Author Topic: EV Physics question  (Read 4567 times)

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Offline veedub565

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EV Physics question
« on: October 01, 2022, 07:46:07 pm »
This may be a bit OT but.. Carbon emissions from ICE cars is contributing to global warming, and at some point we're going to run out of dead dinosaur juice. On the face of it EV's are cleaner and more sustainable long term, here's a question though.

You don't get something for nothing, you usually end up having to pay for it somewhere along the line. From start to finish, ICE compared to EV, wouldn't the total energy expended and environmental impact just wind up being the same ?  different ways, but, the same, like in an ashes to ashes dust to dust kind of way.

I'm not having a bash on either format, I'm just curious.

I guess what I'm wondering is, aren't we just going to end up paying for EV's, just the same as we are with ICE, but in a new and different way.
 

Offline Faringdon

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Re: EV Physics question
« Reply #1 on: October 01, 2022, 09:43:21 pm »
EVs  will be better when we finally allow windfarms on every street corner, and solarpanels everywhere.
...And our government finds a way of getting huge battery storage stations on the national grid.
Then EVs will literally be driving on sunshine and wind.
But fossil fuel gaffers earn big bucks at the mo, and are thus very powerful...so we may have to wait for our revolution.

Also, fossil fuels are the fuel of war (rocket missiles need them, such missiles cant run on battery).....so countries like having all the fossil fuel infrastructure..because it allows them to be war ready...so keeping fossil fuels seems to make sense, kind of.
« Last Edit: October 01, 2022, 09:49:43 pm by Faringdon »
 

Online TimFox

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Re: EV Physics question
« Reply #2 on: October 01, 2022, 10:03:51 pm »
The effect of fossil-fuel burning ICEs is not only the heat emission (waste heat from combustion) over and above the energy required to achieve motion, but the chemical emissions (CO2, NOx, etc.)
The waste heat from good electrical motors is far less than the unavoidable waste heat from heat engines.
The chemical emission problem for EVs depends on how the electrical power is generated, from "clean" (solar, wind, nuclear, hydro) through "not-so-bad" (natural gas), through "filthy" (coal).
 

Offline ejeffrey

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Re: EV Physics question
« Reply #3 on: October 01, 2022, 10:21:56 pm »
You don't get something for nothing, you usually end up having to pay for it somewhere along the line. From start to finish, ICE compared to EV, wouldn't the total energy expended and environmental impact just wind up being the same ?  different ways, but, the same, like in an ashes to ashes dust to dust kind of way.

No, it turns out that Karma is not a law of physics.  ICEs and EVs both have environmental costs of course and the exact impact depends on a lot of factors, but there is no "rule" that they have to be equal or similar in any way.  I can't even imagine how someone could think that.
 

Offline sleemanj

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Re: EV Physics question
« Reply #4 on: October 02, 2022, 12:38:34 am »
From start to finish, ICE compared to EV, wouldn't the total energy expended and environmental impact just wind up being the same ? 

No, why would you think that, I don't understad your reasoning.  They are two fundamentally different technologies.

Like saying "what difference does it make if I eat lettuce, or lasagne, both are food so must be the same!"

To produce and use ICE fuel, you have to extract it from the earth, put it through expensive refining processes, put in additives and so forth, deal with the waste products, ship the fuel around in big ships which themselves burn even dirtier fuel distribute it to retail locations in tanker trucks, fill up vehicles, and burn it producing various rather unpleasant emissions.

To produce and use EV fuel, you have to harvest energy much of which is available in on human scales infinite and clean forms, the main one of which being literally light from a star, feed it through wires, plug in your vehicle to charge some batteries, and convert it into kinetic energy and eventually to heat.

Yes I didn't account for manufacturing of the battery and power stations... or the car, refineries, drilling rigs, ships, emissions control, climate impact, loss of food producing land to biofuels...

This "it's all the same" is a classic, and ridiculous trope of the anti-ev-at-any-cost crowd, "but but but where does your electricity come!" or "but but but making batteries has evironmental impact!" or "but but but what are you going to do when the batteries are worn out!".

It is complete nonsense.




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Offline james_s

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Re: EV Physics question
« Reply #5 on: October 02, 2022, 01:19:40 am »
It's hard to get really concrete data on this but from the bits and pieces I've found the consensus seems to be that EVs are environmentally marginally less harmful to the planet than ICE powered cars, the benefits often greatly exaggerated by one group while the flaws are greatly exaggerated by another group. If you're planning on replacing a car anyway it could make more sense to go electric than if you already have a perfectly usable car that you could keep going for some time by doing some work on it rather than scrapping it prematurely.
 

Offline sokoloff

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Re: EV Physics question
« Reply #6 on: October 02, 2022, 02:04:18 am »
Also, fossil fuels are the fuel of war (rocket missiles need them, such missiles cant run on battery).....so countries like having all the fossil fuel infrastructure..because it allows them to be war ready...so keeping fossil fuels seems to make sense, kind of.
I’d expect most missiles to use a solid propellant and very few to use fossil fuels. Some drones may use fossil fuels as do the manned aircraft which carry the missiles.
 
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Online bdunham7

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Re: EV Physics question
« Reply #7 on: October 02, 2022, 02:39:25 am »
"but but but where does your electricity come!" or "but but but making batteries has evironmental impact!" or "but but but what are you going to do when the batteries are worn out!".

It is complete nonsense.

Those are all legitimate questions.  They may have answers, but they aren't just FUD. 

My incremental rate for charging (at night) has gone from $0.13/kWh to $0.31/kWh due to rate increases and changes.  And we in California were all recently advised not to charge during a recent power usage event--that's not a big deal right now, but with much higher EV adoption rates it will be.

I don't know about lithium mining issues in Australia, but in South America it has been a bit more than messy IIRC.  Big deal?  I don't know, but worth discussing.

My EV recently had a battery issue  (coolant leak) that was resolved by replacing the battery packs.  It was under warranty.  Out of warranty--and the warranty ends this month--that repair would have been so expensive that the car would have been scrapped if I couldn't manage an alternative repair.  Both of my other (ICE) cars are older than the EV and not in danger of being scrapped due to needing a repair.  Well at least one isn't.  The other is 20 years and 200K miles (320k km) old, so if the transmission dropped its gears on the road it might be done.

So, not FUD.  Legitimate issues.
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Offline sleemanj

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Re: EV Physics question
« Reply #8 on: October 02, 2022, 04:31:44 am »
"but but but where does your electricity come!" or "but but but making batteries has evironmental impact!" or "but but but what are you going to do when the batteries are worn out!".

It is complete nonsense.

Those are all legitimate questions.  They may have answers, but they aren't just FUD. 

  1. Electrical energy comes from different sources, many of which are clean, some of which are not, the ones that are not are easier to make cleaner than a million petrol cars and every time you replace a dirty station with a clean one all the EV suddenly get a little cleaner.  If there is not enough capacity more power stations can be built, power stations are money printers, businesses will want to build power stations (and charging points).

  2. Everything has an environmental impact, we manage these, it is easier to manage the environmental impact of battery building in a few locations than it is to manage the environmental impact of hundreds of millions of ICE vehicles. Lithium can be harvested in theory from seawater where there is an abundant supply, it's just not practical to get it yet.  As battery technology evolves we may reduce our dependance on mined resources, it is the best we have so far, do not let perfect be the enemy of better.

 3. On the whole EV battery technology has progressed to the point where batteries last the vehicle life.  Batteries can be recycled, it is actually a problem developing that there are [not enough batteries to recycle](https://www.stuff.co.nz/motoring/300679175/the-next-big-battery-material-squeeze-is-old-batteries?dicbo=v2-8bf65ad5a1e9372e50d5d634380ce6760) for the number of recycling plants coming online.  Batteries can also be reused for alternative usage situations which do not require the same energy density (storage).  Batteries have valuable materials in them, people like to get valuable materials from waste, because, money.

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Offline veedub565

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Re: EV Physics question
« Reply #9 on: October 02, 2022, 07:20:51 am »
What I'm trying to understand is you don't get something for nothing, nobody has invented perpetual motion yet.

In terms of energy and resources The total 'cost" of propelling 2 ton of metal at 50mph should be the same, right ?  Regardless of what source of power you use.


Why would you think I'm anti EV. Make it about Diesel and steam powered locomotives if you like.

 

Offline veedub565

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Re: EV Physics question
« Reply #10 on: October 02, 2022, 07:34:02 am »
This is what I mean (attached)

Whatever the power source, Diesel, Electric, Steam... Cabbages. In some areas you pay more, in other areas you pay less, but in total it should all end up the same ?
 

Offline Ice-Tea

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Re: EV Physics question
« Reply #11 on: October 02, 2022, 07:52:33 am »

Offline Nusa

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Re: EV Physics question
« Reply #12 on: October 02, 2022, 07:59:04 am »
Engines have different efficiencies, depending on the technology used and the size and duty cycles involved.

The battery-motor conversion in the modern EV is more like 75% efficient. Yes, the energy to charge the battery came from somewhere, but likely a more efficient source than ICE engines. Additionally, EV's can reclaim a great deal of energy by using the battery-motor system for braking. This is why you see better performance figures for EV's in city driving vs highway driving.

Your average ICE engine in a modern car is going to be in the 30-40% range, meaning 60-70% of the energy is being discarded as heat. When it comes to stopping, ALL of the energy is wasted as heat by the brakes.

That's just barely touching on the differences, but should be more than enough to prove the point that they ARE different.


 
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Offline redkitedesign

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Re: EV Physics question
« Reply #13 on: October 02, 2022, 08:08:29 am »
Whatever the power source, Diesel, Electric, Steam... Cabbages. In some areas you pay more, in other areas you pay less, but in total it should all end up the same ?

No, it shouldn't.
There is no advantage of steam over Diesel (for vehicular propulsion that is, for Nuclear power generation steam is better than Diesel).
There is no reason to assume that Electric has drawbacks that make it at least as bad as ICE.

There is no Conservation of Karma law.
 
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Offline veedub565

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Re: EV Physics question
« Reply #14 on: October 02, 2022, 08:20:44 am »
Yes I think I can see a flaw in what I was thinking. Diesel, Steam, Electric, Nuclear.. whatever the power source for your vehicle, it would have it's own total energy life cycle. And that doesn't have to be all part of the same cycle. I mean the "operation" part of the cycle is the same, propelling 2 tons of metal at 50mph for example.

Yes conservation of energy law is what I was thinking of I think.


There's no question an EV charged up with renewable energy is a cleaner alternative to fossil fuels, and nuclear really as you have no contaminated waste to get rid of. Just part of my mind thinking... but there must be a cost to it somewhere equal to the other forms of propulsion
« Last Edit: October 02, 2022, 08:24:14 am by veedub565 »
 

Offline sleemanj

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Re: EV Physics question
« Reply #15 on: October 02, 2022, 08:57:54 am »
Where you have gone wrong is to not take into account losses in the system.

The energy required to move a vehicle is more than just the energy to move the wheels, it's that's plus all the lost energy that gets just thrown away as heat to the universe before it gets to those wheels.

We can start with the direct losses at the vehicle, a lot of the energy that goes in, comes out not as kinetic energy you want, but also heat which is mostly discarded.  ICE makes lots of discarded heat energy.  EV makes a lot less of that wasted energy.

Or we could look to losses in the supply chain.  In ICE fuels, we have to transport it to the appropriate places right, that transport involves vehicles, the fuel to power those vehicles doesn't come from the aether, it's a loss.  For electric, the energy required to get electricity from generation to your vehicle are probably rather smaller (but I'm not going to calculate).

And we can continue going back up that trail, generation and refining, harvesting and extraction...

You can't just look at "it takes X joules to move the wheels" and say everything is the same, because it actually takes "X joules, plus all the joules we needed along the way but never got to the wheels".

To go back to my lettuce and lasagne, yes you can get energy from eating lettuce, and you can get energy from eating lasagne, but you have to invest a lot more eating time into getting the same amount of energy from the lettuce as from one hearty spoonful of lasagne.
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Offline mikeselectricstuff

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Re: EV Physics question
« Reply #16 on: October 02, 2022, 10:51:46 am »

My EV recently had a battery issue  (coolant leak) that was resolved by replacing the battery packs.  It was under warranty.  Out of warranty--and the warranty ends this month--that repair would have been so expensive that the car would have been scrapped if I couldn't manage an alternative repair. 
But for something like a coolant leak, an alternative repair would almost certainly have been possible. ( see recent Rich Rebuilds video on exactly this).
And even if not, the battery cells would have significant value for reuse, and eventually recycling to recover materials for new batteries.
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Online CatalinaWOW

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Re: EV Physics question
« Reply #17 on: October 02, 2022, 12:14:53 pm »
I am disappointed that in a technical forum like this so many of the answers are hand waving and emotional.  The OPs question is valid.  The fundamental energy consumption of moving the vehicles is the same. 

There is no reason to assume that the efficiency of converting the source energy to motive power is the same, nor that the environmental impact is the same.  Which is better is a far more difficult question, and one that is not fully answerable now.  There is reason to be optimistic that the EV path is better, but much is actually unknown.  For example - Are there significant environmental effects from extracting energy from the wind?  Questions like this are frequently raised as FUD tactics, but no FUD tactic is successful unless there is some potentially real issue.

My response is nearly as hand wavy as many of the above.  It is because a real answer to the question is very difficult to come by, and will probably only be found by experience.  Just as we learned the problems of fluorocarbon refrigerants when we used them on an industrial scale.

I believe that electric is the better answer, but am humble enough to say I don't know and jaded enough to say that I don't think anyone does.
 

Offline redkitedesign

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Re: EV Physics question
« Reply #18 on: October 02, 2022, 02:06:38 pm »
Which is better is a far more difficult question, and one that is not fully answerable now.  There is reason to be optimistic that the EV path is better, but much is actually unknown.  For example - Are there significant environmental effects from extracting energy from the wind?  Questions like this are frequently raised as FUD tactics, but no FUD tactic is successful unless there is some potentially real issue.

There is no development ever where the full effect can be known in advance, by definition. However, if would have been an argument in the past, we would never have had weels, let alone ICE. However, if we would have started with converting to sustainable once the side effects of fossil fuels were reasonably sure, we would all have had an electric plane in 1999 (okay, the plane part might be an exaggeration)

Handwaving and concerns are nice, but given 2 options, were option A is almost certainly bad, and option B might have unforseen consequences only a fool would argue that those uncertainties should be a reason to stick with A.
 

Online bdunham7

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Re: EV Physics question
« Reply #19 on: October 02, 2022, 02:13:41 pm »
1. If there is not enough capacity more power stations can be built, power stations are money printers, businesses will want to build power stations (and charging points).

2. Lithium can be harvested in theory from seawater where there is an abundant supply, it's just not practical to get it yet.

3. On the whole EV battery technology has progressed to the point where batteries last the vehicle life.

OK, so you wave your hand three times and the problems disappear!

1.  If that is true why is electricity getting so expensive in some areas?  Perhaps even if there were adequate power plants, we'd still need fuel for them and perhaps expanded distribution networks?  Not trivial issues IMHO.

2.  "not yet..."   LOL.  Perhaps both 1 and 2 will be solved with the imminent introduction of commercial nuclear fusion plants.  Oh, wait....

3.  Mine didn't and I'm not alone.

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Online bdunham7

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Re: EV Physics question
« Reply #20 on: October 02, 2022, 02:25:55 pm »
Handwaving and concerns are nice, but given 2 options, were option A is almost certainly bad, and option B might have unforseen consequences only a fool would argue that those uncertainties should be a reason to stick with A.

Why not let B naturally progress instead of 'we' deciding to go all-in on only one option? 

And just to give a stark example, Germany decided to 'push' green and clean energy by simply shutting down their coal and nuclear power, thus forcing the adoption of solar....and nice, clean Russian gas.  A 'fool' (the one and only Donald Trump) argued against this and was ridiculed for it.  Now of course they are regretting this and looking to put off the nuclear plant shutdowns that haven't happened yet.  I don't know if they can practically recommission any of the coal plants that have gone offline.
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Online CatalinaWOW

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Re: EV Physics question
« Reply #21 on: October 02, 2022, 04:07:44 pm »
Which is better is a far more difficult question, and one that is not fully answerable now.  There is reason to be optimistic that the EV path is better, but much is actually unknown.  For example - Are there significant environmental effects from extracting energy from the wind?  Questions like this are frequently raised as FUD tactics, but no FUD tactic is successful unless there is some potentially real issue.

There is no development ever where the full effect can be known in advance, by definition. However, if would have been an argument in the past, we would never have had weels, let alone ICE. However, if we would have started with converting to sustainable once the side effects of fossil fuels were reasonably sure, we would all have had an electric plane in 1999 (okay, the plane part might be an exaggeration)

Handwaving and concerns are nice, but given 2 options, were option A is almost certainly bad, and option B might have unforseen consequences only a fool would argue that those uncertainties should be a reason to stick with A.

Your argument could be used to explain why we should never develop electric cars (or planes).  Because personal automobiles are really a bad solution from a variety of perspectives.  We should eliminate single family dwellings, build arcologies and use only trains for long distance transport.  Yeah, there is massive capital investment in making that change, but think how wonderful it would be.

 

Offline Faringdon

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Re: EV Physics question
« Reply #22 on: October 02, 2022, 05:43:28 pm »
We can easily get totally independent of fossil fuels.......its just the power-struggling and rat-racing thats going on that stops it....
Here is a German town that is self sufficient in  energy...all from green sources.....
Everywhere could be like this if we had battery storage all over the place....which is easily possible, Australia already does it.....MooraBool



In UK recently, a farmer was killed and his death faked as suicide...all because he had a wind turbine erected on his own land...
https://www.telegraph.co.uk/news/uknews/1552390/Farmer-kills-himself-after-opposition-to-wind-turbines-on-his-land.html
« Last Edit: October 02, 2022, 05:46:01 pm by Faringdon »
 

Offline james_s

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Re: EV Physics question
« Reply #23 on: October 02, 2022, 06:16:35 pm »
Your argument could be used to explain why we should never develop electric cars (or planes).  Because personal automobiles are really a bad solution from a variety of perspectives.  We should eliminate single family dwellings, build arcologies and use only trains for long distance transport.  Yeah, there is massive capital investment in making that change, but think how wonderful it would be.

That sounds like hell to me. I think I would rather be dead than imprisoned in an apartment in crowded urban city. A single family home on some land is the only arrangement I find tolerable. As it stands I can hardly wait for the day I can retire and move somewhere rural with more open space around me and fewer people clogging the roads. I have to go into downtown Seattle sometimes for work and I absolutely hate it there.
 

Offline coppice

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Re: EV Physics question
« Reply #24 on: October 02, 2022, 06:24:20 pm »
Your argument could be used to explain why we should never develop electric cars (or planes).  Because personal automobiles are really a bad solution from a variety of perspectives.  We should eliminate single family dwellings, build arcologies and use only trains for long distance transport.  Yeah, there is massive capital investment in making that change, but think how wonderful it would be.
Have you considered a career as a scriptwriter for dystopian movies?
 
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