Hello, back to Energy 101, and today we're going to talk about electric car carbon
emissions. In my introduction somewhere on my, main
page for this course I made the statement that electric cars do not save carbon
emissons. I put that on there to be controversial,
and it certainly did create a lot of controversy.
It got more comments than almost any other topic, which was good.
That's what I meant for it to be. And it is a controversial statement.
But the reason that I put that up there and the reason I addressed this is, I was
always amazed that the electric car manufacturers, this happens to be a photo
of a Leaf, got emblems on it that says zero emissions.
And Ifelt like that might be a little misleading.
The zero I feel is misleading, now it does have zero tail pipe emissions because it
doesn't have a tail pipe. No question, but, let's drill a little
deeper and see if when you buy an electric car, if you really, when you drive it are
you really, producing zero carbon emissions then like I said, I'm taking a
particular case, and you can debate the zero statement.
You can always come up with a scenario in which the zero is, is true.
But let's look at the one that I feel like is, is the appropriate one from a public
policy viewpoint. And when you look at it from an individual
viewpoint, it can be different. But the question, do all-electric cars
have 0 emissions? View from the US or, are, do they reduce
emissions is the probably a more nuance question.
It definitely is a more nuance question. But I want to take the view from a US
public policy viewpoint, not. From a personal or regional viewpoint.
So, when I say public policy how much do current tax incentives that put more
electric cars on the road throughout the US, all over the US reduce CO2 for the US?
Because it's an, it's a international problem.
So emmisions that are produced in California affect New York and Florida
then vice versa. So as a, we need to look at it from an
energy policy and global warming policy viewpoint, from a national perspective.
So, not from an individual or regional perspective.
You can get a different ansewr if you look at a personal situation, where if you're
off the grid, for instance. And getting all your electricity from
solar or wind, the answer is you burn damn close to zero, okay.
No question about that. Nobody can debate that I don't think, if
your off the grid getting it from renewable energy.
But, that's not the typical situation I would contend if I hadn't run the number
that is probably less than 1/10 of 1%. And 99.9% are going to get it from the
grid. So let's try to answer that question.
Well, number one we have to look at, where does the electric car energy come from.
And, when you, you plug it in to recharge it, and it gets no, no energy from
gasoline, you don't have a gasoline tank, and we're talking about all electric cars
here, ones that run totally on electricity like the Leaf.
The Leaf is a I keep using that example because that's the first really
mass-produced electric car by a major international car manufacturer, such as
Nissan, as the Leaf is. But all the energy comes from the electric
grid. None of it comes from electricity.
The Chevy plug in hybrid as we've talked about is, is different.
It gets some from gasoline, some from electric grid.
The Prius that's strictly a hybrid that's been out for 10 years it gets all of it's
electricity from gasoline. We'll talk about that.
But the electricity generated for charging the batteries does create CO2 at the
electrical power plant. In general when you're looking at the grid
as a whole some of that electricity going into that grid has been generated by
fossil fuels that emit CO2. So let's dive a little deeper in this, and
see, and see. How we can calculate this number.
We've gotta make assumptions along the way, and you can change the number of, of
different assumptions. So, it's a great, great question for
discussion and calculation for a discussion that depends on the assumption.
So I'm going to give you my assumptions here, hopefully.
But how much if, we want to look at how many kilowatt-hours are required to drive
the electric car one mile, that's the first thing we need.
We need to know how much electricity has to be generated, and put into the grid,
due to the fact that we now just bought an electric car, or bought 1,000,000 of them,
and put them on the grid. Well, the, the Leaf, according to US, EPA
it's, it's like fuel mileage that they quote.
Usually is about 1/3 of a kilowatt hour per mile, 1/3 of a kilowatt hour per mile
and that inverted means it, it gets about three miles for every kilowatt hour used.
Three miles for ever kilowatt hour used. So somewhere, when you generate a kilowatt
hour it will drive you approximately three miles, and by the way, these kinds of
calculations, you can debate plus or minus 10% on any of these numbers.
You can debate plus or minus 20%, so... I don't try, I try to stay out of the
fractions and decimal points and those kind of things, because we're trying to
look at the big picture and reach a big policy decision question here.
So, but the next thing, so the next thing we need to know.
Is, how much CO2 is emitted for each of those kilowatt-hours that is generated and
put into the grid, for that, battery to be charged, in our, electric car.
Well, if you take the total CO2 emissions, and the, carbon emissions from power
plants All power plants, and that. You get that number.
I got that number, from EIA, Energy Information Agency, the, off the web.
Then divide it by the total US kilowatt hours delivered.
Then that gives you pounds or grams of, of CO2 per kilowatt hour produced and put
into the grid. And by the way, the, I, the number comes
out to about, to 1.2, approximately 1.2, 1.12, 1.3, 1.23, 1.818, is, is in that
ballpark, which by the way is 545 grams per kilowatt hour.
So, so that means then that the pounds of CO2 produced per mile driven in your
all-electric car, that gets a third of, of a, I think it's three miles per
kilowatt-hour, such as the Leaf. Is 1.2 pounds divided by 3 miles per
kilowatt hour, or .4. So you've got about, the electric car, the
Leaf type, will get about .4, or produce about .4 pounds of CO2 at the power plant
to generate the electricity to carry the car about one mile.
Now, that's the sum total of the ceo2 produced by all the power plants that feed
into the grid that you're charging the battery off of.
Now, we need to look at the gasoline driven so we can compare it.
What's the gasoline driven car co2 emissions?
Well, you can look it up again on e-, e-, Energy Information Agency, which is where
90 or 98% of my data comes from it's a very dependable source.
And it comes out to about 19.6 pounds of CO2 per gallon of fuel burned.
19.6 si, a pound per gallon of fuel[INAUDIBLE].
It's kind of interesting, a gallon of fuel wry, weighs only about 6 pounds but it
produces 19 1/2 pounds of C02. And of course the reason for that is, the
gasoline is made up of C Carbon and hydrogen.
And then you take the oxygen out of the air and that oxygen reacts with the
hydrogen. So, now you've added oxygen to the carbon.
And that, that mass is higher than the original carbon and hydrogen that we use
to begin with. But, That, now, if you, know the miles per
gallon. That, that car gets, then we can calculate
the CO2 emitted per mile driven by the gasoline car.
And so if you, you just take 19.6 pound of CO2 per gallon and divide it by the miles
per gallon of that particular car. So in order to get equivalent, you can
play around with it and calculate it exactly, but essentially, if you take a
pri, prius hybrid that runs totally on gasoline, it generates some electricty
for, for itself when charges a small batteries when you come to a stop due to
breaking and uses it back. When you, start back up, but it gets none
external, no electricity external from the car at all.
It gets all it's energy to drive on gas, from gasoline.
And you come out with about .4 pounds per mile.
Well, I use the 50 because it's about equivalent to the leaf to the electric
car, and so, So the, and they are similar sized cars, similar performance.
There's not a heck of a lot of, I don't think someone a person shopping for a, for
a Leaf, is going to be also considering a GMC Yukon, or something.
A big SUV. So you gotta, you gotta compare apples to
apples here, I think to have a rational number in my mind.
So is US av. The next question though to ask, is the US
average co2 emitted per kilowatt hour the proper value to use?
That I came up with the 1.2, remember, I just took the total CO2 produced by all
the power plants. And divided by the total kilowatt hours
produced by all power plants. Well, I claim that that's probably not the
right value, because it's too low, due to dispatching issues.
In an electric car, it's mostly charged overnight.
And there are lots, there's lots of excess power capacity at night, probably.
And some people argue we've got to build more power plants, to, meet, the cap, the,
charging need for all these electric cars. But that's not true, since most of them
are going to be charged at night, and we have low demand at night.
And there's plenty of power plant capacity to, to meet the increase charging demand
from these new electric cars that we're putting on.
But, the incremental electricity will not come from renewables, is one strong
argument that you can make. Because they're already being utilized
100%, so when you put an incremental load of one electric car, or a million electric
cars, onto the grid, you're not going to get anymore electricity renewal just
because you're using all that anyway. The economics demand it.
The real operation demands it. You just don't turn off wind turbines.
You take the electricity any time you can get it.
Same way with Photovoltaic, and power towers, and all that.
So, it's a dispatching issue. So, I claim that, you can argue strongly
that you going to have to use the, and do use the fossil fuel coal and gas plants,
which is the last ones that you turn on and off, to meet the incremental demand.
In order to meet the increased demand due to the electric cars that need to be
charged. That's, certainly, an, an, a, debatable
position, and I think it's a position that you can defend.
So the conclusion on this, and again I'm going to look, I'm looking at it from the
U.S policy viewpoint, not for an individual situation or an off-grid
situation. But number one, I certainly think that's
it's a little unrealistic to talk about electric cars, have zero emissions, and i
really don't think that statement in general is true, and I think it's at least
some misconception. It's true if you, you, just from the tail
pipe situation. And if you just view it from a isolated
situation where you got solar equipment just serving a car electric car charge it
yourself, but that's a pretty dumb application for solar because it's sitting
there not being used unless you're charging the car.
But anyway. I'll let you debate that.
The CO2 mile per mile then depends on the dispatching issue.
So, if and by the way if you just look at the CO2 emitted from incramentally
cranking up the, the nonrenewable non-nuclear.
Power plants you get about 1.7 pounds of CO2 per kilowatt hour per use.
Not the 1.2 that I used in the example to get 50 miles per hour.
Well when you use the 1.7 assuming that the, the electricities going to come from,
because of dispatch reasons. From the coal and gas power plants.
You come up with about 30 miles per gallon.
So, I believe that there's no black and white answer to this.
And you can change your assumptions and get different answers.
But, I believe that the range of 35 to 50, in my mind, is a pretty.
Good range to look at and consider that the CO2 emissions from electric car, like
the Leaf, getting a third of a, of a kilowatt per mile is will produce.
Now as I said, you can make your own assumptions in the limitations and look at
different scenarios and come up with different answers.
And you can look at where we might be 20 years from now, or 40 years from now, that
I think this applies for those being put on today.
And it helps us to make some decisions about what we need to do with our power.
Plant fleet that is feeding into the grid. If we want to do something about CO2 we
need to deal with this issue. But electric cars are good, by the way,
from the oil savings, so they definitely save oil.
And we need them if for that reason alone. And they certainly don't seem to produce
any more significant CO2 emissions. But I'm not sure how much it'll help us on
the CO2 emissions. You make up your own mind.
I tried to equip you in this course for looking at the facts, and then using the
facts to analyze your questions and come to your own decisions.
So thank you for listening and hopefully that'll generate some more discussion.
Thank you.