Clean Coal

1. Clean Coal Oxymoron or Key to Energy Independence? Michelle Chesebro mjchesebro@sbcglobal.net

2. Current Coal Usage • 50% of the energy in the U.S. is generated from coal • More than 500 coal-fired power plants in U.S. with average age of 35 years • U.S. supplies of coal projected to last from 164 -250 years

3. Economics and Security of Supply • Coal is plentiful and cheap • Coal is found in abundance in countries with stable governments • United States, India, China • MIT concluded that coal will continue to be used to meet the world’s energy needs in significant quantities.

4. Greenhouse Gases • Among fossil fuels, coal is the most carbon-intensive so electricity generated by coal produces high CO2 emissions • U.S. coal-burning power plants contribute 1.5 billion tons per year of CO2 • Globally, coal is responsible for 40% of CO2 emissions

6. China’s Contribution to Greenhouse Gases from CO2 • International Energy Agency now predicts China will surpass the U.S. in CO2 emissions by 2009, 10 years earlier than previous projections • China uses more coal than the U.S., the E.U. and Japan combined • China is bringing new coal-fired power plants online almost every week

8. Proposed Solution • Carbon Capture & Sequestration (CCS) – can reduce CO2 emissions significantly while using coal to meet energy needs • Components:

9. Initial Step: Coal Gasification • Coal put in gasifier with oxygen and steam where heat and pressure are used to form a synthetic gas, known as “syngas” • CO2 can then be captured • Before combustion (IGCC) • After combustion (Pulverized Coal plants)

10. Product: Syngas • Composition – Carbon Monoxide and Hydrogen • Potential Uses • Power Generation (IGCC) • Fertilizers & Methanol • Natural Gas • Gasoline & Diesel Fuels (Fischer-Tropsch)

11. Post-Combustion Capture • Used in conventional pulverized coal-fired power (PC) plants that produce flue gases • CO2 separated out from flue gas • 80-95% captured (but low concentrations to begin with in flue gas)

12. Post-Combustion Process • Flue gas is passed through an absorber where a solvent removes most of the CO2 • CO2-containing solvent goes to stripper and is heated to release the CO2 • New process being used by American Electric Power: chilled ammonia used as solvent – can process larger amounts of CO2, but requires less energy

13. Post Combustion

14. Pre-Combustion Capture • Integrated Gasification Combined-Cycle (IGCC) technology • Used in new power plants and well suited for high grade bituminous coal • 90% of CO2 removed

16. IGCC Process • Coal gasification to produce syngas • Syngas cooled and cleaned to remove particulates and other emissions • Electricity generation • Syngas then combusted with air or oxygen to drive gas turbine • Exhaust gases are heat exchanged with water/steam to drive steam turbine • By introducing steam between cooler and gas clean-up, CO converted to CO2 which can be captured and stored before combustion

17. IGCC Process • Coal burned to produce syngas • Syngas burned in combustor • Hot gas drives gas turbines • Cooling gas heats water • Steam drives steam turbines

18. Competing Technologies • Because of the differences in coal type, a wide range of technologies will need to be deployed. We should not jump on the IGCC bandwagon too quickly for research & development $$$, but continue to fund a variety of options • Clear preference for IGCC or SCPC (Super Critical Pulverized Coal) cannot be justified at this time

19. Comparison of IGCC and SCPC • Reasons to prefer IGCC • Potential tightening of air quality standards for other pollutants reduced by IGCC, such as SO2, NOx and mercury • Likelihood of a future carbon charge • Possible federal or state financial assistance for IGCC • Reasons to prefer SCPC • Near-term opportunity for higher efficiency • Capability to use lower cost coals • Ability to cycle the power plant more readily in response to grid conditions • Confidence in reaching capacity factor/efficiency performance goals

20. Retrofitting Costs • Major technical modifications required regardless of which technology is used • Based on today’s engineering estimates, cost of retrofitting for IGCC appears to be cheaper than retrofitting for SCPC • Variables • Timing and size of carbon charge • Difference in retrofit cost • Very possible that old plants will just have to be bulldozed because retrofitting will prove to be cost-prohibitive

21. Another Option – UCG • Underground Coal Gasification • Addresses other environmental concerns associated with coal mining

22. Other Technologies • Oxygen fired pulverized coal combustion (more promising for lower quality coals) • Burning coal in oxygen-rich atmosphere to produce a pure stream of CO2 • Chemical looping combustion • Continually looping two stage reaction process that provides two waste streams from coal combustion • The first contains carbon dioxide and water, and the CO2 can be compressed for storage

23. Transport of Captured CO2 • Compressed to supercritical fluid • Dense as liquid • Gas-like viscosity • Transported through pipelines • Or further cooled and transported in marine tankers like LNG

24. Sequestration

25. Storage of Captured CO2 • Deep geologic formations such as saline aquifers • Depleted oil and natural gas fields • Ocean • Dissolving CO2 deeper than ½ mile • Depositing liquefied CO2 on sea floor 2 miles down

26. Carbon Options • CO2 pumped into disused coal fields displaces methane which can be used as fuel • CO2 can be pumped into and stored safely in saline aquifers • CO2 pumped into oil fields helps maintain pressure, making extraction easier

27. Storage Concerns • Leakage presents an immediate hazard to humans and ecosystems (CO2 is an asphyxiant) • Possibilities • Blow-out at injection well • Slow leak through faulty well or ground fractures • Even slow leaks negate the benefit of burying the CO2 in the first place

28. Regulatory Framework for Storage • Must include: • Site selection • Injection and surveillance • Eventual transfer of liability to the government • The goal of energy independence cannot be allowed to trump global warming concerns. Even if a regulatory framework is developed for the U.S., who will be the global carbon police?

29. Status of CCS Projects • Current IGCC Projects – used primarily for enhanced oil & gas recovery, not CO2 storage • Sleipner in Norway • Weyburn in Canada • In Salah in Algeria • Need large-scale demonstration before this can be considered a viable proposal • Large-scale electricity generation – proposed projects: • FutureGen in the U.S. • ZeroGen in Australia • A number of proposals in Europe and Canada

30. Price of Coal • Coal is plentiful and currently cheap because the health and environmental costs are borne by the public, not the industry • But price will increase • Charge for CO2 emissions to account for health and environmental costs • Deploying carbon capture and storage will increase price of coal-fired power by at least 50%, with some estimating twice that amount

31. Grandfathering Loophole • Utilities may be tempted to invest in new power plants without capture in the hope that these plants will be grandfathered in • Expectation of free CO2 allowances under future carbon emissions regulations • Benefit when electricity prices increase as a result of a carbon control regime • Congress needs to close the loophole

32. Coal to Liquid • The bigger hurdle for energy independence is finding a replacement for gasoline. Other countries have used a process for turning coal into gasoline (Nazi Germany and the apartheid government of South Africa). • Coal  Gasifier  Syngas • Fischer-Tropsch Process • Syngas  Reactor  Hydrocarbons • Hydrocarbons cooled = liquid fuel • Concern – Coal to Liquid (CTL) development has no near-term plan to capture any of the CO2 it produces. Until it does, using the label “clean coal” is inaccurate.

33. Liquid Fuel from Coal • Second approach – direct coal liquefaction  coal is pulverized and mixed with oil and hydrogen in a pressurized environment

34. CTL • CTL with carbon capture • Will be incredibly expensive and will require government subsidies • If 85% of the CO2 is captured, the liquid fuel that is produced will have the same emissions as a gallon of regular diesel • CTL without carbon capture • May be economically viable without government subsidies • Will be a disaster in terms of global warming

35. Concerns • Technological issues for both capture and sequestration are not trivial and we are still at least five to ten years away • Any sequestration method still has the potential for leaks • Impact to human health – high concentrations of CO2 causes loss of consciousness • CO2 makes water in aquifers acidic enough to dissolve certain types of rocks releasing toxins that seep into drinking water • Any leak at all reduces the benefits of carbon capture technology, because there is no way to recapture the leaked CO2 and store it again

36. Big Picture • Federal funding should continue so that we can learn more about the costs and risks of burying CO2 • However, “coal is the fuel of the past, not the future.” (Jeff Goodell) Clean coal technology is not a long-term solution to America’s (or the world’s) energy problems.