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Geoengineering. Can we fix things while doing as we do now? 1. Dispose of CO 2 (CCS or to the ocean depths) 2. Change the earth’s albedo. Sources:. R. Socolow , Scientific American, July 2005 Special section, Science 25 Sept. 2009. CCS=Carbon Capture and Sequestration.
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Geoengineering Can we fix things while doing as we do now? 1. Dispose of CO2 (CCS or to the ocean depths) 2. Change the earth’s albedo.
Sources: R. Socolow, Scientific American, July 2005 Special section, Science 25 Sept. 2009
CCS=Carbon Capture and Sequestration Capture CO2 into some chemical from the exhaust stream of power plants Release this CO2 into a pure stream Compress or liquify it Pump it deep into permeable or porous deposits, under impermeable cap rock Or, into deep brines
FutureGen Demonstration ‘clean coal’ plant, high efficiency, CCS, making hydrogen. Using IGCC Mattoon IL, 2003, 275MWe, cost $1.8B 75% federal, 25% private CCS 1 million tons of CO2/year for four years Cancelled 2008, perhaps back to life
numbers • FutureGen to capture one million tons/year • US burns 109 tons of coal per year • 109 tons of coal x ½ carbon x 44/12 = 1.8 billion tons of CO2/year • FutureGen 106/1.8x109 = 0.05%
IGCC • Integrated Gasification Combined Cycle • Coal to gas (C+H2OCO + H2) • Burn the gas in turbinespower • Hot turbine exhaust steampower • Efficiency ~ 60%! • Use separated oxygen, not air, exhaust stream nearly all CO2
Then what? Lake Nyos, Cameroon, 1986 Naturally sequestered volcanic CO2 burst out, killing 1700 people, all animals within 25 km radius
Drawbacks to CCS Only about 15% CO2 The technology, cost to capture. How to deal with small sources. Storage dumps—forever! Liability The scale of the problem
(8) The world burns about 8 billion tons • of coal each year, about half of which • on average is carbon, making 14.7 billion • tons of CO2, as in your recent homework, • equal to 13.3 billion metric tonnes. The • density of CO2 in its densest form as a • liquid is 1100 kg/m3. If we were to bury • the CO2 just from our coal burning, how • many cubic meters of such liquid would • we have to bury? Compare this volume • to global petroleum production of 4.2 billion • metric tonnes per year, at an average • density of 900 kg/m3. What are you going • to tell a policy maker considering CCS • (Carbon Capture and Sequestration)? • I will tell you also that such liquid requires • a pressure at least 5.1 times that of the • normal atmosphere, and at that pressure,
Iron fertilization of the oceans Iron in the water is the limit to open ocean life. Add iron, plankton bloom, die, sink. Visible from orbit.
Increase atmospheric albedo, reflect sunlight Natural experiment, Mt. Pinatubo SO2sulfuric acid, nucleates water into clouds
EYJAFJALLAJOKULL Source of all that heat energy? Internal radioactivity, uranium, thorium 40K Akin to meltdown of TMI core. Cooling or melting?
Space mirrors Change the solar constant
Cloud yachts • Spray mist into clouds
Drawbacks-albedo Must keep the albedo high Local influences-rain
Read for April 23 New York Times Magazine April 11 2010 Building a Green Economy Paul Krugman