This analysis is fascinating: it breaks down how when you fill up a petrol car most of the energy never moves it.
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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.
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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.
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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...
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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
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@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.
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@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.
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@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.
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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.
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@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...
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@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.
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@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.
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@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.
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@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.
@donburi @Natasha_Jay but why would you want those numbers? It's like counting all the water your bucket didn't pick up by the river. It's meaningless in this context. Unlike the energy from the oil
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@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.
@dr2chase @TimWardCam @Natasha_Jay So with your blog's figures varying between 20:1 for meat and 1:1.3 for potatoes, so 10:1 for a mixed diet seems about right, then the 10% efficiency figure I remembered seems low compared to 24% quoted in wikipedia (https://en.wikipedia.org/wiki/Human_power#cite_note-2) , but their figure is just for one muscle rather than a whole human. So increase it to 2.4% if you want. The reasons for choosing cycling are not its efficiency, but many other benefits.
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@dr2chase @TimWardCam @Natasha_Jay So with your blog's figures varying between 20:1 for meat and 1:1.3 for potatoes, so 10:1 for a mixed diet seems about right, then the 10% efficiency figure I remembered seems low compared to 24% quoted in wikipedia (https://en.wikipedia.org/wiki/Human_power#cite_note-2) , but their figure is just for one muscle rather than a whole human. So increase it to 2.4% if you want. The reasons for choosing cycling are not its efficiency, but many other benefits.
@PeteKirkham @TimWardCam @Natasha_Jay there's a bunch of problems with your estimate -- not all meat is beef, all meat is only about 17% of US diet by calories (per quick web search), and marginal calorie consumption from exercise burn is not necessarily like the average, and more so the further you depart from sedentary.
And you completely missed that the calories can be charged to either exercise or transportation. If I spend 3000 calories/week on exercise, transportation is *ZERO*.
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@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 @PeteKirkham @Natasha_Jay Apparently it’s heavily dependent on what you eat to make up for the extra calories you burn - ranging from 25 gCO2e/km for bananas (about half the rate of an EV) to 310 gCO2e/km for cheeseburgers (about double that of a petrol car)! Ref: Mike Berners-Lee via https://ourworldindata.org/travel-carbon-footprint
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@Natasha_Jay I call nonsense. The car isn’t determined by power source so why is a (for eg) Tesla powered by solar going to be getting more power to the wheels than “standard”electricity? Also why is transmission more expensive in one than the other? Is there some underlying assumption that solar is a home generated source? In which case it’s unlikely to fully power the car unless you have a very large array for a house.
The wheels don't get more power. But the percentage of power they get from the original source is greater.
In transmission, the losses are greater for wind & solar, which makes sense makes usually the locations for wind & solar are farther away then that for traditional power plants.
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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 “There is nothing better than a petrol car” (German car industry)
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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 this is really interesting, but it feels a bit oversimplified and possibly, but hopefully not aimed at driving a predetermined conclusion for the following reasons:
1. As others have pointed out, crude is fractured into many products, not just Petrol.
2. There doesn't appear to be any acknowledgment for the efficiency of the battery which for Lithium Ion I believe is at best 90%
3. The extra weight of the batteries isn't represented at all, but the petrol heat is???
