Here is an interesting document about plug-in hybrid vehicles (PHEV):
Air Emissions Impacts of Plug-In Hybrid Vehicles in Minnesota's Passenger Fleet
http://www.state.mn.us/mn/externalDocs/Commerce/Air_Emissions_Impacts_of_PlugIn_Hybrid_Vehicles_in_Minnesotas_Pass_032907013010_PCA_PHEV_emissions_FINAL_2.pdf
Fig. 3 and Table 5 show that with 100% of electricity generated with
coal, a plug-in hybrid electric car with a 60 mile range would
generate more CO2 per mile than a conventional car. However, most
Minnesota and most other states have a mixture of coal and other electricity.
Most of this document models a state with 60% electricity generated
by coal. This is appropriate because in Minnesota, 64% of power comes
from coal. See:
http://tonto.eia.doe.gov/state/state_energy_profiles.cfm?sid=MN
Taking into account the electricity generated from natural gas, I
suppose the total fossil fuel is ~70%, and from Table 5 I estimate
carbon emissions for at 60-mile PHEV would be lower by about 25%
(halfway between 80% and 60%. However, by the time PHEV become widely
used, I expect Minnesota will install many more wind turbines, so
total fossil fuel electricity will be down to around 60% (meaning
that PHEV will reduce CO2 by 34%), or possibly even 50% (reducing CO2
by 51%). Minnesota is the #4 state in wind energy, and it is
expanding rapidly. (http://www.awea.org/projects/minnesota.html)
You can see that in California, where coal is hardly used, PHEV would
greatly reduce CO2. In California, they generate 9 times more power
from wind and "other renewables" than from coal. See
http://tonto.eia.doe.gov/state/state_energy_profiles.cfm?sid=CA
This document lists good sources from EPRI and elsewhere.
- Jed
