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In the near-term (between now and 2020), converting natural gas to hydrogen for use in a FCEV will reduce greenhouse gas pollution by approximately 51%. If that natural gas is burned in an optimized NGV, the GHGs would be reduced by only 22%; thus natural gas converted to hydrogen in a FCEV cuts GHGs approximately 2.3 times more than using that natural gas in an optimized NGV:
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Near-term GHGs (g/mile)
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Savings (g/mile)
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ICV
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405
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NGV
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316
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-89
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FCEV
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197
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-208
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In the long term, FCEVs have even greater advantages, since hydrogen can be made from a variety of low- or zero-carbon sources such as biomass, solar, wind, waste water or nuclear energy, etc., while NGVs will continue to generate GHGs. The bar-chart below shows the estimated well-to-wheels GHGs for NGVs and for FCEVs in 2050 and 2100 from our 100-year simulation program. The red line indicates the 1990 level of GHGs from the US light duty vehicle sector, and the green line shows the goal: an 80% reduction below 1990 levels. The FCEV is the only option that could achieve that goal, reducing GHGs by 89% by 2100. The second-best option would be a natural gas plug-in hybrid electric vehicle (NG PHEV) which would cut GHGs by only 47%. Note that optimized NGVs and even natural gas hybrid electric vehicles (NG HEVs) would increase GHGs by +41% and +29% relative to 1990 levels by the end of the century due to the assumption of increased vehicle miles traveled (VMT).
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The estimated changes in GHG levels in 2100 relative to 1990 levels are summarized in this chart:
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