Environmental Benefits of Flexible Fuel Plug-Ins
Less Greenhouse Gases and Smog
Plug-in hybrids could give millions of American commuters a “gasoline-free”
daily commute, slashing the amount of greenhouse gases and other pollutants
being released into the environment.
The air quality benefits would be magnified if plug-in hybrids were combined
with already existing flexible fuel technology. Flexible fuel plug-in
hybrids would also benefit American agriculture.
Additionally, plug-in hybrids, like conventional hybrids, don’t
idle when sitting still. Estimates are that in urban driving, idling translates
to about 10%-15% of total vehicle carbon emissions.
Utilities Have the Electric Capacity
Over 40% of the generating capacity in the U.S. sits idle or operates
at a reduced load overnight, when most PHEVs would be charged. That means
tens of millions of plug-ins could be charged every night without the
need to build additional electric generation capacity. For example, Southern
California Edison, an investor-owned utility, estimates that 4 million
plug-in hybrids could be charged without exceeding its existing peak load.
Millions more could be fueled within existing capacity.
Emissions Decrease With Hybridization
A study by the Electric Power Research Institute (EPRI) found that “emissions
decrease with increasing degree of hybridization”— meaning that
conventional hybrids emit less pollution than conventional vehicles while
plug-in hybrid vehicles emit less pollution than current hybrids. The study
concluded that widespread use of plug-in hybrids would bring significant
reductions in both greenhouse gases and smog inducing pollutants. The study
was a “well-to wheels” analysis, meaning it took into account
emissions from oil extraction, transportation, refining and distribution.
For plug-in hybrids, the emissions generated from power plants in charging
the vehicles is included. (Partners in the study included automakers, the
Department of Energy, and air quality districts*.)
Well-to-Wheels Greenhouse Gas Emissions
 Source: Electric Power Research Institute (EPRI) |
The “well-to-wheels” data is based on the electricity being
generated by natural gas-fired combined cycle turbines. According to EPRI,
natural gas plants adapt the easiest to marginal increases in power demand.
* The EPRI study group included The California Air Resources
Board; the Department of Energy and two of its national labs (National
Renewable Energy Laboratory and Argonne National Laboratory); General
Motors; Ford; South Coast Air Quality Management District; the University
of California Hybrid Vehicle Center; Southern California Edison; New York
Power Authority and Southern Company.
PHEVs Increase Development of Wind Energy
In the case of Austin Energy and that of many other utilities, the use
of flexible fuel PHEVs will mean harnessing more wind power. A significant
portion of Austin Energy’s wind power comes from the West Texas
wind at night during off peak times. This electricity cannot currently
be stored. Since PHEVs will be charged mostly at night, plug-in hybrid
batteries could serve as storage until the car is used. This could lead
to increased development of wind energy.
Emission Comparisons:
Wind-driven Electric Gallon of Gasoline
Table data based on 12,500 miles/year |
What if the power were generated by coal?
As discussed above, natural gas will likely be used to fuel plug-in
hybrids where available because natural gas plants adapt best to marginal
increases in load. Also, wind power works well for plug-ins because much
wind electricity is generated at night when plug-ins would be charged.
Further studies are being done on the cumulative emissions impact if
electricity for plug-in hybrids is generated by coal. It is already apparent,
however, that powering plug-ins, even with coal, would be cleaner in almost
every area of the country, if not every area.
Additionally, emissions would be concentrated in one location that is
often away from critically-endangered air sheds. Also, it is less difficult
to control emissions from a relatively few number of smokestacks rather
than millions of vehicle tail pipes. And, efforts to clean up coal plants
and other emissions will continue.
In fact, over the last 25 years emissions from U.S. power plants have
decreased by 25%. This has been done through retiring old power plants
and incorporating cleaner generation technologies. This trend is expected
to continue so emissions will continue to get cleaner over time, meaning
emissions generated from electric transportation will get cleaner over
time. |