MPG Hacks, Please?

Except fuel economy is not a measure of emissions, its a proxy for estimating emissions, even if you think a 1998 car that gets 26 MPG releases the same emissions per mile as a 2017 car that gets 26 MPG.

You’re trying to use input as a measure of output. Ask a factory manager why that doesn’t work.

Regarding China’s use of fossil fuels, I offer the following:

“China is aiming to peak its coal consumption by 2020 and is attempting to limit the growth of its oil consumption. It intends to grow its share of natural gas, nuclear, hydro and other renewables. Also, energy efficiency gains must be realized across all sectors of the economy. In reality, dozens of policies must be successfully adopted and implemented for China to increase the share of non-fossil fuels in primary energy consumption to around 20 percent.”*

*China’s Contribution to the Paris Climate Agreement

Three Reasons to Believe in China’s Renewable Energy Boom

China Aims to Spend at Least $360 Billion on Renewable Energy by 2020

In terms of CO2 emissions (as I said) both cars are identical. Not true for all other emissions, which I also addressed. I’m concentrating on CO2 because that’s what seems to be driving (sorry) the push for EVs.

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Not when you’re comparing them to power plant emissions.
To do a fair comparison would require a comparison of how many of each unwanted emission is produced by a large number of gas-powered cars for a significant number of miles (say a million cars for 10,000 miles each) and the unwanted emissions produced to operate the same number of EVs for that number of miles… after subtracting the emissions generated by the power plant for powering things other than cars, like homes and factories.

I’m unaware of any such study. If you are, I’d love to read it.

I don’t understand. Why is it not the CO2 from burning the gasoline compared to the CO2 from burning the coal, each to move a vehicle an equal number of miles?

Because:

  1. Coal and gasoline do not produce the same amount of CO2 per joule of energy. Gasoline also produces water, which is not a pollutant.

  2. Coal plants produce many other pollutants. Did you know that coal plants produce about twice the radioactive emissions than an equivalent nuclear plant. Plus heavy metal (cadmium, mercury, lead) by the megaton, plus others.

  3. The power plant has a high efficiency, approaching 60%, whereas an automobile is at 30% typically.

  4. There is a loss transmitting the power from the plant to the charging station, perhaps 10% or so.

  5. and much more…

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Talking about CO2 only, the analysis I posted (the map) shows the mpg a car would need to get to emit the same CO2 as the power plant generating the electricity needed to travel the same distance. Got it?

That’s a problem.
You can’t fairly compare the environmental impact of gas operated engines with that of EVs by only comparing their CO2 emissions with that of power plants.

I’m not an environmentalist. But there’s absolutely no data suggesting that EV automobiles will produce more unwanted emissions than gas-powered cars. None. Statements implying that need to be backed by some form of scientific data before I’ll accept them.

Inferring from MPG comparisons is very bad science, especially if it’s applied to the United States, which has a grid of multiple different generation technologies and environmental mandates China doesn’t have. The article talking about China’s smog concerns include in the emissions generated by coal fired plants to power all the other users of electricity in them, and talks only to smog-generating particulate matter and not to CO2, NOx, or hydrocarbons.

In short, data showing that EVs will be more damaging to the environment than gas-powered cars simply doesn’t exist. Or, if it does, I still haven’t seen it.

Lots of environmental problems with Li-ion battery production, as shown in several studies. Here’s a quote: “The study showed that current production methods of EVs are significantly more environmentally damaging than the production of ICEVs.”
http://berc.berkeley.edu/is-the-electric-car-really-helping-the-environment/
Look, I have no problem with somebody buying an EV. I got a hybrid. But major government subsidies, either direct $7,500 federal plus lots of state $$, or CAFE ‘counts as zero pollution, infinite mpgs’ treatment, is a major waste of our $$.

I don’t think local air pollution is coming from brand new cars. It’s much more a case clunkers (which can be surprisingly new) emitting 10 to 100X the amount they should be.

This talks about a variety of issues:

Here’s one more:
https://www.ft.com/content/8342ec6c-5fde-11e7-91a7-502f7ee26895

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Those are great links.

While I like the idea of EVs, I’m undecided on the environmental benefits. The technology is very new, very much in its nascent development stages. I’m optimistic that better energy cells will be developed that will drastically change the variables. NOVA had a great special on PBS entitled “The Search For The Perfect Battery” that researched the issue in depth. There’re some great advances still under development, including a true lithium battery (rather than lithium-ion) that look like they’ll be not only safe (can’t develop dendrites) but easier to produce and much more energy-dense. If you see the NOVA special coming to your area, I recommend watching it. Regardless which side of the puzzle you support, it’s a great NOVA.

I think we’re in the “Model T” stages of EVs. I have high hopes for the future.
I would also expect this technology to drive battery development and the benefits to bleed over into other industries. Just as PCs drove the development lithium-ion batteries, I’d expect their introduction into the automotive arena to bleed into other areas… including the evolution of the batteries themselves.

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I think there are 2 advantages electric vehicles have over IC vehicles.

  1. They move the pollution part to another location. In a city, that could be a very valuable thing.

  2. They collect all that pollution generation is a single location making it easier to deal with.

I tend to regard the 1901 Baker Electric as the “Model T” of EVs.

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I’d add number 3:

  1. less pollution overall.

In the US, electric production is 39% coal, 27% natural gas, 20% nuclear, 13% renewable. World wide, the numbers are something like 70% fossil fuel, 30% nuclear, renewable, hydro. (Source Wikipedia)

All but the coal is definitely less polluting than an IC engine. And a modern coal plant runs to about 40% efficiency. The IC engine is 30% at best. However, that doesn’t account for all radioactive and heavy metal pollutants the coal plants discharge (which may be captured in a modern plant).

But given the mixture of power production, the net pollution of an EV is (my guess, it’s a difficult calculation) perhaps half that of an IC engine.

That’s no longer true. The Prius IC engine is at 40%:

You often hear the argument that the first Model T’s were also very crude when some new engine or automotive power source is developed. This misses one really important point. The inventors of the Wankel rotary engine did not have to re-invent the spark plug, carburetor, ignition coil, distributor, and the transmission when they developed this engine.

The evolution of high density power cells and the work Tesla has done in making large arrays viable have made EVs possible for the masses, just as the Model T did with gas-powered automobiles. As cool as the Baker was, they never accomplished what the Model T did. I believe the Model T is a far better analogy to the modern EV than the Baker.

But the average is much lower. Specially when you consider all the 10 year old mistuned cars around.

But there are inefficiencies all the way from the generation to the road. You have line loss, you have inefficiencies from converting AC to DC, and you have inefficiencies in the electric motors as well.

true. That’s why it’s a really complicated calculation.

Not really so complicated.

Generally, with a 50% efficient power plant, 93% transmission efficiency, 85% charger eff, 90% battery charge and discharge efficiency, 90% DC/AC invertor efficiency, 96% motor efficiency and 97% powertrain efficiency,

0.50 x 0.93 x 0.85 x x 0.90 x 0.90 x 0.96 x 0.97 = 0.298

So the total power plant to wheels efficiency is 30% Better than about 15% or so for IC, but still, lots less than people tout.

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