Potential Wedges
  Option Effort by 2054 for one wedge, relative to 14 gigatons of carbon per year (GtC/year) BAU
Energy Efficiency and Conservation Economy-wide carbon-intensity reduction (emissions/$GDP) Reduce by additional 0.15% per year
1. Efficient vehicles Increase fuel economy for 2 billion cars from 30 to 60 mpg
2. Reduced use of vehicles Decrease car travel for 2 billion 30-mpg cars from 10,000 to 5,000 miles per year
3. Efficient buildings Cut carbon emissions by one-fourth in buildings and appliances projected for 2054
4. Efficient baseload coal plants Produce twice today's coal power output at 60% instead of 40% efficiency (compared with 32% today)
Fuel Shift 5. Gas baseload power for coal baseload power Replace 1,400 GW 50%-efficient coal plants with gas plants (4 times the current production of gas-based power)
CO2 Capture and Storage (CCS) 6. Capture CO2 at baseload power plant Introduce CCS at 800 GW coal or 1,600 GW natural gas (compared with 1,060 GW coal in 1999)
7. Capture CO2 at H2 plant Introduce CCS at plants producing 250 MtH2/year from coal or 500 MtH2/year from natural gas (compared with 40 MtH2/year today from all sources)
8. Capture CO2 at coal-to-synfuels plant Introduce CCS at synfuels plants producing 30 million barrels per day from coal (200 times Sasol), if half of feedstock carbon is available for capture
   Geological storage Create 3,500 storage projects
Nuclear Fission 9. Nuclear power for coal power Add 700 GW (twice the current capacity)
Renewable Electricity and Fuels 10. Wind power for coal power Add 2 million 1-MW-peak windmillls (50 times the current capacity) "occupying" 30x10-to-the-sixth ha, on land or off shore
11. PV power for coal power Add 2,000 GW-peak PV (700 times the current capacity) on 2x10-to-the-sixth ha
12. Wind H2 in fuel-cell car for gasoline in hybrid Add 4 million 1-MW-peak windmills (100 times the current capacity)
13. Biomass fuel for fossil fuel Add 100 times the current Brazil or U.S. ethanol production, with the use of 250x10-to-the-sixth ha (1/6 of world cropland)
Forests and Agricultural Soils 14. Reduced deforestation, plus reforestation, afforestation and new plantations Halt tropical deforestation instead of 0.5 GtC/year, and establish 300 Mha of new tree plantations (twice the current rate)
15. Conservation tillage Apply to all cropland (10 times the current usage)

CCS = carbon capture and storage
GtC = gigatons of carbon
GW = gigawatts
ha = hectare
Mha = million hectare
Mpg = miles per gallon
MW = megawatts
PV = photovoltaics
Source: Princeton University's Carbon Mitigation Initiative.
Last updated: January 30, 2007