.

Alison Hawkes is a freelance journalist in San Francisco and co-founder of Way Out West News.

Photo: Craig Miller

The dark underbelly of cap-and-trade was somewhat exposed in a four-hour hearing today before the Senate’s Select Committee on Climate Change and AB-32 Implementation. AB-32, of course, is shorthand for California’s Global Warming Solutions Act of 2006, which mandates a carbon trading program be in place by 2012.

Here’s my “highlights reel” from the panel of experts who testified, in order of appearance:

Mary Nichols, Chair, California Air Resources Board

- On carbon pricing: “There is no approach that does not involve administrative costs & headaches” but cap-and-trade “seems like a pretty good mix” of certainty provided by an enforced cap and market flexibility (versus an outright carbon tax of some sort).

- On California going “solo” with carbon trading (i.e. without the other states and provinces currently signed to the Western Carbon Initiative): The larger the territory, the more potential for “bad actors” but the greater the potential for meaningful savings & benefits to the economy.

Michael Wara, Stanford Law Professor

- On carbon offsets: “…difficult to administer;” to ensure real reductions, changes in behavior, has proven to be “a significant and ongoing challenge, in practice.”

- California appears to be “opting for prudent limits” on allowable offsets, at an anticipated 4%, versus more than 30% in the Waxman-Markey bill that has cleared the US House of Representatives.

- “Very few [offset] programs have been run without controversy.”

Ken Alex, California Attorney General’s Office

- On enforcement: “Every system has cheaters, especially where billions of dollars are involved.”

- Cap-and-trade provides “a permanent incentive for cheaters.” Unassailable data is essential for regulators.

- Regulators “must have sufficient authority” to assess meaningful penalties. Alex, who was involved in sorting out the state’s energy crisis of 2000-2001, recalled that “million-dollar penalties were irrelevant.”

Dallas Butraw, Economist, Resources for the Future

- Warned against a “phone book-sized” regulation.

- Cost of carbon emissions permits will be passed along to consumers but could be offset by tax breaks or a dividend system similar to what oil & gas companies pay to residents of Alaska.

David Harrison, Economist, NERA Economic Consulting

- On lessons from Europe: Despite a rocky start for the EU’s “pilot” program, the system for carbon trading in 27 countries has “evolved over time” to become “very successful.”

- The EU experience “really does show that cap & trade works. Emissions have been reduced.”

- There is “no silver bullet” for determining allocations; that in Europe has been a “messy” and “contentious” process.

- In spite of it all, the EU experience demonstrates that cap-and-trade is “not perfect but it really is better than the alternatives,” and provides a good laboratory for California.

The committee, chaired by Fran Pavley (D-L.A.), also heard from several business and environmental groups. At one point a speaker from the Natural Resources Defense Council (NRDC) argued briefly with a utility representative about whether electric rates are actually higher or lower in California, compared to the nation as a whole (apparent compromise: rates may be higher but average bills are lower).

Utilities complained that the system, as proposed, forces power companies to bear the brunt of the burden. Business interests warned that unbridled implementation of AB-32 “could add to an already alarming increase in job losses,” claimed that the state has no authority to hold carbon permit auctions under AB-32, and asked for initial permits to be given away to industry. Environmentalists asked for the opposite, urging that 100% of initial permits be auctioned off, i.e. that emitters be made to pay for them.

Numerous speakers expressed nervousness over validity of carbon offset programs. Regarding the various schemes for carbon storage in forests or soil, Assemblyman Jared Huffman (D-San Rafael) said “This one makes my head hurt.” There’ll be a lot of Excedrin passed around before this is through.

Carbon capture demo at the annual American Geophysical Union meeting. Photo: Molly Samuel

Almost lost amid the Copenhagen media clutter was last week’s meeting of the American Geophysical Union in San Francisco. So this week we’re playing a little catch-up. Lauren Sommer has the second of three posts on things that caught our attention at AGU.

Carbon capture technology has largely focused on the most convenient emissions sources–namely the stacks at large power plants. But as Columbia University’s Allen Wright showed at the American Geophysical Union conference in San Francisco last week, there are other ways to do it.

Wright and colleagues demonstrated their “air capture” technology, where carbon dioxide is absorbed straight from the air by something that looks a lot like a gadget for cleaning Venetian blinds. It’s a special plastic material with a sponge-like consistency. Once the carbon is absorbed, the material is exposed to water or water vapor which causes the carbon to be released. It can then be captured. Wright says it captures CO2 three to five times better than a leaf in full sunlight.

On a large scale, this technology might be built into “artificial trees” that could be stationed anywhere around the globe. The prototype, designed by Wright’s Global Research Technologies, doesn’t look much like a tree. It’s a shipping container with a circular, rotating basket on top where the air capture units are exposed to the air. After one rotation, the baskets would be brought “downstairs” where the carbon is captured. From there, the carbon could be geologically sequestered or even used to make beverages bubbly.

Of course, the main criticism of this approach is efficiency. Carbon dioxide is only about 0.04% of the atmosphere, which is why more concentrated sources like power plant stacks get more attention. Wright says capturing carbon from power generation will be important, “but capture at the stack isn’t enough. It won’t do what has to be done. Air capture has the advantage of being able to deal with emissions from anywhere on the planet from any source.”

Cars are one of the sources he’s talking about. Their prototype unit is designed to capture a ton of carbon a day, which would neutralize the emissions from about 20 cars. They hope to get the cost of each carbon-capturing unit down to the price of car, so the cost of reducing a ton of carbon could one day be similar to other technologies.

Still, to make an impact on global emissions, millions of these units would need to dot the landscape. And just as with renewable energy, NIMBY issues are a potential roadblock. But as is a common refrain these days, Wright says if we’re serious about cutting emissions, we’ll need every technology that shows promise.

The idea seems simple enough: In order to get energy, we burn carbon. In most cases, that carbon comes out of the ground in the form of natural gas or coal. So instead of releasing the resulting carbon dioxide emissions into the atmosphere, why not put it back into the ground?

Of course, carbon capture and storage/sequestration (CCS) is much more complicated than that. Nonetheless it’s a strategy that’s being pursued aggressively by both international leaders and US Energy Secretary Steven Chu, who would like to see it deployed in ten years.

There are obstacles on both the “capture” and “storage” side of the equation. In terms of technology, however, “storage” is much further along, thanks to the oil and gas industry, which is already using CO2 in oil recovery. Injecting compressed CO2 into oil fields forces more oil to the surface in a process known as enhanced oil recovery. As many in the industry will remind you, they have three decades of experience doing this.

Keeping it underground is another matter. In the western US, the West Coast Regional Carbon Sequestration Partnership (WestCarb) is setting up a number of pilot projects to study how CO2 can be safely stored underground. As Technical Director Larry Myer explained to me, one of the primary goals is to simply work out the regulatory, siting, and liability issues.

As with any waste issue, choosing the site is the most important–and often most difficult–issue. California’s Central Valley has plenty of underground saline aquifers and depleted oil and gas fields that could hold CO2. But the trick is finding a site where the geology can securely store it and where there’s little risk of groundwater contamination. On the plus side, scientists know that CO2 is slowly immobilized underground, which lessens the risk over time. But how long that takes is still under study.

As for the “capture” issue, there are three ways to separate CO2 from power plant emissions.

• In today’s Climate Watch story, I describe Oxyfuel technology, in which natural gas is burned in pure oxygen. Since the outputs are steam and carbon dioxide, the CO2 can be easily siphoned off. But that requires building new power plants from scratch.
• The second option seeks to deal with the carbon dioxide before the fuel is burned; a “pre-combustion” approach. Or for all you wonks out there: Integrated Gasification Combined Cycle (IGCC). The downside to this process is that it requires gobs of energy, which makes it expensive.
• Finally, there’s the “post-combustion” approach. That’s where the CO2 is “scrubbed” from flue gas after the fuel is burned. Existing plants can be retrofitted with this technology, but it also comes with large energy penalty, just like IGCC.

A price on carbon, through either a cap-and-trade system or carbon tax, would change the economic case for CCS, but there are a lot of strikes against the technology. So why pursue it?

The argument goes like this: In order to achieve steep emissions cuts–say an 80% reduction worldwide by 2050–it may be an important tool (or stabilization wedge).  The world will continue to use fossil fuels in the near term and despite the enormous growth of renewable energy, it’s still a drop in the bucket. That’s why many believe that CCS is a crutch the world needs to wean ourselves from fossil fuels.

Of course, when it comes to reducing carbon emissions, capture is only half the battle. The carbon snared from these plants is only temporarily stored – it gets released eventually–like when someone pops the top of the soda can.  It’s more like carbon recycling. The greater hurdle is in “sequestering” part of it.  In order to make a lasting difference in cutting emissions, that carbon has to be stored permanently.

President Obama has signaled that developing carbon sequestration technology is a key part of his energy plan, and is handing out billions in stimulus dollars.  But the U.S. is already behind the curve.  While there are several ways to store carbon, the main focus has been on storing carbon underground in geologic formations. There are several power plants in Europe that are already capturing and sequestering carbon emissions underground.  The Bush Administration backed off its first attempt at carbon capture and sequestration (CCS), the FutureGen project, in 2008 after the costs became too high. The name of game now is to simply get a demonstration plant working. Anywhere.

Here in California, CCS is an option, thanks to the underground geologic formations throughout the Central Valley that could be ideal sites. A western consortium known as WESTCARB is leading the charge with backing from the California Energy Commission and the Department of Energy.  They’ve announced a pilot project in Bakersfield where carbon will be captured from a 50-megawatt power plant. But construction is described as still “months away.”

As with any new technology, cost is the make-or-break issue.  Capturing and stashing carbon is prohibitively expensive–at least until there’s a price on carbon or the technology improves. This week, Energy Secretary Steven Chu said he doesn’t expect to see cost-effective technology for at least eight years. And he raised another point. “Even if the United States or Europe turns its back on coal, India and China will not,” Chu said.  At last fall’s climate summit in Los Angeles, members of the Chinese delegation told Climate Watch that they were looking to the U.S. to provide key technology. But as Anthony Kuhn reported, the Chinese went to Australia to get technical advice.

It’s commonly forecast that coal will remain a central power source in the U.S. for decades to come. But as critics of carbon sequestration have stated, it’s really a question of whether cost-effective technology will arrive in time to slow down climate change.

Lauren Sommer is an associate producer with Quest at KQED, and a self-described “carbon geek.” Her story on plans for a “smart” electrical grid is Monday’s Quest Radio feature.