The Future of Coal Carbon Capture and Storage

The Future of Coal: Carbon Capture and Storage Dmitri Malinin Fall 2006 CBE 555 Presentation Overview  Plan to Keep Carbon in Check Background  Overview of Plan  How Carbon Capture and Storage Fits In  Action Plan  Current Implementation of CCS  CCS Technology  Summary  Background  Ominous harbingers of global warming  Driving governments and companies to evaluate fossil fuel use Dig up and pump out ~7 billion tons of carbon/yr  Currently the fossil fuel industries:   Society burns nearly all of it Background   Danger boundary exists at doubling preIndustrial Revolution carbon conc. Avoiding danger zone would reduce chances of triggering, major irreversible climate changes  E.g. Greenland ice cap disappearance Future Scenarios  Future Separated into two 50-year scenarios: 1) 2) Emissions rate continues to grow at pace of last 30 years for the next 50 years, reaching 14 billion tons carbon/yr in 2056 Emissions are frozen at the present rates of 7 billion tons/yr for the next 50 years, then cut in half for the subsequent 50 years “Stabilization Triangle”  The stabilization triangle represents difference between two emissions scenarios  Represents total emissions cuts that climate-friendly technologies must achieve in the coming 50 years Each a reduction of 25 billion tons of carbon over 50 years  Triangle divided into 7 wedges  Wedge Framework  Allowed to count as wedges only differences in two 2056 worlds as result of deliberate carbon policy  Belief that cars will be more efficient regardless of emission policy does not count  Allowed to only count strategies involving currently commercialized technologies Why Carbon Capture and Storage?  Coal has become more competitive source of power Energy security concerns  Increase in the cost of oil and gas   Carbon plant burns twice the carbon per unit of electricity as natural gas plant Why Carbon Capture and Storage?  Absence of concern World’s coal utilities could build few thousand conventional coal plants in next 50 years  700 of these plants emit one carbon wedge  Projection that 6 out of 14 billion tons of carbon emissions will come from power generation, mostly from coal Why Carbon Capture and Storage?  New coal plants should be built with carbon capture technology in place  More expensive to revamp existing facilities  Oil prices driving down the cost of transition Captured CO2 can be sold to oil companies  The higher price of oil, the more valuable the CO2  Action Plan  To routinely use carbon capture and storage Requires institutions that reliably communicate a price for the present and future  Price estimate of ~$100-200/ton of carbon  Price range makes it cheaper for owners of coal plants to capture and store CO2  Action Plan Governments need to stimulate commercialization of low-carbon technologies to increase number of competitive options in future  Policies to prevent construction of longlived facilities that are mismatched to future policy   Utilities need to be encourage to invest in carbon capture and storage, because of retrofit costs to older technology Action Plan  To keep atmospheric CO2 concentration levels below risk level requires  Power industry start commercial-scale CCS within few years and expand rapidly thereafter  In combination with other “wedge” captures Geologic Storage Strategy  Procedure for CCS involve Separation of CO2 created by generation of energy from coal  Transport to sites where it can be stored underground in porous media   Depleted oil or gas fields or saline formations (permeable geologic strata filled with salty water) Geologic Storage Strategy  Carbon capture technologies have been deployed world-wide Manufacture of chemicals  Purification of natural gas contaminated with “sour gas”   Industry has significant experience with CCS in: Natural gas purification in Canada  CO2 injections to boost crude output  Main Concerns Issues   Sudden Escape  Gradual Escape  Sudden release of CO2 could be lethal Negates the purpose of putting it in the ground  2005 IPCC report estimated that in appropriately selected and managed reservoirs, fraction retained Likely to exceed 99% over 100 years  Likely to exceed 99% over 1000 years  Technology Choices-Conventional  Conventional pulverized-coal steam cycle Burns coal in boiler  Heat generated in combustion generates steam  Steam turns turbine  Electricity from mech. energy with generator  Technology Choices-Conventional  Modern plants  Particulates and oxides of sulfur and nitrogen removed from flue gas  Disadvantage of CCS Flue gases contains substantial amounts of nitrogen  CO2 recovered at low temp. and press. from large volumes of gas  Processes energy-intensive and expensive  Technology Choices-IGCC Integrated gasification combined cycle (IGCC) more cost and energy effective than conventional pulverized-coal steam cycle  Gasification systems recover CO2 from a gaseous stream at high concentration and pressure  Pre-combustion removal of pollutants   Realize very-low emissions at reduced cost and energy penalty Technology Choices Captured CO2 transported by pipeline to suitable geologic storage sites and subsequent subterranean storage  Pressure produced during capture used to transport  Costs  Cost of CCS depend on Type of power plant  Distance to storage site  Properties of the storage reservoir  Availability of opportunities for selling capture CO2   Cost of CCS will dampen demand for electricity  Energy efficient and renewable energy products more desirable to consumers Summary      Need to implement initiative for holding carbon emission levels constant for next 50 years Coal is abundant source of energy Need to control emissions from coal-powered plants through CCS IGCC plant is most feasible choice for CCS Cost of CCS will create drivers for energy efficiency References “A Plant to Keep Carbon in Check”, Socolow & Pacala, Scientific American, September 2006.  “Can we bury Global Warming?”, Socolow, Scientific American, July 2005.  “What to do about Coal”, Hawkins, Lashof, & Williams, Scientific American, September 2006. 