Friday, June 20, 2008

Test Shows Capture of 95% of CO2 at Coal Plants - So What?

source: http://www.ecogeek.org/content/view/1781/81/



Cicero has released a report touting how a new experimental carbon sequestration and disposition system can drastically lower CO2 levels and significantly improve our climate change prognosis. The report says that if all new coal power stations could be built based on this technology, we'd basically be able to declare "Mission Accomplished." This is kind of a "Duh" statement in that of course if we got rid of the CO2 issue at one of the biggest sources of the gas, then green house gas levels would plummet. With a little digging, the reality of this statement turns out to be just what it seems at first glance - too good to be true and too simple to be realistic.

Carbon sequestration is on everyone's minds. But while effective capture methods have been developed, the question remains: what do we do with all that CO2 we've got bottled up?

The Ultra Low Emissions technology is, in fact, real. Norwegian clean energy specialist company Sargas has created a system that captures, cleans, and stores carbon emissions from coal plants. And they have the ideas on how to get rid of it, too. They've successfully tested the carbon capture technology on a small scale at a coal plant Värtaverket in Stockholm, and proven that the system captures 95% of CO2. In fact, all the major goals of the test were met, including the high level of capture, ease of use, how clean they were able to get the gas and make it "turbine-ready" and the reduction of NH3, SO2 and HCI to below-detection levels.

The experiment proves that the method and technology for capture and cleansing is now here and can easily be scaled up for commercial purposes. But what it also proves is...well, not much. Their technology can only be utilized on new coal plants or retrofitted on existing coal plants that utilize Pressurised Fluidised Bed Combustion (PFBC) technology, because their system works under pressure. While they note that the major polluters include the US, China and India, retrofitting can occur only at PFBC plants located in Sweden, Japan and Germany. Most plants produce emissions at atmospheric pressure. So the technology doesn't exactly go far for cleaning up coal.

"Through the project we have obtained scientific proof that our technology works," says Henrik Fleischer, Chief Executive Officer of Sargas. "It means that we can now offer coal power station solutions with CO2 capture to the market on commercial terms. Our solution is based on standard industrial components - boiler and cleansing plant. We have managed to make them work together in a new way, using a technological solution we have developed and patented worldwide. Because of this we have no scaling problems as the main components are in daily use independently all over the world. Coal is a cheap fuel for power production and will have a central role as an energy carrier for the foreseeable future in large parts of the world. Our technology means that the world can continue to utilize coal in the future as well, but without the climate suffering." While it paints a pretty picture of skipping through green fields, pockets full of gadgets that cost pennies to charge, it also sounds a little broad and idealistic.

The company isn't a head-in-the-clouds company, though. They've worked with some serious partners, including the Swedish Royal Institute of Technology (KTH), Massachusetts Institute of Technology (MIT) and Siemens. Additionally, the Institute for Energy Technology (IFE) at Kjeller assisted with the control of methods and results. But while Cicero's report saying how amazing this technology could be is accurate when using their assumptions, the assumptions are off base. The assumptions include all new coal plants built after 2015 utilize the technology, and that all CO2 can be safely stored in geological formations - a MAJOR issue not yet resolved, and one so big, it makes carbon capture seem a little pointless.

CO2 needs to be stored deep in geological formations - deep, as in several thousand feet deep, in the low-density strata that lies under the impermeable "caprock" strata. Supposedly it can also be injected into abandoned gas and oil wells or deep saline aquifers, but that remains sketchy. And in order to be injected into this nearly impossible to reach depth in a way that it doesn't leak right back out, the CO2 has to be compressed to about 100 atmospheres before injection.

Okay, say we deal with all that and can get it underground. We still have to deal with the sheer volume of emissions we put out at coal plants. The largest carbon sequestration pilot project so far can only handle about 10,000 tons each day, whereas the average coal power plant spits out 24,000 tons each day. That's ONE plant. The scaled down version of Sargas's technology only processed 130 lbs of exhaust gasses and hour, and if assumed it worked round the clock, that's only just over 1.5 tons a day...and that's being processed, but not disposed of. Beyond even our ability to inject carbon into geological formations, we may not even have the room inside the earth to hold all the carbon we spit out.

I think the report and the experiment actually prove two things. First, carbon capture and cleansing is possible and can be utilized in the future. But second, either figure out a clean use for all that CO2 - like feeding it to algae or turning it into wallboard - or coal plants need to be phased out.

Via Cicero, Sargas, Reuters UK, Norway Post, WorldChanging

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