Wednesday, November 21, 2007

Gasoline Vs. Electricity

I think that in this day and age there are a lot of things open to debate -- from embryonic stem cells to abortion to the war in the Iraq -- where either side of the argument probably has a valid point. When debating some of these alternatives to gasoline for cars, it's hard to debate the numbers and I think it'll go a long way to helping America choose the right choice for the future if more people can be informed so...
If you guys want to check the numbers and/or the math, feel free. They came from the Department of Energy's web site and I corroborated them from other sites as well: (Bare with me)...
To accurately debate the benefits of electric powered cars (not hybrids that create electricity by the braking of the car which is different and good), you need to consider two factors... CO2 emissions and cost. So, what I did first was to look up the average CO2 emissions for America (since this is an average it includes huge nuclear power plants such as Palos Verde in Arizona, wind, water, and of course, coal power plants so I think the actual number for coal fired power plants would be higher) The amount of CO2 emitted per Kilowatt hour is 2.117 pounds of CO2 per KWH (kilowatt hour). Next, I found the average price per KWH of electricity in the United States, which comes out to 9.86 cents per KWH. So, so far for electricity we have:

2.117 pounds CO2 per KWH
9.86cents per KWH

For gasoline, the AAA national average is $3.28 per gallon. The CO2 emissions per gallon of gasoline is 19.4 pounds per gallon. Again, these values are very easy to look up on the internet. So for gasoline:

19.4 pounds CO2 per gallon
$3.28 per gallon

So, the only hard part is to convert KWH into gasoline so that price and CO2 emissions could be compared. This was done by looking up the conversion factor. After confirming with several websites (including the Department of Energy's), the conversion factor is

1 gallon gasoline = 36.3 KWH

Next, I converted the numbers:

2.117 pounds/KWH (36.3 KWH/gallon) = 76.83 pounds/gallon

9.86 cents/KWH (36.3 KWH/gallon) ($1/100cents) = $3.58 per gallon

To sum up, if you were to power your car entirely using electricity at this point in time, you would increase your CO2 emitted per distance traveled on a gallon from 19.4 pounds of CO2 to 76.83 pounds. Almost four times MORE. And, it would cost you more.
Now, this is not to say that I don't think electric powered cars is a good thing. I already mentioned the differance in hybrid technology that allows powering the car by breaking (which does not involve CO2 emission). But a lot of people don't realize that with electricity you're not getting something for free. Although I probably shouldn't have let it bother me, your comments this afternoon did hurt. I have to put up with a lot of criticism of ethanol everyday from my peers and not a lot of encouragement. (Some of the criticism is warranted but a lot involves people not being aware of the facts, as seen above). Everyone understands that the solution to environmental concerns and energy security for the United States will not be solved ONLY with ethanol, or any one energy for that matter, but we also can't afford to have knee jerk reactions just because electricity seems safe and free of emissions. I hope the numbers above clear some of that up and frame the debate a little better. As technology increases, power plants will pollute less but may cost more, which will prevent developing nations from being able to consider $3.58 per gallon electricity that we have now.

1 comment:

Anonymous said...

You forgot to consider the mechanical efficiencies of the vehicle. Internal combustion engines are very inefficient. Very few of the KWh in a gallon of gasoline are actually converted to forward movement. The rest is lost as heat. Do a little research