Equivalent Volt and Tesla Pollution Mileage in Various California Utility Districts

Electric cars do not run on manufacturers mpg ratings, nor on the mysterious EPA mpg ratings.  They run on electricity provided mostly at night provided by your local utility.  We give here the amount of CO2 produced per kWh from the US average, the California average, and the main California utilities.  For each electric car’s efficiency in getting miles out of a kWh, we translate the amount of CO2 produced in each utility to each mile traveled in an electric car. Then we can divide by the 20 pounds of CO2 produced by a gallon of gas, to get the equivalent mpg of an electric car in terms of the CO2 produced.

 

We start with the CO2 produced for 1000 kWh by burning natural gas at 34% efficiency in a typical natural gas plant.  Natural gas produces 399 pounds of CO2 for 1000 kWh if burned at 100% efficiency.  If burned at 1/3 efficiency, we need to burn 3 times the natural gas producing three times the 399 pounds CO2, or about 1200 lbs CO2 for 1000 kWh.  More precisely, it is 1.17 lbs CO2 per kWh.

 

In the previous article on California utilities, the standard scale 1 was for CO2 pollution from natural gas at 34% efficiency.  The Total for each utility just has to be scaled up by 1.17 lbs CO2 per kWh to give the lbs CO2 per kWh of that utility.  We will give a table of those values.

 

We will look at the Chevy Volt in its electric range, and the fully electric Tesla Model-S as examples, since they are the most popular electric cars.  The Chevy Volt 2016 2nd Generation has a 18.4 kWh battery with electric range of 53 miles.  That makes 2.9 miles per kWh.  The reverse of this is 34.7 kWh per 100 miles, or 0.35 kWh per mile. This is a lot less than the 4 miles per kWh I used in my 2009 analysis.  Over 100,000 Chevy Volts have been sold.

 

The Tesla Model-S has a 70 kWh battery with 240 mile range given by the EPA.  That gives 0.292 kWh per mile or 29.2 kWh per 100 miles.  We use this more efficient model in the table.  There is also an 85 kWh with a 265 mile range.  That gives 0.321 kWh per mile or 32.1 kWh per 100 miles.  The reverse is 3.12 miles per kWh.

In the last 4 quarters, 43,000 Tesla Model-S cars have been sold.  In the table, we use the smaller 70 kWh battery at 0.292 kWh per mile.

 

In the table we keep separate the unspecified power until the mpg columns, where we just add in the undetermined power as if it were natural gas power.  We round off to the nearest 5 mpg, considering the large undetermined power in some utilities.

 

 

 

 

 

 

 

 

Utility Lbs CO2/kWh Volt Lbs CO2/mile Volt mpg Tesla Lbs CO2/mile Tesla  mpg
US 1.13 0.39 50 0.33 60
CA 0.67+0.18 0.23+0.06 70 0.20+.05 80
SCE 0.32+0.47 0.111+0.163 75 0.093+0.137 85
PG&E 0.28+0.25 0.10+0.09 105 0.08+0.07 130
LADWP 1.09+0.08 0.38+0.03 50 0.32+0.023 60
SDG&E 0.56+0.23 0.20+0.08 70 0.18+0.07 80
SMUD 0.48+0.09 0.167+0.03 100 0.140+0.026 120
SFPUC 0.00 0.00 Clean Clean Clean
Silicon Valley 0.74-0.06 0.26-0.02 85 0.216-0.017 100

 

About Dennis SILVERMAN

I am a retired Professor of Physics and Astronomy at U C Irvine. For two decades I have been active in learning about energy and the environment, and in reporting on those topics for a decade. For the last four years I have added science policy. Lately, I have been reporting on the Covid-19 pandemic of our times.
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