This analysis is fascinating: it breaks down how when you fill up a petrol car most of the energy never moves it.
-
This analysis is fascinating: it breaks down how when you fill up a petrol car most of the energy never moves it.
Petrol car: 13–21% of the crude oil's energy reaches wheels.
Electric car on today's UK grid: 43–45%.
Electric car on wind+solar: 77–80%.
via Jan Rosenow, Professor of Energy & Climate Policy at University of Oxford
@Natasha_Jay I've heard this described before as "the primary energy fallacy"
-
@mikerspencer @yugthebug @Natasha_Jay Nor sure what you mean by “common scale in the subtitle.”
All of the numbers at the top of each diagram represent percentage losses from the original 100%. Let's say we start with 100 kWh.
Drivetrain losses are the same for both electric vehicles, 20% of whatever's left.
For the “UK grid" car, that's 20% of 45 kWh, or 9 kWh (9% of the original 100 kWh).
For the “wind & solar" car, it's 20% of 79 kWh, or 16 kWh (16% or the original 100 kWh).@MichaelPorter
The subtitle reads "energy flows... on a common scale."I understand the maths and you're explaining it well - thanks! But the figure is still a little confusing that one scenario gets 11% braking returns and the other 19%. Might just have been better to leave that bit off.
-
This analysis is fascinating: it breaks down how when you fill up a petrol car most of the energy never moves it.
Petrol car: 13–21% of the crude oil's energy reaches wheels.
Electric car on today's UK grid: 43–45%.
Electric car on wind+solar: 77–80%.
via Jan Rosenow, Professor of Energy & Climate Policy at University of Oxford
@Natasha_Jay I think this would work a little better if it included the amount of energy. I get what it’s trying to say, that electric vehicles on an electrified grid are the most efficient of the three options here, but I think people could get thrown off by seeing different percentages between the two electric vehicles. Percentages can be tough, but everyone understands loss, and you can compare the total energy expenditure versus kinetic movement at the end.
-
@Natasha_Jay the dodges there are that it doesn't show a hybrid on petrol and that none of the cars seem to have passenger cabin heating, but it's essentially true.
Now if only there were more battery cars that weren't spyware-on-wheels...
@mjr @Natasha_Jay if you posted this on a mobile device the car spyware is redundant anyway.
-
This analysis is fascinating: it breaks down how when you fill up a petrol car most of the energy never moves it.
Petrol car: 13–21% of the crude oil's energy reaches wheels.
Electric car on today's UK grid: 43–45%.
Electric car on wind+solar: 77–80%.
via Jan Rosenow, Professor of Energy & Climate Policy at University of Oxford
@Natasha_Jay as one xkcd says, electric and gas engines both have pros and cons
on the one hand, electric motors are cleaner and more efficient
on the other hand, electric motors are more powerful -
@mjr @Natasha_Jay if you posted this on a mobile device the car spyware is redundant anyway.
@mscheffel @Natasha_Jay no mobile device is with me every car trip, I have the source code to most of my mobile devices & that seems not possible with most cars yet, and I hate the "one thing is broken so we shouldn't care if everything else is broken too" idea.
-
This analysis is fascinating: it breaks down how when you fill up a petrol car most of the energy never moves it.
Petrol car: 13–21% of the crude oil's energy reaches wheels.
Electric car on today's UK grid: 43–45%.
Electric car on wind+solar: 77–80%.
via Jan Rosenow, Professor of Energy & Climate Policy at University of Oxford
@Natasha_Jay by right, there should be a 20% for solar, and whatever is lossed for wind. but i get why those numbers aren't included.
-
This analysis is fascinating: it breaks down how when you fill up a petrol car most of the energy never moves it.
Petrol car: 13–21% of the crude oil's energy reaches wheels.
Electric car on today's UK grid: 43–45%.
Electric car on wind+solar: 77–80%.
via Jan Rosenow, Professor of Energy & Climate Policy at University of Oxford
@Natasha_Jay For wind power it ignores how much wind energy the turbine fails to capture. For solar it ignores how much the panels fail to convert to electricity. In what way is this a fair comparison?
For petrol it fails to account for what could have been gained by separating out the hydrogen atoms and fusing them... but I'll let that one slide for now.
-
This analysis is fascinating: it breaks down how when you fill up a petrol car most of the energy never moves it.
Petrol car: 13–21% of the crude oil's energy reaches wheels.
Electric car on today's UK grid: 43–45%.
Electric car on wind+solar: 77–80%.
via Jan Rosenow, Professor of Energy & Climate Policy at University of Oxford
@Natasha_Jay FWIW, I'm not sure this is a particularly enlightening way to think or describe this issue. Using the abstract amount of theoretically available maximal energy is intuitive in only fairly rare and narrow circumstances, and this framing feels weird to me.
Maybe, describing the inherent conversion efficiency limits from fuel to motion vs electricity to motion would work better? The foundational ratio is still the same, but at least, it'd be close to the abstractions that physicists and engineers actually use in thinking about motor/engine efficiency.
-
It should be noted that the huge drop in petrol cars' efficiency when it reaches the engine and dissipates into heat is NOT going to be improved much upon. There is a fundamental physics limit that prevents it.
@mespique @Natasha_Jay je zajímavé, že u jaderných (atomových) elektráren, se nad tím nikdo nepozastaví...
️
-
This analysis is fascinating: it breaks down how when you fill up a petrol car most of the energy never moves it.
Petrol car: 13–21% of the crude oil's energy reaches wheels.
Electric car on today's UK grid: 43–45%.
Electric car on wind+solar: 77–80%.
via Jan Rosenow, Professor of Energy & Climate Policy at University of Oxford
@Natasha_Jay he's on Fedi: @janrosenow
unfortunately not active anymore, but used to post a lot. Maybe give him a follow to summon him back
-
@Natasha_Jay Also, oil is INCREDIBLY useful for making plastics, fertilizer, chemicals, synthetics, lubricants, and all sorts of other shit that's difficult to replace from natural sources. And then we just go and burn the shit...
I used to maintain a biodiesel plant. Soybeans in, oil products out. Byproducts were USP grade glycerin, lecithin, etc... And it was done at an incredibly massive scale, efficiently.
-
@MichaelPorter
The subtitle reads "energy flows... on a common scale."I understand the maths and you're explaining it well - thanks! But the figure is still a little confusing that one scenario gets 11% braking returns and the other 19%. Might just have been better to leave that bit off.
@mikerspencer @yugthebug @Natasha_Jay Derp, I didn’t even read that. Okay, I see what you’re getting at.
btw The issue we are discussing came up *repeatedly* when I was teaching science - mainly when a lab result was a percentage, *and* the students had to express uncertainty, which often was a percentage also. So we had to be very clear as to whether a result was
(25 ± 4)% or 25% ± 4% (i.e. (25 ± 1)%). -
@Natasha_Jay Then do the same for moving a *person* rather than a *car*, and include an e-bike comparison.
@TimWardCam @Natasha_Jay A person on a bicycle is way worse than an ICE car, due to it taking about ten calories of fossil fuel to farm and transport one calorie of food on average in the West, and human bodies are worse than ICE engines at converting fuel to motive power, between 5 and 10 percent, (we are warm blooded and evolved to generate heat). So we end up about 1% efficient converting fossil fuel to movement, better for vegans or subsistance farmers.
-
@TimWardCam @Natasha_Jay A person on a bicycle is way worse than an ICE car, due to it taking about ten calories of fossil fuel to farm and transport one calorie of food on average in the West, and human bodies are worse than ICE engines at converting fuel to motive power, between 5 and 10 percent, (we are warm blooded and evolved to generate heat). So we end up about 1% efficient converting fossil fuel to movement, better for vegans or subsistance farmers.
@PeteKirkham @Natasha_Jay I have seen an analysis which comes to a different conclusion, though I doubt I'll be able to find it.
-
This analysis is fascinating: it breaks down how when you fill up a petrol car most of the energy never moves it.
Petrol car: 13–21% of the crude oil's energy reaches wheels.
Electric car on today's UK grid: 43–45%.
Electric car on wind+solar: 77–80%.
via Jan Rosenow, Professor of Energy & Climate Policy at University of Oxford
@Natasha_Jay Really makes me wish I had enough solar panels to eliminate the middleman (the national grid) and charge my car directly.
-
@Natasha_Jay the dodges there are that it doesn't show a hybrid on petrol and that none of the cars seem to have passenger cabin heating, but it's essentially true.
Now if only there were more battery cars that weren't spyware-on-wheels...
@mjr @Natasha_Jay I'm so glad my electric car isn't internet connected at all, but I have noticed a LOT of bluetooth and wifi devices in car parks when I'm sat in it waiting in the rain. Why does an electric car need a connection - except to spy on people...
-
@PeteKirkham @Natasha_Jay I have seen an analysis which comes to a different conclusion, though I doubt I'll be able to find it.
@TimWardCam @Natasha_Jay What figure you get rather depends what question you ask - moving a cyclist requires much less power so it still ends up ahead of a car despite being less efficient, and it's not like people don't eat when they don't cycle, so if you just count the extra energy required you'd get a different figure.
-
@TimWardCam @Natasha_Jay What figure you get rather depends what question you ask - moving a cyclist requires much less power so it still ends up ahead of a car despite being less efficient, and it's not like people don't eat when they don't cycle, so if you just count the extra energy required you'd get a different figure.
@PeteKirkham @Natasha_Jay Yes, this is one of those (rare?) cases where you *should* only count the marginal cost.
-
@TimWardCam @Natasha_Jay A person on a bicycle is way worse than an ICE car, due to it taking about ten calories of fossil fuel to farm and transport one calorie of food on average in the West, and human bodies are worse than ICE engines at converting fuel to motive power, between 5 and 10 percent, (we are warm blooded and evolved to generate heat). So we end up about 1% efficient converting fossil fuel to movement, better for vegans or subsistance farmers.
@PeteKirkham @TimWardCam @Natasha_Jay Citation needed, and be sure you use the total calories EROEI for meat, not just the protein EROEI (mammal flesh, half the calories are usually fat). Also don't forget that bicycle calorie burn also provides exercise; what's the MPG of a stationary bike at the gym?
Here's what some asshole with a blog wrote, 15 years ago: https://dr2chase.wordpress.com/2011/01/12/overselling-a-vegetarian-diet-underselling-utility-cycling/
Yes, I own my own personal copy of Food, Energy, and Society, 3rd edition.
