The scientists at Argonne are not the ignorant simpletons you apparently think they are.
If you're interested in a real study (and not a chewed over report of a report of the Reader's Digest version of the abstract of a study) check this out:
http://www.ipd.anl.gov/anlpubs/2009/03/63740.pdf">Well-to-Wheels Energy Use and Greenhouse Gas Emissions Analysis of Plug-in Hybrid Electric Vehicles
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2 ELECTRICITY GENERATION MIX
A key factor in determining the environmental performance of PHEVs is the source of the electricity used to charge the battery. One goal of this analysis is to gather projections of regional generation mixes for a target year so that we can realistically examine how PHEVs will perform in different markets. The type of power plants varies by region, so it is important to examine these vehicles on a regional basis in order to better understand their effects.
A number of recent studies provided projections of the charging demand of PHEVs and matched the projected demand to the estimates of available generation capacities. These studies varied according to the regional scope and intent. Several nationwide studies produced results for all North American Electric Reliability Corporation (NERC) regions (Figure 1), while other studies were limited to specific regions. The generation mix at the time of charging became increasingly uncertain as the time for large-scale PHEV deployment increased, but the large current inventory of power plants, the availability of limited primary energy options for new plants, and the trends in costs and regulations provided guidance for projecting future plant inventories and their dispatch. By estimating the change in generating plant utilization due to PHEV load, these studies estimated the effect of PHEV deployment on reserve margins, fuel use, emissions, and costs.
2.1 FACTORS AFFECTING GENERATION MIX FOR PHEV CHARGING
The generation mix at the time of charging is a strong function of the time of day, time of year, geographic region, vehicle and charger design, load growth patterns, and the associated generation expansion in the years prior to the charging event of interest.2.1.1 Time of Day
Figure 2, developed by Shelby and Mui, is an illustration of the diurnal peaks of demand for a hypothetical summer day (Shelby and Mui 2007). Sharp summer peaks are caused by air-conditioning demand, although such peaks typically occur in the late afternoon and early evening. However, demand is at a minimum overnight when businesses are closed, lights are off, and air-conditioning load is at its lowest (Hadley 2006).
…Please follow the link (if you're actually interested in the analysis.) If you're not interested in the analysis, just assume that our national energy labs have
some grasp of the obvious. :eyes: