Author Topic: ??? What's a common sense viewpoint: Petrol-based charging grid for electric car  (Read 3980 times)

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Offline RJHayward

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Hi, last night TV host was speculating, saying "even an old-school gas fired generation plant, charging an electric car has got to be more efficient..."

  Plus, then, he added that a typical (gas) combustion engine is only 10 % efficient. I sense that he was using an old, tired trick: quoting mostly correct statements out of full context.??

   I toured a big electricity generation plant, back in school days: the bigger gas turbine systems got something like 85 % efficiency.
  But I still don't buy the whole package, of gas to electric power to batteries, to, finally, an electric motor.
  Certainly, cleaner electric sources may help, and the electric car market looks awesome.
  What's a sensible view, there ?
Thanks.
 

Offline wraper

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ICE is certainly more efficient than 10%. However electric is still way more efficient, even if you burn gasoline at power plant and account for energy transfer and charging losses.
 

Offline RJHayward

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Thanks, wrapper.
I think those answers about overall efficiency appear in various forms in this eevblog forum, but I needed a clear statement.
   Plus, electric car infrastructure helps reduce things like oil changes potentially getting into ground water.
And makes EV panels an attractive replacement, as far as solar panels can take us, today.
  The over-all system we have been using, traditionally also includes the gasoline delivery trucks needed, from local refinery, etc.
(I think maybe I don't trust my TV host(s), anymore (lol)).
 

Offline SilverSolder

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ICE is only efficient under load...  i.e. 60% - 70% of max power is usually where the peak efficiency is found.  A hybrid drive train lets you use a smaller engine that can then operate in this region more of the time - winner.

Consider the implications for a big V8 engine....   :D
 

Offline Someone

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https://www.eevblog.com/forum/renewable-energy/electric-car-experiences/msg2598654/#msg2598654
Energy is energy, cars are being pushed to ever cleaner local emissions (makes sense as they are used in cities near people) which has decreased their efficiency from the achievable peaks. "Efficiency" of large scale power stations depends heavily on their accounting and sinks for the lower value thermal energy.
 
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Online SiliconWizard

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ICE is certainly more efficient than 10%.

Indeed. 30% is a more reasonable average estimate. Of course, in certain use cases, it WILL go down to 10% or even less. Using worst case figures (for the current situation) and best case figures (for the new miracle solution) is a common deceptive practice.

However electric is still way more efficient, even if you burn gasoline at power plant and account for energy transfer and charging losses.

Uh huh. I'd definitely like to see real figures about that, and again not just best cases figures just to make a point. I'm certainly not as optimist. And don't forget to factor in the overall cost of manufacturing and recycling the batteries into the whole analysis.

 
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Offline Ice-Tea

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Doesn't sound reasonable. Electric cars take about 20kWh to run 100km. With power plant efficiencies of 50-60% (and those are state of the art) that takes about 4kg of fuel or so. Running an ICE would take more like 5kg. So, that leaves something like 20 - 25% for transmission and conversion losses and roundtrip battery efficiency. Sounds like a break-even to me. And as you also have to factor in manufacturing and recycling of the battery it looks like a bust to me.
 
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Offline RJHayward

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Thank you, SiliconWizard, Ice-Tea:
  Yeah, first I wanted that statement, clearly made, no 'dancing' around: That's saying things are more efficient, in total, using PETROL fired main generation of electricity, and then charging EV cars.
  I'm thinking, also, there is likely significant loading effects on the electric supply grid, from the massive numbers of cell-phone charging. Although admittedly that's a phenomina of orders of magnitude smaller.
  As for 'trust', in delivery of such overall efficiency, stated; Haha, yeah, uh no (blind) trust, there.
I'm reminded of a childhood trick: you the 'one walkie-talky radio', then your parents are locked-in, forced to buy you that 'second' radio.
   But EV panels have lots of uses, perhaps even when overall resource use is up, often saving on messy cable runs, etc. I have been using my (solar) phone charger, on mini USB. But that's like, 1 1/2 watts.
Oh well... RJ
 

Offline Ice-Tea

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Cell phone charging is peanuts. For reference: you can charge 10 phones with the same power as an old school incandescent light. You can charge 5 000 000 phones or more with the power from a Tesla supercharger.
 
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Online NiHaoMike

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Doesn't sound reasonable. Electric cars take about 20kWh to run 100km. With power plant efficiencies of 50-60% (and those are state of the art) that takes about 4kg of fuel or so. Running an ICE would take more like 5kg. So, that leaves something like 20 - 25% for transmission and conversion losses and roundtrip battery efficiency. Sounds like a break-even to me. And as you also have to factor in manufacturing and recycling of the battery it looks like a bust to me.
https://reneweconomy.com.au/tesla-ev-charged-with-diesel-generator-still-cleaner-than-conventional-car-61942/
The Tesla wins in fuel costs even when compared to a very efficient conventional car, albeit by a thin margin. With a more fair comparison using a conventional car of similar performance (which would likely be far more expensive than a Tesla), there would be a huge difference in efficiency.
I'm thinking, also, there is likely significant loading effects on the electric supply grid, from the massive numbers of cell-phone charging. Although admittedly that's a phenomina of orders of magnitude smaller.
Likely offset many times over by CFL and LED bulbs replacing incandescents. Perhaps EVs can be offset in a similar manner if we encourage the adoption of other energy saving technologies like smart HVAC systems.
Cell phone charging is peanuts. For reference: you can charge 10 phones with the same power as an old school incandescent light. You can charge 5 000 000 phones or more with the power from a Tesla supercharger.
More like 250kW/10W = 25,000.
« Last Edit: April 24, 2021, 07:00:20 pm by NiHaoMike »
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Offline David Hess

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Doesn't sound reasonable. Electric cars take about 20kWh to run 100km. With power plant efficiencies of 50-60% (and those are state of the art) that takes about 4kg of fuel or so. Running an ICE would take more like 5kg. So, that leaves something like 20 - 25% for transmission and conversion losses and roundtrip battery efficiency. Sounds like a break-even to me. And as you also have to factor in manufacturing and recycling of the battery it looks like a bust to me.

The analysis of efficiency is instructive but irrelevant to the owner; what matters is the economics.  I am already hearing complaints from owners of EVs in areas where electricity costs are high making them more expensive than ICE vehicles per mile.

Total cost of ownership is another thing but maintenance costs of ICE vehicles is effectively subsidized by economy of scale and batteries are expensive.
 
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Offline Someone

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Doesn't sound reasonable. Electric cars take about 20kWh to run 100km. With power plant efficiencies of 50-60% (and those are state of the art) that takes about 4kg of fuel or so. Running an ICE would take more like 5kg. So, that leaves something like 20 - 25% for transmission and conversion losses and roundtrip battery efficiency. Sounds like a break-even to me. And as you also have to factor in manufacturing and recycling of the battery it looks like a bust to me.
https://reneweconomy.com.au/tesla-ev-charged-with-diesel-generator-still-cleaner-than-conventional-car-61942/
The Tesla wins in fuel costs even when compared to a very efficient conventional car, albeit by a thin margin. With a more fair comparison using a conventional car of similar performance (which would likely be far more expensive than a Tesla), there would be a huge difference in efficiency.
Yes, we already linked to your pet link and the discussion about why its misleading:
https://www.eevblog.com/forum/renewable-energy/electric-car-experiences/msg2598654/#msg2598654
Energy is energy, cars are being pushed to ever cleaner local emissions (makes sense as they are used in cities near people) which has decreased their efficiency from the achievable peaks. "Efficiency" of large scale power stations depends heavily on their accounting and sinks for the lower value thermal energy.
Much of the electric car world is pushing simultaneous claims of energy efficiency, clean, and low cost. Except they don't all occur at the same time. There are too many abstractions (layers of smoke and mirrors) to make such simplistic comparisons. I'd be guessing most electric cars are polluting more (both over their life, and incremental per km) as the electricity sources used are so poorly regulated in comparison to new ICE vehicles.

Real world electricity emissions:
https://www.epa.gov/energy/greenhouse-gases-equivalencies-calculator-calculations-and-references
700g/kWh, 15kWh per 100km, 100g/km
which is right where efficient ICE cars are, it gets worse if you include other pollutants into the mix as power stations don't control those nearly as tightly as passenger vehicles. Want to buy "green energy"? you can just as easily/cheaply buy "green fuel" with the same dodgy accounting practices applied to pretend like the emissions aren't happening.

Cell phone charging is peanuts. For reference: you can charge 10 phones with the same power as an old school incandescent light. You can charge 5 000 000 phones or more with the power from a Tesla supercharger.
20min, 2 cars each to half capacity, so around 40kWh x 2 cars, which is more like 5,000-10,000 phones filled in the same time. Even if a little exaggerated, still a good way to put it in context:
https://www.withouthotair.com/c19/page_114.shtml
Transport is a huge energy cost of current society, and its not sustainable.
 

Offline RJHayward

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Thanks: David Hess, for your input about high electric bills, for running an EV battery charger (overnight, etc).
My thoughts along the lines of 'available' square footage, of solar panel installation, vs projected volume of EV cars, and of course projected solar plant expansions.
  Say, 40 mile total daily commute, using XXX kw-hours, and, say, 30 million cars (I haven't a clue, what the actual figure is!). What, then, is the projected land use requirement, (and practical constraints thereof)?

   I'm learning the so-called, coffee napkin estimates, in those hilarious videos, exposing 'Solar Roadways' fiasco(s).
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Offline Ice-Tea

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Cell phone charging is peanuts. For reference: you can charge 10 phones with the same power as an old school incandescent light. You can charge 5 000 000 phones or more with the power from a Tesla supercharger.
More like 250kW/10W = 25,000.

Appologies, yes, you're entirely right. Brain fart. Doesn't change the premesis: cell phone charging means nothing.

Offline Ice-Tea

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Thanks: David Hess, for your input about high electric bills, for running an EV battery charger (overnight, etc).
My thoughts along the lines of 'available' square footage, of solar panel installation, vs projected volume of EV cars, and of course projected solar plant expansions.
  Say, 40 mile total daily commute, using XXX kw-hours, and, say, 30 million cars (I haven't a clue, what the actual figure is!). What, then, is the projected land use requirement, (and practical constraints thereof)?

   I'm learning the so-called, coffee napkin estimates, in those hilarious videos, exposing 'Solar Roadways' fiasco(s).
================≠=========================
HUMANS: They've got some great 1950's rock n roll... but maybe seem a bit lost, as they (we) muddle through the other stuff...
==========================

Current energy consumption:



Roughly double that to include EV. Finding the space is not the issue, the fact that its unreliable and unevenly distributed is.
« Last Edit: April 25, 2021, 07:53:43 am by Ice-Tea »
 

Offline tszaboo

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So they are inventing a plug in hybrid, where the ICE part is in a fixed location.
It is kind of ironic, and it shows that the entire EV adaptation is going too fast, and skipping the plug-in step is a mistake.
As I said already before, you can build 10x the amount of cars, if you make plug-in, instead of EVs, or 100x, if you make regular hybrid. Regular hybrid will have 30% better energy consumption than ICE. Plug in could be utilized to some 50-70% better than ICE. Result is much more reduction of CO2 and crap into the atmosphere. But still, all the governments completely forgot about plug-ins, and it shows that they don't care about the environment, its about lobbyism. And they support cars, that an average joe cannot afford, and this continues to be this way, until the battery manufacturing is the bottleneck. And I'm not against EVs, I'm just realistic.
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Offline RJHayward

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...Wait a second: ??  Were you just saying, a customer still keeps the engine part (or ICE), but it is mounted stationary, like behind the garage? So the 'hybrid' car charges up at home, but not on a grid? First thought there is around the gas supply, and hazardous operations, by my old, aging Aunt Bessie...
My imagination straining on this one? Somebody clarify that 'stationary' means, not moving about, with car ??? Hmmm.

   AND, sorry Ice-Tea, did you just say; " yeah, go ahead and (grab) some bunch of square miles of California land?", (For supplying a national / world-wide fleet with no financial worries doing that). Looking at that world wide map... Why the heck use desert land, there? I still bet you can't  just 'GRAB': Most land is, uh,...anyway not to belabour the point.
   Just saying, as Petrol bans linger in the wings...
 

Online NiHaoMike

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...Wait a second: ??  Were you just saying, a customer still keeps the engine part (or ICE), but it is mounted stationary, like behind the garage? So the 'hybrid' car charges up at home, but not on a grid? First thought there is around the gas supply, and hazardous operations, by my old, aging Aunt Bessie...
My imagination straining on this one? Somebody clarify that 'stationary' means, not moving about, with car ??? Hmmm.
That can work very well in cold climates since the heat from the engine would be very useful. Decoupling things a bit, the EV doesn't have to be in the same house and things other than EVs can be powered.
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Online james_s

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Things could get interesting in a cold climate, using a diesel generator and using the cooling water for the diesel to provide hot water and heat for the building. I still don't think it would make sense for most people but there are niche applications where it could work well. I wouldn't bother with gasoline, a diesel is much more efficient, especially when you factor in maintenance. The big advantage you'd get vs putting the engine in the car would be running the engine constantly right at its most efficient point vs in a car where it's all over the place, the efficiency is 0% when the car is idling in traffic and not moving. A big problem though is that this arrangement doesn't give you what is IMO the most compelling advantage EVs offer, that is not having to go get fuel. At least you could have a large stationary tank and have it filled by a delivery service though. Or use a natural gas fired generator so the fuel is piped in.
 
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Offline Ultrapurple

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I have been following this, and similar discussions, with some interest.

Back along I looked into the fuel consumption of one of the popular plug-in hybrids. From what I remember the figure was something like 45 miles per (imperial) gallon overall when using the ICE as required to charge the battery.

My two-ton, ten-year-old, 3 litre V6 diesel gets very similar mileage.

Yes, I know that diesel and petrol are different, but still - this is hardly the massive leap in economy that is being touted as the saviour of the planet.

Here in England electricity generally costs in the region of 20 pence per kWh. On the 20kWh for 100km suggested in an earlier post, that's roughly 3 miles for 1kWh.

One litre of diesel presently costs about 130 pence (most of which is tax). That's the same cost as 6.5kWh, or 20 electric-miles.

At 45.4mpg (imp) (a convenient figure not far off what I get for my car*), that's 10 miles per litre of fuel.

So the all-electric cost per mile is half that of the dieselmobile.

But I mentioned that the fuel cost included taxes. According to the Royal Automobile Club European fuel cost comparison, in the UK that 130p comprises 50p for the fuel and 80p for taxes.

Re-working the fuel cost on a tax-free basis and we suddenly find that 130p buys 2.6 litres of diesel, enough for 26 miles. Suddenly the diesel car is cheaper to run.

Now I do realise that the cost of electricity also includes taxes so I am making a deliberately unfair comparison, but if nothing else it goes to show that one can pick one's variables to suit the argument.

Recently I noticed that home off-grid natural gas-fuelled generators are becoming a thing here. Natural gas costs the equivalent of about 3.5 pence per kWh. Making the big assumption that one could get as much as 33% efficiency pipe-to-plug, on the face of it there seems to be no reason why one shouldn't generate one's own electricity for about 10p per kWh, or half the grid price.

I know I am conveniently ignoring the purchase cost of the generator, maintenance, load factor and suchlike. I just toss this into the mix to ask the question whether a natural gas powered generator would be a cost-effective way to charge your electric car...?


* I get about 42mpg (imperial) overall, or a touch over 50mpg on highway driving. I can get mid-50s if I am careful (=slow) on the highway.


Please don't flame me. With all the diesel, petrol and natural gas in this post, you risk triggering a veritable conflagration.


« Last Edit: April 27, 2021, 02:28:51 pm by Ultrapurple »
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Online james_s

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That's something else that will be interesting as EVs gain popularity. Over here too, a very significant portion of the cost of fuel is road tax, and currently economics greatly favor EVs because there is no road tax on electricity, and you can't dye electricity to make it possible to detect untaxed electricity in the battery. Right now EVs have very favorable economics, but if too many people get them then the state will have to find some other way of taxing drivers to pay for road maintenance and there is some concern that increased demand will drive up the cost of electricity. I'm a proponent of EVs overall, but I don't want everyone to get them, one of the big advantages is spreading out the needs of society over multiple different fuel sources. Having a mix of vehicles burning gasoline, diesel, propane, CNG, and some using electricity gives us the advantage of diversity.
 

Online NiHaoMike

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Right now EVs have very favorable economics, but if too many people get them then the state will have to find some other way of taxing drivers to pay for road maintenance
That has been invented a long time ago - toll roads.
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Online james_s

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That has been invented a long time ago - toll roads.

We don't really have those here and never really have, with the exception of a few bridges. It would be political suicide to implement it, and then what about all the people with fuel powered cars who already pay a gas tax?
 

Offline Someone

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So the all-electric cost per mile is half that of the dieselmobile.

But I mentioned that the fuel cost included taxes. According to the Royal Automobile Club European fuel cost comparison, in the UK that 130p comprises 50p for the fuel and 80p for taxes.
Most developed/western countries fall somewhere around that same 1/2-3/4 "cost" for the marginal price of energy the consumer sees. If taxation were equal for all road going energy sources then electricity ends up more expensive in most places!

Right now EVs have very favorable economics, but if too many people get them then the state will have to find some other way of taxing drivers to pay for road maintenance
That has been invented a long time ago - toll roads.
We don't really have those here and never really have, with the exception of a few bridges. It would be political suicide to implement it, and then what about all the people with fuel powered cars who already pay a gas tax?
The front running scheme is distance based pricing:
https://en.wikipedia.org/wiki/Vehicle_miles_traveled_tax
Which can be applied to all vehicles and replace the fuel excise. Weight/risk/environmental incentives are possible to capture quite easily. Such a scheme has different characteristics to a fuel tax so some people would be better off, some others worse off. Politics is generally shy about major changes, so it'll be interesting to see what solution is finally implemented.
 

Online james_s

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https://en.wikipedia.org/wiki/Vehicle_miles_traveled_tax
Which can be applied to all vehicles and replace the fuel excise. Weight/risk/environmental incentives are possible to capture quite easily. Such a scheme has different characteristics to a fuel tax so some people would be better off, some others worse off. Politics is generally shy about major changes, so it'll be interesting to see what solution is finally implemented.

Seems like that would be really difficult to implement. None of my cars are new enough to have OBDII so there's nowhere to plug in a device that would interface to the car directly, and anything else I could easily leave at home or switch off. I don't see how they're going to come up with something that people won't easily game.
 


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