Energy implications of global climate stabilization

1. Energy implications of global climate stabilization Gregory Benford Physics, Univ. California, Irvine (based on the work of many, especially Marty Hoffert NYU)

2. “High technology paths to global climate stabilization”(Science Vol 298, 2002) Co-authors • Martin I. Hoffert, Department of Physics, New York University • Ken Caldeira, Energy & Environment, Lawrence Livermore National Laboratory • Gregory Benford, Department of Physics, UC-Irvine • David R. Criswell, Institute of Space Systems Operations, Univ. of Houston • Christopher Green, Department of Economics, McGill University • L.D. Danny Harvey, Department of Geography, University of Toronto • Howard Herzog, MIT Laboratory for Energy and the Environment • John Katzenberger, Aspen Global Change Institute • Haroon S. Kheshgi, ExxonMobil Research and Engineering Company • Klaus S. Lackner, Columbia University • John S. Lewis, Lunar and Planetary Laboratory, University of Arizona • H. Douglas Lightfoot, Center for Climate and Global Change, McGill University • Wallace Manheimer, Naval Research Laboratory • John Mankins, NASA Headquarters • Gregg Marland, Oak Ridge National Laboratory, • Michael E. Mauel, Dept of Applied Physics & Applied Math, Columbia University • L. John Perkins, Lawrence Livermore National Laboratory • Tyler Volk, Department of Biology, New York University • Tom M.L. Wigley, National Center for Atmospheric Research

3. Three strategies to climate stabilization Climatestabilization Diminishend-usedemand Sequestercarbon Developnon-fossilenergy sources

4. 1900 1950 2000 2150 2100 CO2 emissions = N x (GDP/N) x (E/GDP) x (C/E) = GDP x (E/GDP) x (C/E) = GDP x (C/GDP) population (N) per capita GDP (GDP/N) energy intensity (E/GDP) IPCC IS92a“Business as usual”scenario assumptions carbon intensity (C/E)

5. IN THE 20TH CENTURY: • Human population quadrupled, • * power consumption increased X 16 • Carbon Dioxide ~270 ppm ---> ~ 370 ppm • >>> will pass 550 ppm in 21st Century • Power demand reached ~ 12 TerraWatt, 85% fossil-fueled • Business As Usual Assumption: • economic growth ~ 2 - 3 % /yr • sustained decline in (Energy use/ GDP) of 1%/yr • The means to continue this rate for 100 years without greenhouse • emissions do not exist operationally or as pilot plants

6. 60 50 40 2100 Carbon-emissions-free power required (TW) 2075 30 2050 20 2025 10 2000 0 0 0.5 1 1.5 2 2.5 Rate of improvement in energy intensity (%/yr) Energy intensity decline and carbon-emissions-free power required to stabilize at 2 x CO2 We need to push hard on bothimproving energy intensity anddeveloping carbon-emissions-free power sources Greater than 1%/yr improvementmay be difficult to sustain Over 100 years, 1% / yr = 2.7 2% / yr = 7.2 2.5% / yr = 11.8 IPCC IS92a“Business as usual”scenario assumptions

7. The transportation sector Without structural changes, we can only obtain a factor of 2 improvement in the transportation sector Internal combustion18-23% efficiency Battery-electric 21-27% efficiency IC-Hybrid electric 30-35% efficiency Fuel cell 30-37% efficiency

8. Steam boiler efficiency is limited by boiler hoop strength to 40% Physical considerations limit efficiency increases. Assumptions of continuous exponential improvement are not physically justifiable.

9. 50.0 45.0 40.0 35.0 30.0 Gigatons/yr 25.0 20.0 15.0 10.0 5.0 0.0 1990 2010 2030 2050 2070 2090 Global Carbon ManagementTechnologies in the Current R&D Pipeline Are Not Enough Where today’s technology will take us IS92a(1990 technology) IS92a 550 Ceiling 1300 Gigatons Where our current aspirations for technology will take us 480 Gigatons Where we need to go to stabilize carbon

10. Energy intensity • Preliminary conclusion Without significant structural changes (i.e., changes to the way we live), it may be difficult to sustain > 1 % per year improvements in energy intensity (See Lightfoot and Green, 2001)

11. Uncertainty in climate sensitivity introduces a huge uncertainty in allowable emissions Climate sensitivity is the change inglobal mean temperature from a doubling of atmospheric CO2 Because of uncertainty in climatesensitivity, we do not know whichof these emission pathways would lead to a 2°C warming after 2150. IPCC IS92a “Business as usual” scenario (assumes 1% / yrimprovements in energyintensity) We need a major research program directed at reducing uncertainty in climate sensitivity

12. Uncertainty in climate sensitivity and carbon-emissions-free power requirements To stabilize climate,in the long term,most of our power will need to bederived from carbon-emissions-freeenergy sources Uncertainty in climate sensitivityintroduces a large uncertainty in therate at which carbon-emissions-freepower will need to be deployed 2°C warming with IPCC IS92a “Business as usual” scenario assumptions

13. Mean rate of capacity addition over next 50 years needed to stabilize climate by 2150 Uncertainty in climate sensitivity andwhat constitutes acceptable climatechange both introduce large uncertainties in the rate at which carbon-emissions-free power needsto be deployed Doing more now means doing less later, and vice versa(multiple pathsto same end). Nevertheless, amounts of carbon-emissions-freepower needed are quite large. We need a major research program directed at understanding what constitutes “acceptable climate change” IPCC IS92a“Business as usual”scenario assumptions

14. How can we diminish carbon intensity? Climatestabilization Diminishend-usedemand Sequestercarbon Developnon-fossilenergy sources

15. Carbon sequestration:A carbon-emission-free fossil-fuel economy Solving the climateproblem with sequestrationrequires a moreambitious programthan yet exists. DOE goals: 1 GtC/yr by 20254 GtC/yr by 2050

16. A Biomass Future

17. Emitted Carbon Increases as H/C Decreases

18. Forest regrowth may store carbon, but warm the world Regrowing forests storecarbon [cooling effect] butthe dark forest canopyabsorbs more sunlight[warming effect] This preliminary calculationdemonstrates the needfor systems-level analysis. We need a major research program directed at an integrated analysis of energy policy options: physics, Earth system science, engineering, economics, resource limitations, developmental paths, etc.

19. Carbon sequestration strategies Sequestercarbon Strategiesrequiring CO2or O2 separation Strategiesnot requiringseparation Geologic Oceaninjection Oceanfertilization Carbonateweathering Carbon blackstorage Silicateweathering Landbiosphere Airremoval

20. Non-fossil energy strategies Developnon-fossilenergy sources Renewable Fission Fusion Solar PV Wind Geothermal LWR Fusionbreeder Tokamaks Waves &currents Hydro He-cooledpebble bed Advanceddesigns Advanced fuel cyclesand confinement schemes

21. Solar and Wind • Storage and distribution • remain challenges • Solutions: • H2 • Global superconductingpower grid Platinum requirement for high-density electrolyzers /fuel cells to produce 10 TW = 30 x today’s global platinum mining rate

22. Fission power Known uranium reserves can provide 10 TW of power for less than 30 years --> breeder reactors Inherently safe reactor designs Proliferation Waste disposal Advanced breeding concepts Recovery of 235U from low-grade ores or seawater

23. Fusion Despite recentadvances, fusionis unlikely to be apower source inthe next 50 years Fusion as aneutron sourcefor hybrid fusion/fission breeders

24. Space options Space transmission Space solar PV Lunar solar PV Asteroid/lunar mining Geoengineering Reflect or scatter incoming solarradiation

25. Beam Power Down or Refract Sunlight Away

26. Preliminary conclusions on enabling technologies requiring additional investment • Analysis • Integrated analysis considering physics, engineering, resource limitations, environmental considerations, economics, developmental paths, etc. • Sequestration • Separation technologies • Geochemical strategies and other advanced concepts • Renewables • Global superconducting electric grid with smart load-balancing • H2 storage and distribution network • Fission • Uranium exploration technologies • Extraction of uranium from low-grade ores and seawater • Fusion • Fission/fusion breeders • Space options • Mining of asteroids and the moon • Solar power satellites

27. IPCC WG III – MitigationFailure to quantitatively address the real problem • “A broad array of technological options have the combined potential to reduce annual global greenhouse gas emission levels close to or below those of 2000 by 2010 and even lower by 2020. “ • IPCC TAR WGIII – “Mitigation” • IPCC TAR WGIII failed to • quantitatively address carbon-emissions-free power requirements beyond the Kyoto time frame • address technical, physical, and resource limitations on potential technologies

28. Develop Off-the-Shelf Albedo Changers • Whiten roofs and blacktop in cities >> saves electrical power for air conditioning, cools planet • Explore cloud production >> reflects visible, may retain infra-red • Increase clouds over tropical oceans >> couple with coal-burning plants?

29. Examples of limitations • To add 1 GW of primary power capacity each day would require • Biomass @ 5 W / m2 200 km2 land area suitable for agriculture each day • Wind @ 30 We / m2 20 km2 suitably windy land area each day [+ storage and distribution] • Solar @ 66 We / m2 5 km2 of solar cells on suitably sunny land each day [+ storage and distribution] • Fission @ one 300 MWe fission plant coming on line each day [assuming energy can be used as electricity! 1 GW if needed for heating, etc.] • If you don’t like my numbers, try this at home with your own!!! • Solutions must be applicable to developing countries, where most of the increase in emissions is expected to occur. • Ideally, we would find low-capital, safe, environmentally acceptable energy sources that could be applied on a large scale • Such energy sources do not exist [yet?]