Life cycle analyses suggest that electric vehicles are more efficient than
gasoline internal combustion engine vehicles (ICEVs). Although the latest
available data reveal that electric vehicle (EV) life cycle operational
efficiency is only 17% (3 percentage points) higher than a gasoline ICEV,
overall life cycle efficiencies including manufacturing for EVs are 2 percentage
points lower than for ICEVs. Greenhouse gas (GHG) emissions of EVs are only 4%
lower than ICEVs, but criteria emissions of NOx and PM are
approaching or exceeding two times those of gasoline ICEVs. Significant
reductions in electric grid emissions are required to realize EV’s anticipated
emission benefits. In contrast, hybrid electric vehicles (HEVs) have over 70%
higher efficiency and 28% lower GHG emissions than today’s EVs. For heavy-duty
trucks using today’s gray hydrogen, produced by steam–methane
reforming, overall life cycle efficiencies of ICEs and fuel cells are 63% higher
than electric powertrains using today’s electric grid, but 25% lower than
diesel-fueled ICEs. GHG emissions of ICEs and fuel cells using
gray hydrogen are 34% lower than electric powertrains using
today’s grid, but are over 50% higher than diesel-fueled ICEs. Only 1% of
today’s hydrogen is green, derived by electrolysis using
renewable energy. Using green hydrogen, life cycle efficiencies
of ICEs or fuel cells are 36% lower than with gray hydrogen.
GHG emissions of green hydrogen-fueled ICE or fuel cell
powertrains, although reduced by 69% relative to gray hydrogen,
are nearly twice those of an electric powertrain using renewable
electricity.
