2. Carbon Sequestration Scott Tovsen 15 Oct 2012

3. Overview Motivation Sequestration Processes Biological Physical Chemical Emissions & Costs Perspective Conclusion

4. Carbon Sequestration* – capture and long term storage of atmospheric CO2 * also known as carbon capture and storage (CCS),

5. Closing the carbon cycle

6. CO2 Status Each year human activities produce: 29,000 megatonnes=29,000 million tons of CO2 [1] *does not include natural sources/sinks which are relatively balanced and dwarfed by human activity (300 million tons for all volcanoes averaged annually) 551 Billion tons of CO2 since start of industrial rev Successful sequestration must be able to capture at least that amount to continue life as normal [1] U.S. Geological Survey, "Volcanic Gases and Their Effects", volcanoes.usgs.govVolcanic Gases and Their Effectsvolcanoes.usgs.gov

7. Biological Processes Peat Bogs Reforestation Agriculture

8. Peat Bog

9. Reforestation

10. Agriculture

11. Physical Processes Bioenergy Burial Biochar Ocean Storage Subterranean Injection

12. Bioenergy Carbon Flow “Building a sustainable biofuel future” Prof. Chris Kucharik UW – Madison Department of Agronomy

13. Burial Mimic fossil fuel production Same carbon balance issues as with bioenergy Long timeline

14. Biochar Increases soil fertility Up to 50% of carbon captured during pyrolysis Can be buried or tilled into fields

15. Ocean Storage  Liquid carbon pumped at depth to form lakes  Now illegal due to international regulations on marine dumping  Oceans already store ~50% of CO2 released to atmosphere

16. Subterranean Injection Increased oil recovery Offset any CO2 reduction Depleted reservoirs likely to maintain 99% over 1000 years [Global CCS Institute] Lake Nyos, Cameroon 1986 1700 people asphyxiated from to CO2 leak due to volcano

17. Chemical Processes Mineral Storage (weathering) Chemical Scrubbers

18. Mineral Storage (weathering)  Oxides:  CaO + CO 2 → CaCO 3  MgO + CO 2 → MgCO 3  Silicates:  Mg 2 SiO 4 + 2CO 2 = 2MgCO 3 + SiO 2  Mg 3 Si 2 O 5 (OH) 4 + 3CO 2 = 3MgCO 3 + 2SiO 2 + 2H 2 O  Exothermic reactions & occur naturally on geologic time periods

19. Chemical Scrubbers  MANY techniques  Potassium carbonate  $150 per ton of carbon captured  Adds 2.5 - 4 cents/kWh to your electric bill [US Department of Energy]  84% increase in electricity costs from coal power  Removes 80-90% of CO2

20. Emissions & Costs

21. Sequestration Costs  Bay Area, CA:  4.4 cents/ ton of CO2  Businesses  Montgomery Co, Maryland  $5 /ton of CO2  Single power plant  Carbon Scrubbers:  $150 per ton of carbon captured sequestration costs >>> carbon tax

22. Perspective Carbon tax MUCH less than cost to sequester carbon Paying for externalities would equalize the playing field for alternate energy High carbon tax would spur innovation in carbon sequestration technologies and reduce costs

23. Conclusion Motivation Sequestration Processes Biological Physical Chemical Emissions & Costs Perspective

24. Discussion & Questions THANK YOU