one would then have to factor in the future, rather than the current 'now', of our electrical infrastructure.
California seems to be a leader in upgrading to renewable sources, and has always been at the forefront
of more stringent emission requirements for autos and trucks.
I would suggest that the overall cost per mile favors electricity regardless of it's source, considering the 'full' price
of a gallon of gasoline.

https://www.treehugger.com/solar-technology/solar-electric-car-charging-stations-fuel-sunshine.html
http://www.plugincars.com/ultimate-guide-electric-car-charging-networks-126530.html
Maybe a 'zero-er' emission frame would be more accurate.
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"The shift is possible in California partly because theres a surplus of solar power, after a surge of rooftop panels and large-scale gathering systems helped double the renewable energy it used over the past decade. Batteries can charge up in daylight and dispense electricity later. With improved technology and lower costs, storage systems are becoming more viable for utilities, especially in a state hoping to get half its power from wind and solar by 2030 and targeting major cuts in greenhouse gas emissions.
California is going to create a blueprint for the coming years, said Michael Ferguson, the director of U.S. energy infrastructure at S&P Global Ratings in New York. Renewables proliferated where there was supportive regulation, and that caused the costs to decline. I would expect to see the same thing to happen with battery storage.
While natural gas became the biggest source of power in the U.S. two years ago -- it burns cleaner and more cheaply than coal -- regulators are looking to reduce carbon emissions to combat global warming and climate change. Gas now accounts for about a third of the countrys electricity, but renewables like solar and wind are expanding faster, doubling their share of the market over the past decade to a projected 17 percent last year, government data show."<
https://www.msn.com/en-us/money/markets/a-new-era-of-batteries-spells-trouble-for-gas-in-america/ar-AAuzerv?li=BBnbfcN