Author Topic: ??? What's a common sense viewpoint: Petrol-based charging grid for electric car  (Read 3699 times)

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Offline james_s

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States like California have emission rules for portable generators.

Well, sort of. It isn't like the emission rules on cars though. My Honda generator was purchased in California by the original owner so it has the special California gas cap that has a charcoal filter in it and a mandated lanyard (which I removed because it got in the way) but otherwise it is identical to the 49 state model. Carbureted engine, no EGR, no catalyst, no oxygen sensor, air injection or anything like that. It would never pass the emissions standards cars have to pass.
 

Offline Someone

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Mobile generator, stationary power station, aircraft, etc, they don't have emissions limits anywhere near as restrictive as motor vehicles so comparisons on fuel use are misleading/flakey. Trying to take the fuel use as some measure of environmental impact is then even more incorrect.

That's only because there are not very many of them in spaces where people congregate. If there were millions of 737 jetliners rolling through the streets in every city and town around the country, or if every suburban house had a Diesel generator rumbling away all afternoon next to the driveway you can bet there would be much more restrictive emissions limits than there are. We'd be choking on fumes and smog from them the way people were prior to emissions regulations on cars. It's easy to forget how much cleaner cars are now or even 30 years ago than in the early 70s and before. There are vastly more cars on the road now yet the air is not nearly as polluted from them. Getting rid of the lead in gasoline was probably the biggest environmental improvement in my lifetime, tetra-ethyl lead is really nasty stuff and vast quantities of it were spewed out all over the world resulting in measurable lead contamination virtually everywhere on earth.
Read the full quote:
Quote
But is it green? It’s better than putting diesel in a car, says Edwards, because the constant running rate of the gennie uses the fuel more efficiently than idling and accelerating in a car.
So it uses more fuel in an engine with looser environmental restrictions, and is somehow "greener". No, no it isn't.
A fundamentally wrong conclusion by picking a flawed comparison and failing to actually account for environmental externatilites.

Its neither more efficient or greener.
 
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Offline David Hess

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Quote
But is it green? It’s better than putting diesel in a car, says Edwards, because the constant running rate of the gennie uses the fuel more efficiently than idling and accelerating in a car.

So it uses more fuel in an engine with looser environmental restrictions, and is somehow "greener". No, no it isn't.

A fundamentally wrong conclusion by picking a flawed comparison and failing to actually account for environmental externatilites.

Its neither more efficient or greener.

Usually that is the case though.  Lower compression engines are less efficient but lower compression is required to prevent the formation of excessive nitrogen oxides unless these are handled in some other way.  The flow restriction from a catalytic converter also lowers efficiency.
 

Offline Marco

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Intuitively I'd say being able to easily just throw an order of magnitude more space at catalytic conversion in a stationary generator than in a car will reduce efficiency impact somewhat. Using consumable based approaches is also less of an issue for a generator being run by people paid to run it instead of our lazy asses who don't want to be bothered with an extra pump.
« Last Edit: May 15, 2021, 02:42:19 pm by Marco »
 

Offline Someone

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States like California have emission rules for portable generators.

Well, sort of. It isn't like the emission rules on cars though. My Honda generator was purchased in California by the original owner so it has the special California gas cap that has a charcoal filter in it and a mandated lanyard (which I removed because it got in the way) but otherwise it is identical to the 49 state model. Carbureted engine, no EGR, no catalyst, no oxygen sensor, air injection or anything like that. It would never pass the emissions standards cars have to pass.
There are emissions standards for mobile generators (effectively what that unit was), but a) they aren't required in Australia so its unlikely that was the case for the comparison presented,  and b) the limits are so much higher per unit of energy/work/whatever metric that its implausible the emissions are similar. Going with same year (2019) emissions limits for Europe:

Euro 6 diesel car limits:
CO: 0.5g/km
HC+NOx: 0.17 g/km
Particulate load: 0.0045 g/km
Particulates: 6×10^11 /km

Euro V nonroad mobile machinery diesel engine 8-19kW:
CO: 6.6g/kWh
HC+NOx: 7.5 g/kWh
Particulate load: 0.40 g/kWh
Particulates: n/a

converting that for their idealised 150wh/km in the best case BMW i3:
CO: 1.0 g/km
HC+NOx: 1.1 g/km
Particulate load: 0.06 g/km

So an order of magnitude worse on pollutants, and 2x on CO.

Quote
But is it green? It’s better than putting diesel in a car, says Edwards, because the constant running rate of the gennie uses the fuel more efficiently than idling and accelerating in a car.
So it uses more fuel in an engine with looser environmental restrictions, and is somehow "greener". No, no it isn't.
A fundamentally wrong conclusion by picking a flawed comparison and failing to actually account for environmental externatilites.

Its neither more efficient or greener.
Usually that is the case though.  Lower compression engines are less efficient but lower compression is required to prevent the formation of excessive nitrogen oxides unless these are handled in some other way.  The flow restriction from a catalytic converter also lowers efficiency.
Theoretically, could be possible, but isn't in practice when compared to a car engine which has been pushed to the limits to keep its emissions down (they're trading off all sorts of other parameters to meet the vehicle emissions standards).

Intuitively I'd say being able to easily just throw an order of magnitude more space at catalytic conversion in a stationary generator than in a car will reduce efficiency impact somewhat. Using consumable based approaches is also less of an issue for a generator being run by people paid to run it instead of our lazy asses who don't want to be bothered with an extra pump.
Again, in theory entirely possible. But not done in practice as there is no incentive to do so.

Less efficient use of fuel in a more polluting engine, certainly not greener.

Could possibly perhaps be greener in the future if people wanted to, yes. But thats just hollow promises.
 

Offline G7PSK

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A diesel generator plant runs far more efficiently than a traction diesel and burns cleaner due to only having to run at a fixed speed. There emission regulations for stationary diesel engines presently at tier 4  https://www.wpowerproducts.com/news/generator-tier-ratings/

There are new designs coming to market as well. The Liquid piston engine looks promising at 33% greater efficiency than a conventional ICE unit.  https://www.startengine.com/liquidpiston#:~:text=A%20new%20efficient%2C%20lightweight%2C%20and,all%20internal%20combustion%20engines%20today.

I for one am not writing off ICE engines in any form for the foreseeable future, heavy electric traction is only viable on rails at present, big trucks and agricultural machines will have to have some form of fuel powered engine for a long time yet unless some  invents a battery with a power density equal or greater than that of anything available  to date
 

Offline Someone

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A diesel generator plant runs far more efficiently than a traction diesel and burns cleaner due to only having to run at a fixed speed. There emission regulations for stationary diesel engines presently at tier 4  https://www.wpowerproducts.com/news/generator-tier-ratings/
You make the exact same mistake again, a large stationary engine running at an ideal load could be more fuel efficient, but that is traded off against emissions. Note that the emissions you link to are matching/harmonized with the EU ones I quoted above showing that the limits are extremely lax in comparison to road vehicles. The claim that an electric car powered by a generator is more efficient or green is not true, and has not been shown.

Engines can be optimized towards many different goals, cutting emissions almost universally detracts fuel efficiency. The metrics being discussed here are:
fuel use per distance travelled
pollution per distance travelled

Reducing one does not imply reducing the other, at an engine level they are often competing requirements/metrics. There are larger stationary engines/power plants with tighter emissions that approach the strict limits of "light vehicles", but they achieve lower fuel efficiency.
 
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Offline SilverSolder

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Building on @Someone's comment above,  it is possible to re-tune pretty much any modern ICE car to give better fuel economy and performance... at the cost of emissions.

Basically it works like this:   Performance, fuel economy, emissions...   Choose any two!

 

Online SiliconWizard

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Yep. And with all that said... although the question may at first look interesting, you have to take a look at the bigger picture.

EVs are charged through the electricity grid. Developing a secondary grid just for charging EVs is questionable, and would probably make little sense. I doubt it's going to happen.

So... the overall question is (as always) how we are going to generate that much electricity. We'll just need more power plants. Are some of those plants going to be petrol-based? I seriously doubt it. If we take a look at the current worldwide electricity generation, for fossile fuels, coal is by far the largest. After that we have gas (not gasoline), and oil is a very small amount actually. There's a reason for this.

Again, I highly doubt dedicated grids just for charging EVs are going to happen, and doubt they would make any sense. Because if petrol-based generators are actually more efficient than other means for generating electricity, why wouldn't we use them already? So the point is completely moot IMHO. While the efficiency compared to ICE *may* be slightly better (although, as said above, it's highly questionable), who in here really thinks we're going to invest in large petrol-based generators for a secondary grid and call that "green"? That doesn't quite add up somehow.
 

Offline james_s

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Generators are only going to make sense in specific circumstances. Isolated areas that lack sufficient grid power, and possibly cold climates where the waste heat produced by the engine is not wasted. You can heat your house with engine heat if the engine is stationary, you can't do that engine is in the car.
 

Online tszaboo

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Generators are only going to make sense in specific circumstances. Isolated areas that lack sufficient grid power, and possibly cold climates where the waste heat produced by the engine is not wasted. You can heat your house with engine heat if the engine is stationary, you can't do that engine is in the car.
You are talking about CHP which makes a ton of sense. AFAIK there was a lot of testing of micro CHP generators, but they were more complicated than regular boilers and inverters, so their reliability was worse.
I am a huge advocate of using these technologies combined with Power to gas. Basically using methane as an energy storage and transportation network, instead of electricity directly. Take a petrol station, in the middle of nowhere as an example. Install a large CH4 tank at the back, use micro power plant to generate electricity to charge EVs. Use solar power plant to turn water and CO2 to CH4.
Former username: NANDBlog
 
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Offline G7PSK

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Generators are only going to make sense in specific circumstances. Isolated areas that lack sufficient grid power, and possibly cold climates where the waste heat produced by the engine is not wasted. You can heat your house with engine heat if the engine is stationary, you can't do that engine is in the car.
You are talking about CHP which makes a ton of sense. AFAIK there was a lot of testing of micro CHP generators, but they were more complicated than regular boilers and inverters, so their reliability was worse.
I am a huge advocate of using these technologies combined with Power to gas. Basically using methane as an energy storage and transportation network, instead of electricity directly. Take a petrol station, in the middle of nowhere as an example. Install a large CH4 tank at the back, use micro power plant to generate electricity to charge EVs. Use solar power plant to turn water and CO2 to CH4.
CHP makes a lot of sense instead of the heat pumps the UK government is going to force on every one and as for the UK governments idea of pure hydrogen instead of natural gas down the existing gas network do they not know that most materials are porous to hydrogen, there will be a lot of fires. Many hospital's in the UK already run CHP as do sewage works where the gas is produced on site and then run through the CHP unit.
 

Offline Marco

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There's not enough biogas to make a significant difference, those screwing around in the margin projects should be left to the market. They are just a distraction to government ... which loves spreading around all their money screwing around in the margins.

Make a plan for megaprojects to do 100%, don't worry about 1% projects. Whether it's nuclear plants, pumped hydro, hydrogen in old gas fields ... whatever, if it ain't TWh scale it's not worth worrying their little heads about.
« Last Edit: May 24, 2021, 03:40:06 pm by Marco »
 

Online SiliconWizard

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Generators are only going to make sense in specific circumstances. Isolated areas that lack sufficient grid power, and possibly cold climates where the waste heat produced by the engine is not wasted. You can heat your house with engine heat if the engine is stationary, you can't do that engine is in the car.

Yes of course. Such generators could have their uses. Just realize that authorities do not care about that. They care about distributing energy for the masses. So that doesn't fit in the big picture, and as it concerns a very small fraction of all uses, efficiency for those cases doesn't matter much in the big picture.
 

Online NiHaoMike

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Basically it works like this:   Performance, fuel economy, emissions...   Choose any two!
Logically, the solution then would be to optimize the engine for fuel economy and emissions, then add an electric drivetrain in parallel if more performance is desired.
Cryptocurrency has taught me to love math and at the same time be baffled by it.

Cryptocurrency lesson 0: Altcoins and Bitcoin are not the same thing.
 

Offline SilverSolder

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Basically it works like this:   Performance, fuel economy, emissions...   Choose any two!
Logically, the solution then would be to optimize the engine for fuel economy and emissions, then add an electric drivetrain in parallel if more performance is desired.

There you go, cracked the secret of the Hybrids.
 

Online Kleinstein

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The hybrid or petrol based CHP can be OK for the immediate future, but on the long run there would be no affordable petrol to burn. Depending on how serious they take the climate change - the long run may start in some 10-20 years.
There may still be petrol left, but likely expensive and in limited quantety (by supply or political limits).

There's not enough biogas to make a significant difference, those screwing around in the margin projects should be left to the market. They are just a distraction to government ... which loves spreading around all their money screwing around in the margins.

Make a plan for megaprojects to do 100%, don't worry about 1% projects. Whether it's nuclear plants, pumped hydro, hydrogen in old gas fields ... whatever, if it ain't TWh scale it's not worth worrying their little heads about.
There likely will not be a single solution for all - the conditions are too different.  Especially with the more fluctuating renewables it helps to have a mix from different sources. A single 100% source is very risky and likely not working well, except for a few places with a clear favorite like solar in some desert regions, wind on some islands or high temerature hydrothermal where available.
In the end the current demand is not relevant - the question is what will be available and were. It is easier to more some high energy industries to the source than transporting electricity over long distance.
 
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Offline james_s

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Logically, the solution then would be to optimize the engine for fuel economy and emissions, then add an electric drivetrain in parallel if more performance is desired.

A car fitting that description exists, it's called a Prius. It has a small Atkinson cycle gasoline engine which is optimized for fuel efficiency at the expense of having lousy low end torque and this is coupled with an electric motor-generator which augments the engine to make the car feel reasonably peppy when one wants to accelerate. Various changes and refinements have been made from one generation to another but the same basic idea is the same - highly efficient ICE in tandem with one or more electric motors.
 


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