Sustainable Fossil Fuels? Klaus S. Lackner Columbia University April 2004

World Needs Low Cost Energy Fossil Energy contributes 80 to 90% of the total World Energy Cannot eliminate the biggest resource from the world market 10 billion people trying to consume energy as US citizens do today would raise world energy demand 10 fold

Fossil Fuels Vital For World Economy … but this does not make them sustainable

Age (years) Petit et al., Nature 399 Vostok, Antarctica Ice Core data Temperature Changes (ºC) CO 2 (ppmV) Industrial age CO 2 increase Anthropogenic increase of carbon dioxide is well documented for 20th century. Changes in the industrial age are large on a geological scale Fossil Carbon Accumulates in the Air CO 2 increase in the atmosphere accounts for 58% of all fossil CO 2 emissions

0 Gt 8,000 Gt 7,000 Gt 6,000 Gt 5,000 Gt 4,000 Gt 3,000 Gt 2,000 Gt 1,000 Gt 21st Century’s Emissions ??? Atmo- sphere 2000 Ocean Plants Coal Oil, Gas, Tars & Shales Methane Hydrates             pH < ,000 Gt 20th Century 50,000 Gt ??? Soil & Detritus 1800 constant 22 33 44 Scales of Potential Carbon Sinks Carbon Resources Carbon Sources and Sinks 20th Century

The Mismatch in Carbon Sources and Sinks 44 33 11 22 55 Fossil Carbon Consumption to date 180ppm increase in the air 30% of the Ocean acidified 30% increase in Soil Carbon 50% increase in biomass

Hydrogen economy cannot run on electricity There are no hydrogen wells Tar, coal, shale and biomass could support a hydrogen economy. Wind, photovoltaics and nuclear energy cannot.

Net Zero Carbon Economy CO 2 extraction from air Permanent & safe disposal CO 2 from concentrated sources electricity or hydrogen Mineral carbonate disposal Capture of distributed emissions

Sustainability A technology or process is sustainable at a specific scale and for a specific time, if no intended or unintended consequences will force a premature abandonment

Private Sector Carbon Extraction Carbon Sequestration Farming, Manufacturing, Service, etc. Certified Carbon Accounting certificates certification Public Institutions and Government Carbon Board guidance Permits & Credits

CO 2 extraction from air Permanent & safe disposal CO 2 from concentrated sources Net Zero Carbon Economy

Lake Michigan 21 st century carbon dioxide emissions could exceed the mass of water in Lake Michigan

Short Term Answers Enhanced Oil Recovery Coal Bed Methane Extraction Injection into abandoned wells Injection into deep saline reservoirs Ultimately carbonic acid must be neutralized

Constraints on Disposal Methods Safe Disposal Minimum Environmental Impact No Legacy for Future Generations Permanent and Complete Solution Economic Viability 5000 Gt of C 200 years at 4 times current rates of emission Storage Slow Leak (0.1%/yr) 5 Gt/yr for 1000 years Current Emissions: 6Gt/year Economically tolerable: 1 cent/kWh $20/t of CO 2 Nuclear Energy Limit: $60/t of CO 2 $10/ton of CO 2 :  8.5¢/gallon Fast leaks are catastrophic (Lake Nyos) Slow leaks cause greenhouse emissions Dilution causes irrevocable change

Energy States of Carbon Carbon Carbon Dioxide Carbonate 400 kJ/mole kJ/mole The ground state of carbon is a mineral carbonate

Net Carbonation Reaction for Serpentine Mg 3 Si 2 O 5 (OH) 4 + 3CO 2 (g)  3MgCO 3 + 2SiO 2 +2H 2 O(l) heat/mol CO 2 = kJ Accelerated from 100,000 years to 30 minutes

Magnesium resources that far exceed world fossil fuel supplies

Rockville Quarry

1 GW Electricity ~35 kt/day ZECA Process ~1.4 kt/day Fe ~0.2 kt/day Ni, Cr, Mn 4.3 kt/day Heat Coal Sand & Magnesite Open Pit Serpentine Mine CO 2 11 ktons/day Coal Strip Mine Coal Strip Mine Zero Emission Coal Power Plant 70% Efficiency Zero Emission Coal Power Plant 70% Efficiency Earth Moving ~40 kt/day Mineral Carbonation Plant 28 kt/day 36% MgO Mining, crushing & grinding: $7/t CO 2 — Processing: $10/t CO 2 — No credit for byproducts

Serpentine and Olivine are decomposed by acids Carbonic Acid - Requires Pretreatment Chromic Acid Sulfuric Acid, Bisulfates Oxalic Acid Citric Acid …

ALBANY’S SUCCESS 200,000 years reduced to 30 minutes W.K. O’Conner, D.C. Dahlin, D. N. Nilsen, R. P. Walters & P.C. Turner Albany Research Center, Albany OR Suggests simple cost-effective implementation Mg 3 Si 2 O 5 (OH) 4 +3CO 2 (g)  3MgCO 3 +2SiO 2 +2H 2 O(l)

Acid Recovery: Solvay Process Neutralize with ammonia Recover through heating

CO 2 extraction from air Permanent & safe disposal CO 2 from concentrated sources Net Zero Carbon Economy

CO 2 N 2 H 2 O SO x, NO x and other Pollutants   Carbon Air Zero Emission Principle Solid Waste Need better sources of oxygen Power Plant

CaO as an enthalpy carrier CaCO 3 + heat  CaO + CO 2 O 2 + 2H 2  2H 2 O kJ CaO + C + 2H 2 O  2H 2 + CaCO kJ C + O 2  CO kJ Compare to kJ Output kJ

Zero Emission Coal CO 2 H2OH2O H2OH2OH2OH2O H2OH2O H2OH2O CaCO 3 CaO H2H2 H2H2 H2H2 CH 4, H 2 O Air N2N2 Coal Slurry Gasifier De- carbonizer Calciner Fuel Cell Gas Cleanup Polishing Step Ash Cleanup CaO + C + 2H 2 O  CaCO 3 + 2H 2 Lime/Limestone Cycle Heat Closed Cycle for Gas

CO 2 extraction from air Permanent & safe disposal CO 2 from concentrated sources Net Zero Carbon Economy

Air Flow Ca(OH) 2 solution CO 2 diffusion CO 2 mass transfer is limited by diffusion in air boundary layer Ca(OH) 2 as an absorbent CaCO 3 precipitate

CO 2 1 m 3 of Air 40 moles of gas, 1.16 kg wind speed 6 m/s moles of CO 2 produced by 10,000 J of gasoline Volumes are drawn to scale

Wind area that carries 22 tons of CO 2 per year Wind area that carries 10 kW 0.2 m 2 for CO 2 80 m 2 for Wind Energy How much wind? (6m/sec)

Biomass 3 W/m 2 Sunshine 200 W/m 2 Wind Energy v = 6m/s 130 W/m 2 Extraction from Air Power Equivalent from gasoline v = 6 m/s 60,000 W/m 2 Areas are drawn to scale

60m by 50m 3kg of CO 2 per second 90,000 tons per year 4,000 people or 15,000 cars Would feed EOR for 800 barrels a day. 250,000 units for worldwide CO 2 emissions

Boundary Layer

Wind Energy - CO 2 Collection Wind Energy Convection tower, Wind Mill etc. Extract kinetic energy Wind Turbines 30% extraction efficiency Throughput 130W/m 6m/s wind Cost $0.05/kWh CO 2 Collection Convection tower, absorbing “leaves”, etc. Extract CO 2 Sorbent Filters 30% extraction efficiency Throughput 0.64g/(s·m 2 6m/s wind Cost by analogy $0.50/ton of CO 2 Additional Cost in Sorbent Recovery

A First Attempt Air contactor: 2Na(OH) + CO 2  Na 2 CO 3 Calciner: CaCO 3  CaO+CO 2 Ion exchanger: Na 2 CO 3 + Ca(OH) 2  2Na(OH) + CaCO 3

Objections CO 2 in air is too dilute Cross section of structure is affordable Binding energy of sorbent scales logarithmically  G = RT log P/P 0 Liquid absorbers will saturate Energy consumption diverges Cost of sorbent recovery CaCO kJ  CaO + CO 2 CaO + H 2 O  Ca(OH) kJ

15 km 3 /day of air As electricity producer the tower generates 3-4MW e 15 km 3 /day of air 9,500t of CO 2 pass through the tower daily. Half of it could be collected 9,500t of CO 2 pass through the tower daily. Half of it could be collected 300m 115m Cross section 10,000 m 2 air fall velocity ~15m/s Water sprayed into the air at the top of the tower cools the air and generates a downdraft.

Any design that moves air can be used for CO 2 capture Cooling Tower Design Diameter ratio of smoke stack to capture tower is 300 1/2 =17

Exotic Designs

Process Schematic Capture Device Trona Process Limestone Precipitate Dryer Fluidized Bed Hydroxylation Reactor Combined Combustion- Separation (1) (2) (3) (6) (5) Solid Oxide Membrane NaOH Na 2 CO 3 Ca(OH) 2 CaCO 3 CO 2 H 2 O Air (O 2, N 2 ) CH 4 CaCO 3 H2OH2O O2O2 Source: Frank Zeman CaO Oxygen Depleted Air (4)

Net Zero Carbon Economy CO 2 extraction from air Permanent & safe disposal CO 2 from concentrated sources electricity or hydrogen Mineral carbonate disposal Capture of distributed emissions

Energy Source Energy Consumer H2OH2O H2OH2O O2O2 O2O2 H2H2 CO 2 H2H2 CH 2 Materially Closed Energy Cycles

Sustainable on indefinite time scales