Fewer acronyms would make more sense, failing which, a glossary. On Friday, August 23, 2013 2:05:20 PM UTC-4, Greg Rau wrote: > > Article below. The usual suspects and viewpoints, e.g. : > > "Pulling vexing carbon emissions straight from the sky might become an > important way to keep climate change in check. As pilot projects move > forward, the prospect of capturing carbon dioxide from the air is growing > increasingly plausible, though it may be some time before the technology, > the demand and the costs align to make a dent in global emissions." > > To review, pulling those pesky carbon emissions straight from the sky > already > annually consumes 55% of our emissions for free, and the absolute quantity > of this "DAC" is (lucky for us) increasing: > http://www.sciencemag.org/content/early/2013/08/07/science.1239207.full > If one is interested in further "denting" global emissions, perhaps the > first thing to do is to figure out how to additionally > accelerate/enhance/modify/engineer these existing, highly successful > systems, rather than ignoring nature and designing a new air capture > process from the ground up. > > "....for carbon capture systems [DAC], the main energy sink isn't so much > in collecting CO2 in the first place, but in regenerating the absorber and > making a pure stream of the gas." > > Exactly. This is why nature's existing, very successful CRD assiduously > avoids this step and why our attempts at further "denting" air CO2 should > also. On the other hand if CO2 EOR is your end game, then you are obviously > stuck with making conc CO2 while also increasing atmospheric CO2: typically > in EOR CO2 in<< oil CO2 out. How such schemes get mentioned in the context > of saving the planet is something I find breathtaking. > > Speaking of actually saving the planet, if you haven't already done so, > there's still time to vote for The Planet Physician's air capture (and so > much more) concept here: > > http://climatecolab.org/web/guest/plans/-/plans/contestId/20/planId/1303630 > and/or vote for this point source CO2 mitigation idea: > > > http://climatecolab.org/web/guest/plans/-/plans/contestId/10/planId/1304003 > > Your humble messenger, > Greg > > > CARBON CAPTURE: > Air capture needed as a tool to fight climate change, scientists say > > Umair Irfan, E&E reporter > Published: Friday, August 23, 2013 > > Pulling vexing carbon emissions straight from the sky might become an > important way to keep climate change in check. As pilot projects move > forward, the prospect of capturing carbon dioxide from the air is growing > increasingly plausible, though it may be some time before the technology, > the demand and the costs align to make a dent in global emissions. > > Earlier this year, instruments showed atmospheric carbon dioxide > concentrations rising above 400 parts per million for the first time in > 800,000 years > (*ClimateWire*<http://www.eenews.net/climatewire/stories/1059979974/>, > April 24). > > Energy consumption, and consequently carbon emissions, is poised to grow > further even as cars, homes and aircraft become more efficient. Fossil > fuels will continue to be the major energy source in the coming century as > countries like China harness this energy to drive economic development. > > As a result, some researchers argue that direct air capture is a > necessary, though not sufficient, component of any climate change > mitigation strategy. > > "Our view is that air capture is a pathway that could be quite important," > said David Keith, president of Carbon Engineering, a firm developing > industrial air capture systems. He explained that controlling emissions at > the source makes sense for large facilities like power plants and factories > but scrubbing carbon dioxide from tailpipes or jet exhaust is too expensive. > > The transportation sector accounts for 28 percent of greenhouse gas > emissions in the United States, according to U.S. EPA, so there is still a > critical need for a way to reduce the overall carbon dioxide produced from > mobile sources. > Trapping CO2 in a liquid > > Carbon Engineering is addressing this with a box fan-like air contactor > that uses a liquid to sop up carbon dioxide from the air. The liquid, now > enriched, circulates to a regeneration facility where it releases the > carbon in a pure stream under high temperature. > > This pure carbon stream is very useful, Keith observed. Carbon dioxide is > a raw material for certain industrial processes, drillers use it to squeeze > out more oil and gas from depleted wells and it serves as a building block > for liquid fuels. > > "We are trying to reduce the risk by using technologies that are proven," > he said. The company is designing a large pilot plant that will capture 1 > kiloton of carbon dioxide annually, due to come online next year in Alberta. > > Putting carbon dioxide to work is an important step toward making direct > capture economically feasible as well as environmentally sustainable. > Unlike a stream from a carbon capture system attached to a coal-fired > generator, an air capture system recirculates carbon that is already in the > atmosphere. > > Using this carbon instead of the stuff from the ground to make gasoline or > jet fuel means it offsets humanity's carbon output so that there is no net > change in CO2 concentrations in the atmosphere, provided the energy driving > the process comes from a carbon-neutral generator. > > "When you drive your car and emit some carbon and I capture that carbon > and use it to make fuel for the car, then effectively I've created a closed > loop," said Tim Fox, head of the Energy and Environment Division at the > Institution of Mechanical Engineers speaking last month at the U.S. Energy > Association in Washington, D.C. > > Because carbon dioxide is fungible once it enters the atmosphere, Fox said > it doesn't matter where developers build an air capture system. It doesn't > have to be near a specific carbon source and can use cheap, marginal land, > thereby reducing overhead. > > Fox suggested that engineers could site air capture systems near stranded > renewable energy sources, like sunny islands or windy, desolate cliffs. > Would zero-emission vehicles cost less? > > However, others are skeptical. "Capture from the air is very expensive. > Those ideas just make it more expensive," said Howard Herzog, senior > research engineer at the Massachusetts Institute of Technology's Energy > Initiative. > > Herzog co-authored a study in 2011 that concluded direct air capture uses > too much energy and costs too much to be an effective strategy to fight > climate change > (*ClimateWire*<http://www.eenews.net/climatewire/stories/1059957553/>, > Dec. 13, 2011). He said gradually switching to zero-emission vehicles would > likely be cheaper and more effective at reducing emissions than offsetting > tailpipe CO2 with air capture. > > In order for air capture to make a difference in the climate, the > technology and economics would have to change radically. "The first thing > that's essential is you have to totally decarbonize your power system," > Herzog said, referring to the energy needed to feed direct air capture > devices. "The second thing, the electricity, the power you buy from this > system, must become inexpensive. If that's the case, then it starts > becoming more in the realm of possibility." > > Still, researchers are pressing on and looking for better ways to collect > carbon dioxide from the air. "I think people are too pessimistic," said > Klaus Lackner, director of the Lenfest Center for Sustainable Energy at > Columbia University. "If you look at the first-of-a-kind price of a new > technology, it's not terribly informative." > > Air capture systems would follow cost trajectories similar to those of > wind and solar energy as the devices get better and companies build more of > them, Lackner said. He noted that for carbon capture systems, the main > energy sink isn't so much in collecting CO2 in the first place, but in > regenerating the absorber and making a pure stream of the gas. > 'Cleaning up' after ourselves > > Scientists are therefore concentrating on improving the mechanisms used to > snag and release carbon dioxide. Lackner developed a mechanism that > passively collects CO2 on a membrane and releases it when wet, thereby > avoiding energy-intensive fans and high temperatures. Kilimanjaro Energy is > currently working to commercialize this system. > > The process, however, still requires more energy than capturing emissions > at the source. "The bottom line is, I pay a penalty, but it's a relatively > small penalty, and that penalty is worth it for going after those emissions > no one else is," he said. > > In addition, air capture creates leverage that could aid international > climate negotiations. "You could tell, for example, the coal producers or > the coal consumers, 'You should clean up your own CO2, but if you don't, we > will do it on your behalf and we will charge you for it,'" he said. > > One criticism is that directly trying to change the atmosphere falls > within the shadow of geoengineering, so air capture deserves extra > scrutiny. Another issue is that some environmental groups, like Greenpeace, > view carbon capture systems as a moral hazard and a way to enable > complacency. With a way to pull carbon out of the air, people will not > limit their emissions and will do less to address climate change, the > argument goes. > > Lackner said the motivation here is actually the opposite: Because the > warming planet is such a threat and current systems aren't doing enough to > solve the problem, researchers need to pursue every option and don't have > the luxury of leaving direct air capture off the table. > > "It's cleaning up after yourself, and it has very little to do with > geoengineering," he said. "I view this as CO2 emissions control and closing > the anthropogenic carbon cycle." >
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