Gasoline car or electric “coal powered” car
I have read through multiple threads in which the question arises, which is better, a gasoline powered engine or an electrically, coal powered engine. I ran some pretty rough numbers and was surprised to find that coal produces four times the CO2 as a gasoline powered car. I was expecting it to be the other way around. Below I have my assumptions and calculations, so please point me in the right direction if I made any glaring errors or any really poor assumptions. I would definitely appreciate some help in refining this extremely crude model. It is obvious that other factors need to be discussed (other pollutants, transmission, etc.), but I could only track down numbers for CO2 (mainly when dealing with the car).
I used a Honda Fit as my car, which has a 109 HP (81KW) engine and has a highway mileage of 7.8L/100km (according to the Honda website). Now, I assumed that the electric version would use an electric motor of the same size (is this a horrible assumption? I feel like this is where my major error may be, as I really know nothing about electric motors . . .). I assumed the car drove 100km at a highway speed of 100km/hour.
I also assumed that gasoline was purely octane, and that only the stoichiometric amount of oxygen was introduced to the engine, with no excess. I assumed complete combustion, meaning the only products were CO2 and water.
Gasoline:
So the balanced chemical equation is:
C8H18 + 25O2 -> 8CO2 + 9H2O
The car burned 7.8L x octane density (0.91786kg/L) = 7.16kg of fuel
The molar mass of octane is 114.18kg/kmol, therefore 0.0627 kmol of octane were burned. Multiply by 8, and 0.5016 kmol of CO2 was produced. Multiply by the molar mass of CO2 (44kg/kmol) we get 22.07 kg of CO2 was produced.
Coal:
I used the Nanticoke coal facility (North America’s largest, yay Ontario!) as my power plant. In 2005 (easiest to find figures), it produced 17,851,406 MWh of electricity (can be found at http://www.IESO.ca/) and approximately 17,585,856,000 kg of CO2 (http://www.cleanair.web.ca/resource/opggiant.pdf). Therefore it produced 985 kg/MWh. The car above would use 81 kWh to go 100km in one hour, therefore it would “produce” almost 80 kg of CO2
Summary:
Gasoline powered car produces 22.07 kg of CO2 was, and the “coal power” car produces 80 kg of CO2.
If someone is able to really help refine this, the data from the Ontario Government for the other pollutants emitted from Nanticoke in 2005 (to produce 17,851,406 MWh) are:
CO -> 7,291,800 kg
NOx -> 23,171,155 kg
PM -> 6,722,976 kg
PM10 -> 2,124,484 kg
PM2.5 -> 665,588 kg
SO2 -> 67,946,900 kg
VOCs -> 260,059 kg
Source: http://www.treehugger.com/