electric cars and CO2


In the randform post about electric vehicles it was stated that electric cars are – apart from the exhaustion – not green if they don’t use renewable energies. It is however an interesting question wether they are at least a bit greener than conventional cars. The answer to this questions depends of course on what is meant by green and which cars and methods of electricity generation you are taking into account. When looking into the issue, I stumbled upon a computation by Dan Rabinowitz at homocombustans. According to an article of AP with the title: Israel focuses its energy on clean technologies there might be soon quite a lot of electric cars in Israel:

Israeli-American businessman Shai Agassi, of Project Better Place, said Israel’s small size and dense population, along with government help, made the country attractive for his firm’s network for encouraging electric cars.

He predicts that about half the cars in Israel will be electric by 2015.

Dan Rabinowitz thus computed the expected CO2 emission due to the use of an electric car as proposed by Better Place to the expected CO2 emission of a normal gasoline car.
His computation goes as follows:
According to him there are about 75% coal plants, 25% gas plants for electricity generation in Israel, he considers the renewable energy part negligable.

According to Wikipedia (without source or citation) one kwh (kilowatt hour) of electricity made with coal produces 1.47 kilogram of CO2. Rabinowitz used that number. For natural gas he uses the number
0.57 kg CO2 per kwh. (In the footnote *1) there are some other estimations for CO2 output.)

So 2700 kwh would produce 3.36 tons of CO2
[(0.75*1.47 + 0.25*0.57)*2700 = 1.245 * 2700 =3361]

According to the website at better place:

a 24 kWh lithium-ion battery (about 200 kg/440 lbs) in a competitively priced medium-sized sedan provides a range of about 160 kilometers (100 miles) on a single charge.

That is if you drive on average 18 000 kms per year then you would spend an energy of
[18000/160*24= 2700], which would produce as above computed 3.36 tons of CO2.

According to Rabinowitz this website says that a normal Renault Megane type 3 emits on average 130 grams of CO2 for every kilometre travelled. That gives 2.34 tons of CO2 [18000*0.130= 2.340 ]

Thus according to this computation an electric car fueled with electricity from the above mix of coal and gas plants produces MORE CO2 than a regular car!

As indicated in the footnote the CO2 output per kwh is a debateable factor. Lets thus see what factor you would need to have an equal output of CO2 than the Megane type 3:
2340/2700=0.87

Hence if for example if all electricity production in Israel would be from natural gas then an electric car would produce a little less CO2 than the Megane.

This gives an interesting side aspect to the Israel – Lebanon – gas – conflict as described in the article:
UN stays out of Israel-Lebanon gas dispute!

However given the very good conditions for solar energy in Israel the big question is of course why solar energy is not more pushed forward.

Footnote:
*1)According to the US report Carbon Dioxide Emissions from the Generation of Electric Power in the United States
page 3

The national average output rate for coal-fired electricity generation was 2.095 pounds CO2 per kilowatthour in 1999

page 5

The output rate for CO2 from natural gasfiredplants in 1999 was 1.321 pounds CO2 per kilowatthour.

1 pound = 0.45359237 kilograms so one has 0.95 kg CO2 per kwh for coal and 0.6 kg CO2 per kwh for natural gas according to this report.

This is more or less in accordance with numbers given in table 2 of the german study CO2-Emissionen der Stromerzeugung by Wagner, Koch and Burkhardt from the University of Bochum.

Concerning the energy mix in Israel: According to Israels major electricity company the IEC there is a power of 11.664 MW produced by fossil fuels with an energy mix which is about the one given by Rabinowitz. I couldnt find much on the installed solar energy but already judging by the AP article it seems too be much less than 11.664 MW.

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