Post by: charli on 31/05/2021 09:22:19
"Hypothetically speaking, if all modes of transport were electric, would this cause greater pollution (in terms of output from power stations) than conventional petrol or diesel modes of transport?"
Post by: Zer0 on 31/05/2021 10:03:24
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Very Interesting Question, i must Admit.
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Anyways, I'd think of this in terms of
" Efficiency " !
(Fuel consumed to power generated ratio)
1) How Efficient are Power Plants?
" (Typical thermal efficiency for utility-scale electrical generators is around 37% for coal and oil-fired plants, and 56 – 60% (LEV) for combined-cycle gas-fired plants. Plants designed to achieve peak efficiency while operating at capacity will be less efficient when operating off-design (i.e. temperatures too low.) "
Source - Wikipedia.
2) How Efficient are Electric cars?
" (Efficiency. EVs convert over 59-62% of grid energy to the wheels. Conventional gasoline vehicles convert only some 17%–21%.
Plug-in hybrid vehicle: Less use of petroleum, residual use of electricity
Regular hybrid electric vehicle: Less use of petroleum, but unable to be plugged in.) "
Source - Wikipedia.
3) How Efficient are Petrol/Diesel cars?
" (Diesel engines generally achieve greater fuel efficiency than petrol (gasoline) engines. Passenger car diesel engines have energy efficiency of up to 41% but more typically 30%, and petrol engines of up to 37.3%, but more typically 20%. That is one of the reasons why diesels have better fuel efficiency than equivalent petrol cars. A common margin is 25% more miles per gallon for an efficient turbodiesel.) "
Source - Wikipedia.
P.S. - I'm a Novice hence can Not provide a Definite answer...but surely my Seniors would Nail it.
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EDIT - I forgot to factor in the Loss of Power thru Transmission Lines.
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& I donno how to calculate that.
But yeah, if it's a simple Comparison between an Electric Motor vs a Internal Combustion Engine...then the Electric Motor has it fair & square.
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Loss of Energy due to Heat would be the likely reason.
Electric motors after an hour of operation would get warmed up considerably...but the I.C. Engine gets incredibly Hot within a few minutes.
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If all Transport was Electric...Air Pollution would occur around just Power Plants.
Would be easy to tackle particulate matter & other unfriendly gases by attaching Filters at the chimneys.
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But gas vehicles n fuel vehicles, Especially Diesel ones pollute the inner parts of a city.
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Perhaps reason being all public transports like trains, metros, subways, buses & even aircrafts are seeing newer electric models.
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(But yes, i donno how to factor in scrapping all gas/fuel modes of private transport n replace them with batteries.
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That perhaps would take alot of mining & dynamite)
Public transportation seems like a good resolve.
Efficient & Economical.
& I also Wonder, why the heck can people not just ' Work from Home '.
I Understand it won't be applicable & feasible for everyone, but still.
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Be safe from road accidents, until a huge earthquake brings down your house, or perhaps a mega asteroid flattens the Earth.
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(If it ain't already flat)
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lol...sory Mods!
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Post by: alancalverd on 31/05/2021 16:58:32
According to the manufacturers, making an electric car from scratch releases around 26 - 30 tonnes of carbon dioxide, as much as a diesel car would emit in 100,000 miles. So replacing internal combustion vehicles before they are worn out will increase global CO2 levels.
Manufacturing and siting land-based wind generators emits about 600 tonnes of CO2 per delivered megawatt. Offshore wind is slightly more efficient in terms of mean delivered power per unit installed capacity, but they require rather more concrete and steel to build - say 1000 tonnes of CO2 per MW. If we replace all the cars in the UK with electric cars we will need to install another 30 GW of delivered power, and if that all comes from wind at an average of 20% of installed capacity, that means 150,000,000 tonnes of CO2 must be released before we reach "zero carbon" car travel.
Buses, diesel trains and trucks in total account for about the same amount of energy as cars in the UK, so to replace all modes of transport with electric traction you can double the above figures.
Long term, of course, you will be running on a replacement basis, so carbon dioxide emissions will drop to about one tenth to one twentieth of the peak. The key question, then, is when are you prepared to release all the CO2 necessary to make the change? All at once and hope the climate scientists are wrong, or over say 20 - 50 years as the oil runs out anyway?
In the interim, before all the new windmills come on stream, you have to make up the balance with gas-generated electricity, as at present, except you will need to double the number of power stations and burn a lot of fossil fuel to do so. And then scrap them.
Electric cars are a great idea, just 100 years too late to save the planet.
Post by: Petrochemicals on 31/05/2021 17:33:34
The UK presently consumes 100 million toe of gas, yet the uk alone would use 100 million toe extra every year just for transport if generated from gas, meaning the uk would be consuming gas at twice the rate it is at present. If this is extended world wide we would halve the time to readopting coal as our main fuel source. This would be very very bad as a gas boiler is far more efficient than an electric radiator run from coal power.
Post by: Zer0 on 31/05/2021 19:54:53
Listener David was wondering:
"Hypothetically speaking, if all modes of transport were electric, would this cause greater pollution (in terms of output from power stations) than conventional petrol or diesel modes of transport?"
🙄
Just in Case David was seeking a Blunt & Plaid answer...
Then, if all modes of transport were Electric, then Additional Power would be Required to charge them.
Hence Residential + Commercial + Industrial + Transportation = Would eventually make Power Plants Alot more Polluting than at the Current stage.
That would Simply be Worse!
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What would Really matter or change the paradigm, is from Where & How that additional Electricity is Generated.
Nuclear + Geothermal + Renewables would do the Trick.
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P.S. - Oil will dry up...Natural Gas shall disappear...& Then the Only thing left would be Dark Black Coal.
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(Hope & Wish ITER works out)
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Post by: evan_au on 01/06/2021 01:06:12
Quote from: David
in terms of output from power stationsUnfortunately, I think Dave was basing his question on a false premise.
The cost of coal, oil & gas is increasing, as we exhaust the easier deposits.
- The cost of renewables is decreasing
- Making coal, then oil less economic over time
- The last to go will be gas turbines, because they are less-polluting than coal, and have a more rapid response for peak-hour demands.
One of the challenges of this fossil vs renewables debate is that you can't easily store electricity.
- But that is exactly what electric vehicles do.
- And installing solar cells is something for which owners of electric vehicles have a strong incentive
- Yes, it will need a lot of low-power chargers, and a communications infrastructure to manage it, but an increasing fraction of our electricity grid will be from renewables.
Whether we would replace our entire existing fleet of vehicles over the next 20 years remains to be seen.
- The increasing convenience of accessing Uber and similar services means that more people can do without a personal car
- Especially in our more crowded cities
- If and when self-driving taxis become a realistic alternative, ride hire will become far more affordable than it is today (you don't have to feed and house the driver).
Post by: wolfekeeper on 01/06/2021 05:41:10
Sadly, in the short term, the answer is yes.The studies say no.
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According to the manufacturers, making an electric car from scratch releases around 26 - 30 tonnes of carbon dioxide, as much as a diesel car would emit in 100,000 miles.And what about the carbon dioxide needed to make the diesel car? That's zero is it??? Of course not, it's pretty similar, and then there's the diesel emissions on top.
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So replacing internal combustion vehicles before they are worn out will increase global CO2 levels.The CO2 emissions during manufacturing are not an automatic given. Electric car manufacturers are already using electrical power more in production, and so their CO2 emissions are dropping as the electrical power systems become greener.
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Manufacturing and siting land-based wind generators emits about 600 tonnes of CO2 per delivered megawatt. Offshore wind is slightly more efficient in terms of mean delivered power per unit installed capacity, but they require rather more concrete and steel to build - say 1000 tonnes of CO2 per MW.The generators repay these CO2 debts in a few months.
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If we replace all the cars in the UK with electric cars we will need to install another 30 GW of delivered power, and if that all comes from wind at an average of 20% of installed capacity, that means 150,000,000 tonnes of CO2 must be released before we reach "zero carbon" car travel.Displacing multiple times that in avoided fossil fuel usage.
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Buses, diesel trains and trucks in total account for about the same amount of energy as cars in the UK, so to replace all modes of transport with electric traction you can double the above figures.Again, displacing far dirtier modes of transportation.
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Long term, of course, you will be running on a replacement basis, so carbon dioxide emissions will drop to about one tenth to one twentieth of the peak. The key question, then, is when are you prepared to release all the CO2 necessary to make the change? All at once and hope the climate scientists are wrong, or over say 20 - 50 years as the oil runs out anyway?Oil's not going to run out, unconventional sources are massive, easily enough to completely destroy the climate.
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In the interim, before all the new windmills come on stream, you have to make up the balance with gas-generated electricity, as at present, except you will need to double the number of power stations and burn a lot of fossil fuel to do so. And then scrap them.No, because you can install renewable energy and build new electric vehicles AT THE SAME TIME. They're complementary.
Post by: alancalverd on 01/06/2021 12:25:48
And what about the carbon dioxide needed to make the diesel car? That's zero is it???Yes, because we already have 30,000,000 perfectly good ICE cars and enough recyclable scrap to keep them running for another 20 years with negligible additional carbon emission, particularly if the recycling processes are mainly electrical.
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The CO2 emissions during manufacturing are not an automatic given.Yes they are. I quoted from an exclusively EC manufacturer's website. I think they know what they are doing.
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The generators repay these CO2 debts in a few months.1 MW = 20 cars. 1000 tons of CO2 = 20 cars x 200,000 miles. That's a very big "few".
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Displacing multiple times that in avoided fossil fuel usage.eventually. My question is whether it is better to crank up CO2 production now in order to eliminate it some time in the future, and if so, what is the tolerable maximum?
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No, because you can install renewable energy and build new electric vehicles AT THE SAME TIME.That rather presupposes a solution to the implicit equation I have just outlined, followed by a rational government policy. No chance.
Post by: Bored chemist on 01/06/2021 12:38:02
Why not "upcycle" them and make them electric?And what about the carbon dioxide needed to make the diesel car? That's zero is it???Yes, because we already have 30,000,000 perfectly good ICE cars and enough recyclable scrap to keep them running for another 20 years with negligible additional carbon emission.
Post by: Bored chemist on 01/06/2021 12:39:34
Electric cars are a great idea, just 100 years too late to save the planet.Reminds me of the observation that the best time to plant a tree is 20 years ago.The second best time is today.
Post by: alancalverd on 01/06/2021 13:37:26
Why not "upcycle" them and make them electric?Worth a thought. There are a couple of companies turning out amazing 600 HP electric versions of classic Porsches and Jaguars which certainly saves on R&D and metalbashing, but you need to reorganise the suspension to carry half a ton of battery instead of 200 kg of V8. And you still have to make the battery and build the power stations and charging points.
Post by: alancalverd on 01/06/2021 13:41:24
Reminds me of the observation that the best time to plant a tree is 20 years ago.The second best time is today.Bu a tree is "all good" whenever you plant it. My concern is that rapid change to electric traction may do more harm than good if you accept that CO2 is a Bad Thing, so the best time was either 100 years ago or gradually over the next 20 years*, but not today.
*when zero-carbon fusion power will be only 5 years away, or maybe 25.
Post by: vhfpmr on 01/06/2021 13:57:31
Post by: vhfpmr on 01/06/2021 14:10:12
Bu a tree is "all good" whenever you plant it.According to the expert on the Thunberg program recently, forests generate more carbon for the first 15 years, then spend the next 15 years offsetting what they've just produced before they become carbon neutral.
Here, from the 18th minute: https://www.bbc.co.uk/iplayer/episode/p099f5k2/greta-thunberg-a-year-to-change-the-world-series-1-episode-3
Post by: alancalverd on 01/06/2021 14:18:54
VW reckon their electric Golf will pay it's way after 77600 miles, based on the EU mix of electricity sources. Their analysis includes other sources too. https://www.volkswagenag.com/en/news/stories/2019/04/from-the-well-to-the-wheel.html#Adequately close to my estimate of 100,000 miles for the Polestar 2 versus a 2-liter Skoda (they use VW diesel engines).
Post by: Petrochemicals on 01/06/2021 16:49:54
VW reckon their electric Golf will pay it's way after 77600 miles, based on the EU mix of electricity sources. Their analysis includes other sources too. https://www.volkswagenag.com/en/news/stories/2019/04/from-the-well-to-the-wheel.html#Yes but how long will the government continue to subsidise electric vehicles before it snaps the trap shut. EVs currently pay no road tax and no fuel duty and no vat on their electric. The government makes about 60 pence per litre of petrol that goes toward subsidising electric vehicles and their energy, plus the road tax pays for the roads. If all the petrol cars disappeared tomorrow how would the government pay for everything, including subsidised nuclear and wind? I suspect they will ram up roat tax for EVs and tax the cars. I suspect they would introduce a climate change levvy making evs far less appealing
Post by: wolfekeeper on 01/06/2021 17:10:57
No, because roughly half of the ICE vehicle carbon emissions today is the fuel they burn and more if they were magically recycled with no further emissions, so that's not happening, and don't forget that electric cars are highly recyclable too. As the current fleet of fossil cars wear out and the manufacturers pull their fingers out, they're going to be replaced more and more with electric cars. That's already happening in fact more than you seem to understand, with plug-in hybrids; they're electric cars too.And what about the carbon dioxide needed to make the diesel car? That's zero is it???Yes, because we already have 30,000,000 perfectly good ICE cars and enough recyclable scrap to keep them running for another 20 years with negligible additional carbon emission, particularly if the recycling processes are mainly electrical.
Post by: Petrochemicals on 01/06/2021 19:07:30
The volkswagen statistics mentioned are thoes of paying for itself are in terms of co2No, because roughly half of the ICE vehicle carbon emissions today is the fuel they burn and more if they were magically recycled with no further emissions, so that's not happening, and don't forget that electric cars are highly recyclable too. As the current fleet of fossil cars wear out and the manufacturers pull their fingers out, they're going to be replaced more and more with electric cars. That's already happening in fact more than you seem to understand, with plug-in hybrids; they're electric cars too.And what about the carbon dioxide needed to make the diesel car? That's zero is it???Yes, because we already have 30,000,000 perfectly good ICE cars and enough recyclable scrap to keep them running for another 20 years with negligible additional carbon emission, particularly if the recycling processes are mainly electrical.
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Comparison of the carbon footprint of the e-Golf and Golf diesel: The e-Golf has a better CO₂ balance after approximately 125,000 kilometers.it is unclear what the recycled co2 footprint would be though if made from recycled materials. I suspect the VW statistics are virginal lithium production, from cradle to gate.
Post by: alancalverd on 01/06/2021 19:08:25
As the current fleet of fossil cars wear out and the manufacturers pull their fingers out, they're going to be replaced more and more with electric cars.And windmills and electricity distribution systems and gaspower stations for when the wind doesn't blow.
Electric traction is great as a marginal substitute, but the activity of replacing the entire ICE fleet will generate a lot more CO2 than just building the cars. The question is whether you want to do it now or later.
Post by: alancalverd on 01/06/2021 19:12:58
it is unclear what the recycled co2 footprint would be though if made from recycled materialsThere is already a fair bit of scrap in every car. But it's worth considering whether re-grinding a crankshaft and valve seats emits more CO2 than melting the entire engine and re-casting it as an electric motor frame. I think not. Definitely worth a visit to Malta or Cuba to see just how long an ICE vehicle can be made to last with a bit of cannibalisation and binder twine.
Post by: Petrochemicals on 01/06/2021 19:22:25
I was thinking of the battery really lalan, it seems to account for about 50 percent of embodied carbon. Being lithium, poking around in a car battery will not end happily.it is unclear what the recycled co2 footprint would be though if made from recycled materialsThere is already a fair bit of scrap in every car. But it's worth considering whether re-grinding a crankshaft and valve seats emits more CO2 than melting the entire engine and re-casting it as an electric motor frame. I think not. Definitely worth a visit to Malta or Cuba to see just how long an ICE vehicle can be made to last with a bit of cannibalisation and binder twine.
Post by: wolfekeeper on 02/06/2021 00:13:01
Post by: vhfpmr on 21/06/2021 23:50:57
Plot.png (16.79 kB . 462x438 - viewed 2997 times)
Post by: alancalverd on 22/06/2021 00:05:07
Post by: vhfpmr on 22/06/2021 00:40:20
Post by: Colin2B on 22/06/2021 08:50:29
What galvanised me into plotting that was arguments with other cyclists who seem to think that muscle is a perpetual motion machine that produces free energy out of thin air.that surprises me, what do they think they are doing when they carb load or take on a sugar drink during a spin. Have they never suffered ‘the bonk’?
Nice plot by the way.
Post by: Bored chemist on 22/06/2021 08:55:55
More seriously, the "uptick" at the left hand side of the walking curve may tell you a lot.
Post by: alancalverd on 22/06/2021 14:32:33
More seriously, the "uptick" at the left hand side of the walking curve may tell you a lot.Two immediate thoughts. If you don't move, you are still burning carbon, so the CO2 emission per unit distance is infinite. And a ceremonial "slow march" or certain traditional folk dance steps uses more muscle power than normal walking as the rising foot is held airborne and the planted leg has to actively stabilise the body against swaying.
Post by: Bored chemist on 22/06/2021 16:15:27
If you don't move, you are still burning carbon, so the CO2 emission per unit distance is infiniteAnd I think that's where the "uptick" is going.
Most of the CO2 produced by 4 adults on bikes would also be produced by 4 adults in a car.
Did that get added to the "car" figure?
Post by: wolfekeeper on 22/06/2021 18:37:21
On what grid? The e-golf is rated at 275 wH/mile. On the UK grid (averages 181g/kWh) that would be 50 g Co2/mile.
Post by: Petrochemicals on 22/06/2021 21:12:24
The bicycle is by far the most efficient means of transport
https://en.m.wikipedia.org/wiki/Bicycle_performance
60 Watts 15 miles
Post by: Bored chemist on 22/06/2021 21:35:12
Utter rubbish.Why did you post a link that doesn't say anything about CO2 emissions?
The bicycle is by far the most efficient means of transport
https://en.m.wikipedia.org/wiki/Bicycle_performance
60 Watts 15 miles
Post by: acsinuk on 23/06/2021 09:39:51
Could be E scooters and bikes are the way forward as their batteries are tiny compared to a large luxury cars.
Post by: vhfpmr on 23/06/2021 16:01:52
what do they thinkI had a long argument with someone on a cycling forum who was absolutely adamant that he eats no more if he cycles than when he doesn't. It started after I had pointed out that the cost of cycling he proposed was less that the cost of the food that fuels him.
Post by: vhfpmr on 23/06/2021 16:07:37
You get the same uptick with cycling if you include basal metabolism as well as the energy burnt by the exercise, which gives an interesting indication of the most energy efficient speed.More seriously, the "uptick" at the left hand side of the walking curve may tell you a lot.Two immediate thoughts. If you don't move, you are still burning carbon, so the CO2 emission per unit distance is infinite. And a ceremonial "slow march" or certain traditional folk dance steps uses more muscle power than normal walking as the rising foot is held airborne and the planted leg has to actively stabilise the body against swaying.
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Post by: vhfpmr on 23/06/2021 16:11:47
Most of the CO2 produced by 4 adults on bikes would also be produced by 4 adults in a car.It includes energy needed to power the bike, and energy used in the effort of driving, it doesn't include basal metabolism because you still pay for that if you lay in bed, and don't travel.
Did that get added to the "car" figure?
Post by: vhfpmr on 23/06/2021 16:15:34
On what grid?It's for the EU average mix of energy, VW don't specify the data for UK.
Post by: vhfpmr on 23/06/2021 16:21:46
60 Watts 15 milesEr, the watt is a unit of power, not energy, let alone CO2
The bicycle is a very efficient machine compared to walking, as can be seen from the plot, but nothing much else in the system is.
The human body is only 18-25% efficient compared to ~90% of an electric motor.
Motors are reversible, muscle isn't.
The agricultural sector is the biggest source of CO2 in the economy.
A lot of calories come from meat, which is an extremely inefficient way of producing food.
About 27% of all the food produced is wasted.
Post by: vhfpmr on 23/06/2021 18:02:17
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The data for it are as follows:
Rider/driver weight: 80kg ( a round number 6% below national average, because cyclists are likely to be a bit slimmer)
CO2 emissions: The top plot is for 2.5 g/kcal which is about correct for the UK where something like 27% of all food produced goes to waste, and the average Brit consumes 82kg of meat PA. (Meat is the biggest culprit for agricultural CO2)
The plots in dotted lines are 1.6 g/kcal, and based on my own diet, which is less than a third of the national average meat consumption, and has almost no domestic waste. Although I eat meat, the low waste makes my emissions comparable with a vegan.
I've also included two figures for the electric car, the higher one is the total lifecycle emissions including manufacture and recycling, whilst the lower one the emissions for mileage alone. The relevant figure depends on the choice being made: if you're deciding whether to buy a bike or a car, then the lifecycle emissions are the relevant figure. If you're deciding whether to drive or leave the car at home and use the bike, then only the mileage is relevant.
As you can see, if you want to compete with a car that's already been manufactured, you're going to need a pretty good diet.
References:
https://www.volkswagenag.com/en/news/stories/2019/04/from-the-well-to-the-wheel.html
http://prevention.sph.sc.edu/tools/docs/documents_compendium.pdf
https://ourworldindata.org/environmental-impacts-of-food?country= - carbon-footprint-of-food-products
http://shrinkthatfootprint.com/food-carbon-footprint-diet
https://files.digital.nhs.uk/9D/4195D5/HSE19-Overweight-obesity-rep.pdf
http://www.wrap.org.uk/sites/files/wrap/Estimates_%20in_the_UK_Jan17.pdf
My own diet spreadsheet
Post by: Bored chemist on 23/06/2021 18:39:34
Post by: alancalverd on 23/06/2021 19:50:29
Most of the CO2 produced by 4 adults on bikes would also be produced by 4 adults in a car.Yes but it's now divided by 50 mph. Not a lot of cyclists can manage that.
Did that get added to the "car" figure?
Post by: Bored chemist on 23/06/2021 20:07:41
You get the same uptick with cycling if you include basal metabolism as well as the energy burnt by the exercise,You should also get it for driving a car. The driver is still breathing, even if the car is stationary. (and there's also "idling" fuel)
Post by: alancalverd on 23/06/2021 22:49:59
The train figures become horrendous if you add in the carbon footprint of the infrastructure. HS2 so far has cost over £500,000 per meter without even building a train, let alone running it. Assuming that no money has been wasted on "consultancy fees" to "companies" that have never built a railway, or as "compensation" to "companies" that were not invited to tender, and that no contractor is actually related to a Tory MP, at least half of the money will have been spent on fossil fuel to make or move stuff. Or do I smell incompetence and corruption?
Post by: Petrochemicals on 24/06/2021 00:08:50
extrapolate60 Watts 15 milesEr, the watt is a unit of power, not energy, let alone CO2
From the wiki article
"The required food can also be calculated by dividing the output power by the muscle efficiency. This is 18–26%. From the example above, if a 70 kg person is cycling at 15 km/h by expending 60 W and a muscular efficiency of 20% is assumed, roughly 1 kJ/(km∙kg) extra food is required"
Meaning 70kj of food per km, or 2 grams of fat, or 2 grams of diesil biofuel. Or about 5g of CO2.
Or in your imperial terms 8gco2/mile
What do you mean by reversible?
The bicycle is a very efficient machine compared to walking, as can be seen from the plot, but nothing much else in the system is.
The human body is only 18-25% efficient compared to ~90% of an electric motor.
Motors are reversible, muscle isn't.
.
Motors are efficient, but on cars add in battery inefficiencies, charging inefficiencies, aerodynamic drag, rolling resistance, the fact that all of this 2000+kg has to be moved it cannot be anywhere as efficient.
This is before we add in manufacturing and maintenance costings. All of the people who built the car also expended Co2 making it. The extra generation capacity also entails some CO2 production.
Post by: Bored chemist on 24/06/2021 10:12:45
Unlike humans, my diesel car switches off when it's not moving.True, but even if you are sat in traffic, you are still metabolising something like 2400 KCal per day.
That's the equivalent of burning roughly 270 grams of fat per day.
And that produces something like 800 grams of CO2 per day or about 35 grams per hour.
It doesn't make a lot f sense to include that in the "travel" figure- because you aren't traveling.
But it also doesn't include base rate metabolism in the cyclists case and, as far as I can tell, that uptick indicates that they have included it.
So it's not a level playing field.
In the limit, at zero MPH, the rate of production of CO2 is the same for a car or a bike; about 35 grams per person per hour.
So, it's worse for a tandem or for a car with passengers.
That's plainly silly, so it should be subtracted from (or not included in) the figures on the graph.
How much more food does a cyclist need than he would normally consume?
Post by: vhfpmr on 24/06/2021 13:03:27
Since you already have most of the data, perhaps you could add the figures for a train or two.Not for trains I haven't (or buses). It would get quite complicated wouldn't it: rush hour or half-empty, or during lockdown, diesel or electric. Then there's the complication that the route and distance are rarely the same, and a train journey often includes a car to get to the station.
I suppose the reason I posted this was that it's interesting that there isn't as clear a winner as might be supposed, electric car and bike are surprisingly similar, and deciding what's best is quite complicated and dependent on all sorts of individual details. Alan C suggested including showers and laundry, but there's also motive for cycling to consider too. Anyone cycling anyway for health & fitness can choose whether to combine essential journeys with their health rides or keep them separate, which in turn will make a big difference. And as I mentioned previously, it makes a huge difference whether you've already bought the electric car or not, because it's easier for the bike to compete with a car that hasn't yet been made than one parked on the drive. The green thing to do is travel less.
Post by: vhfpmr on 24/06/2021 13:10:44
Yes, but driver CO2 only contributes 4-6% of car total, so it's pretty negligible. I plotted the car at a nominal 30mph, because there's no speed info on that VW reference.You get the same uptick with cycling if you include basal metabolism as well as the energy burnt by the exercise,You should also get it for driving a car. The driver is still breathing, even if the car is stationary. (and there's also "idling" fuel)
Post by: Bored chemist on 24/06/2021 13:12:35
Alan C suggested including showers and laundryGuess again.
but there's also motive for cycling to consider too. Anyone cycling anyway for health & fitness can choose whether to combine essential journeys with their health rides or keep them separate, which in turn will make a big difference.There are two ways to look at that.
You can buy t shirts printed with "I don't run because I like running; I run because I like cake".
Running and cycling are often ways to extend your own life, in spite of hedonism, at the expense of the Earth's resources.
The green thing to do is travel less.And running or cycling for health is doing the opposite.
Mind you, the most "green" thing we can do is die.
Post by: Bored chemist on 24/06/2021 13:18:18
Yes, but driver CO2 only contributes 4-6% of car total, so it's pretty negligible.Not if the car is stationary.
And it's unfair to compare a car doing 30 MPH to a cyclist doing 15 (or a pedestrian doing 5) without taking account of the fact that the person's "tickover" still burns about 100W regardless of how fast they are moving.
If the place I'm heading for is 10 miles away, the journey time is obviously influenced by the speed.
Is it "fair" to penalise the walker because he takes 2 hours, during which his brain uses more energy than it does during a 20 minute car journey?
Post by: vhfpmr on 24/06/2021 13:41:00
And that produces something like 800 grams of CO2 per day or about 35 grams per hour.Which CO2 are you talking about? The CO2 you breathe is what was absorbed when the food grew, the CO2 in my data is what was produced by farm tractors, fertiliser factories, Tesco lorries etc etc. That amounts to about 6000g/day. A mile in a car takes about 2 mins, so 6000/24/30 = 8g/mile. That compares with ~200g/mile for the car itself.
Post by: vhfpmr on 24/06/2021 13:44:35
Not if the car is stationary.If the car is stationary the emissions per mile are infinite, and you don't arrive at your destination. If you're travelling 2 miles to work, it's the emissions per mile that are relevant, not the emissions per hour.
Post by: vhfpmr on 24/06/2021 13:48:54
And running or cycling for health is doing the opposite.Not necessarily, what is the environmental cost of increased healthcare, and what is the health cost of a poor environment.
Not all motoring is essential, going on holiday or for a day out is just hedonism, and there's no health benefit to sitting in a car.
Post by: vhfpmr on 24/06/2021 14:00:50
But it also doesn't include base rate metabolismOn reflection I realised that that USC data is total energy including basal met, so I spent this morning altering my spreadsheet to remove it. There's not a whole lot of difference, because it's not significant. In the case of the motorist, it's not significant because >90% of the CO2 is from the car not the driver, and in the case of the cyclist is not hugely significant because ~90% of the energy is from the cycling not BMR.
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Post by: Bored chemist on 24/06/2021 15:11:58
Ticks.JPG (12.98 kB . 199x179 - viewed 2427 times)I'm puzzled by that data.I'm looking to find data for the difference between how much energy you use because you are moving, and how much you would use if you were not moving.
If I'm not moving then there is obviously zero difference.
So, the limit at zero MPH should be zero. The problem is that the division by the distance leaves that result undefined.
But imagine I'm moving at a vanishingly small rate.
Then, clearly I must only be using a tiny bit of energy; much less than if I was running, for example.
So the graph should fall to very near zero for speeds very near zero (because I'm doing very nearly nothing)
But, with your new graphs, the data seems to be heading in the wrong direction; the uptick is still there.
The rate of use is going up for the case where you do nothing, when common sense says it should be going down.
Based on this scrappy extrapolation, the data seems to suggest that (very nearly) not moving takes produces 220 g of CO2 per mile.
It might be useful to know the rate per unit time, rather than per distance.
Post by: Petrochemicals on 24/06/2021 15:13:51
https://www.exploratorium.edu/cycling/humanpower1.html#:~:text=It%20takes%20less%20energy%20to,times%20more%20efficient%20than%20walking.&text=A%20comparison%20of%20the%20energy,bicycle%20is%20most%20energy-efficient.
Post by: Bored chemist on 24/06/2021 15:58:03
There is even a handy Web page to help with the cycling problemThat page also makes the important point that most cars run of non renewable fossil fuels but people run on renewable food.
https://www.exploratorium.edu/cycling/humanpower1.html#:~:text=It%20takes%20less%20energy%20to,times%20more%20efficient%20than%20walking.&text=A%20comparison%20of%20the%20energy,bicycle%20is%20most%20energy-efficient.
Post by: vhfpmr on 24/06/2021 18:32:47
But, with your new graphs, the data seems to be heading in the wrong direction; the uptick is still there.You're getting far too preoccupied with just two data points out of 23. The reason that I'm satisfied with the data from USC is that it matches very well with my own data.
Firstly, here's a plot of my own daily energy consumption against exercise hours. The data were collected at a mean bodyweight of 71kg, and an average speed of 10.8mph. My average calorie consumption is 477kcal/hr inc. bmr, and 372 excl. bmr, compared with 420 and 357 from the USC data at the same speed & weight. That's an error of 12% and 4%, not a bad correlation for a bit of home science.
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Secondly, I can use the results from a couple of Bruce tests to measure the relationship between workload and heart rate, and then use my training data to convert average heart rate into average speed. The result plotted against the USC data again matches very well at 10-12mph, the speeds I typically cycled at, and the diversion at higher speeds errs on the side of higher energy consumption, not lower.
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Finally, here's the a repeat of the same plot with my data added.
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Nothing much there to suggest the USC data are 'utter rubbish'.
Post by: Bored chemist on 24/06/2021 19:05:27
Firstly, here's a plot of my own daily energy consumption against exercise hours.Neat!
How was that measured?
Post by: vhfpmr on 24/06/2021 19:08:37
"The required food can also be calculated by dividing the output power by the muscle efficiency. This is 18–26%. From the example above, if a 70 kg person is cycling at 15 km/h by expending 60 W and a muscular efficiency of 20% is assumed, roughly 1 kJ/(km∙kg) extra food is required"
So we have 15kph = 9.3mph, and
60W output power = 300W input power at your assumed 20% efficiency.
300W = 1080,000J/hr = 257kcal/hr
257/70 = 3.67 METs
And what does the USC reference that I'm using say:
"bicycling, <10 mph, leisure, to work or for pleasure: 4METs"
You might have the sense to check whether the data you're using is actually different before you try to use it to contradict.
Meaning 70kj of food per km, or 2 grams of fat, or 2 grams of diesil biofuel. Or about 5g of CO2.And where are you accounting for the CO2 emitted by farm machinery, agri-chemical factories, transport, livestock farts etc.?
Or in your imperial terms 8gco2/mile
What do you mean by reversible?A reversible machine is one that will work with the input and output swapped around. You can't put mechanical energy back into a human and refill the stomach.
Motors are efficient, but on cars add in battery inefficiencies, charging inefficiencies, aerodynamic drag, rolling resistance, the fact that all of this 2000+kg has to be moved it cannot be anywhere as efficient.This is all included in the data I'm quoting from the VW reference: manufacturing emissions (43% of which is the battery), emissions during use, and also emissions from recycling at the end of life (tiny). I've already referred to these in my posts.
This is before we add in manufacturing and maintenance costings. All of the people who built the car also expended Co2 making it. The extra generation capacity also entails some CO2 production.
Post by: Petrochemicals on 25/06/2021 01:54:43
the figure is from Wikipedia. The article on cycling efficiency. 1 kj per kg per mile extra food."The required food can also be calculated by dividing the output power by the muscle efficiency. This is 18–26%. From the example above, if a 70 kg person is cycling at 15 km/h by expending 60 W and a muscular efficiency of 20% is assumed, roughly 1 kJ/(km∙kg) extra food is required"
So we have 15kph = 9.3mph, and
60W output power = 300W input power at your assumed 20% efficiency.
300W = 1080,000J/hr = 257kcal/hr
257/70 = 3.67 METs
And what does the USC reference that I'm using say:
"bicycling, <10 mph, leisure, to work or for pleasure: 4METs"
You might have the sense to check whether the data you're using is actually different before you try to use it to contradict.Meaning 70kj of food per km, or 2 grams of fat, or 2 grams of diesil biofuel. Or about 5g of CO2.And where are you accounting for the CO2 emitted by farm machinery, agri-chemical factories, transport, livestock farts etc.?
Or in your imperial terms 8gco2/mile
So you have accounted for the farts of the windfarm workers?What do you mean by reversible?A reversible machine is one that will work with the input and output swapped around. You can't put mechanical energy back into a human and refill the stomach.Motors are efficient, but on cars add in battery inefficiencies, charging inefficiencies, aerodynamic drag, rolling resistance, the fact that all of this 2000+kg has to be moved it cannot be anywhere as efficient.This is all included in the data I'm quoting from the VW reference: manufacturing emissions (43% of which is the battery), emissions during use, and also emissions from recycling at the end of life (tiny). I've already referred to these in my posts.
This is before we add in manufacturing and maintenance costings. All of the people who built the car also expended Co2 making it. The extra generation capacity also entails some CO2 production.
Post by: alancalverd on 25/06/2021 11:56:07
Post by: vhfpmr on 26/06/2021 15:36:07
the figure is from Wikipedia. The article on cycling efficiency. 1 kj per kg per mile extra food.
I've already shown you that your Wikipedia reference is calculating the same energy consumption as my method using the data from the University of South Carolina, that is not the issue! What you and your Wiki reference have taken no account of is the emissions produced by the agriculture that’s growing the food to fuel the rider. You are calculating efficiency from rider's mouth to bicycle wheel, but the calculation of relevance is the efficiency from farmer's field to bicycle wheel.
So you have accounted for the farts of the windfarm workers?
The worker’s farts occur whether they’re running windfarms or working on oil rigs, unlike emissions from cattle, which only occur because we eat meat products. No meat = no cattle farts.
Furthermore, meat is an incredibly inefficient way to produce energy. The efficiency of pork production is only 10%, and for beef it’s just 1%. Eat beef, and you’re effectively throwing away 99% of the resources that were used to produce it, which is why a vegan diet is far more efficient than an omnivorous one.
https://awellfedworld.org/feed-ratios/
Post by: Bored chemist on 26/06/2021 15:39:19
So you have accounted for the farts of the windfarm workers?It's not that sort of "wind".
Post by: Bored chemist on 26/06/2021 15:41:48
Furthermore, meat is an incredibly inefficient way to produce energy.Unless you are feeding kitchen scraps to chickens or pigs.
It's also pretty efficient if you are a hill farmer in the north of the UK where it's too cold and wet to grow anything but grass which is inedible, but which cam be converted to milk or lam which we can eat.
Post by: Petrochemicals on 26/06/2021 16:38:56
Well that sounds like one rule for you and one for me. If there where no windfarms there would not be farts emminating from them.
the figure is from Wikipedia. The article on cycling efficiency. 1 kj per kg per mile extra food.
I've already shown you that your Wikipedia reference is calculating the same energy consumption as my method using the data from the University of South Carolina, that is not the issue! What you and your Wiki reference have taken no account of is the emissions produced by the agriculture that’s growing the food to fuel the rider. You are calculating efficiency from rider's mouth to bicycle wheel, but the calculation of relevance is the efficiency from farmer's field to bicycle wheel.So you have accounted for the farts of the windfarm workers?
The worker’s farts occur whether they’re running windfarms or working on oil rigs, unlike emissions from cattle, which only occur because we eat meat products. No meat = no cattle farts.
Furthermore, meat is an incredibly inefficient way to produce energy. The efficiency of pork production is only 10%, and for beef it’s just 1%. Eat beef, and you’re effectively throwing away 99% of the resources that were used to produce it, which is why a vegan diet is far more efficient than an omnivorous one.
https://awellfedworld.org/feed-ratios/
The cyclist garners his extra energy from the wild grown hazelnuts he gathers cycling down country lanes on sunny summer days, just as the leaves begin to auburn and the August heat is sated by cooler air blowing gently across the hayfields, rather than whizzing along in an electric vehicle powered from wind turbines that even now have to be subsidised as they are not energy efficient, it all comes down to cost, windfarms cost more to produce than they output in the end as the harmful chemicals in the resins and steel co2 that is emitted, the ship that installs them. If they did not use as much energy as gas powered plants they would be a goldmine and no one would ever have needed a subsidy to effectively print money. If they cost more chances are unless they have "gucci" or something written down the side they have used more energy.
The phrasiology you are looking for is "cradle to grave" analysis, or perhaps "cradle to gate" or one of the others.
https://en.m.wikipedia.org/wiki/Life-cycle_assessment
Post by: vhfpmr on 26/06/2021 16:43:16
Firstly, here's a plot of my own daily energy consumption against exercise hours.Neat!
How was that measured?
The calculation is simple enough, but you need lots of data. The more the better. I have a daily record of my weight, calorie intake, and exercise hours going back about 18 years.
The calculation is just
Metabolic rate = energy consumed + weight loss x calorific value of body fat
but the issue is getting enough data to average out the confounding variables.
The issue is that the short term change in weight due to fat is much smaller than the potential weight change due to other factors like hydration and bowel contents. Fortunately fat is cumulative over the long term, whereas the confounding variables aren’t, so you can minimise the errors by averaging a large amount of data over the long term. You also need a lot of averaging to smooth out variations in exercise performance.
For example, if the day’s mismatch between consumed and burnt energy were 200kcal, that's only 26g of body fat, but your weight can easily change by 1kg or more due to dehydration alone. That would be an error of several thousand percent, but fortunately the confounding variables aren't cumulative, and fat is, so you can minimise the error by measuring over long periods of time. Over say 100 days, the effect of a sustained calorie excess accumulates body fat, but the effect of non-cumulative variables is effectively divided by 100.
In order to produce a scattergram with data that doesn’t all cluster in one place, you then need multiple measurements over periods that have a significant variation in exercise hours. There’s about 1600 hours of exercise over a period of 137 weeks in that chart above.
Weighing yourself might sound simple, but there’s a lot you can do to reduce confounding weight variation. I always weigh first thing in the morning after going to the loo, but before eating. That minimises variation in bowel contents.
Accuracy and repeatability of bathroom scales is not good either. If you roll your weight from toe to heel, and left to right, you can expect to see several hundred grams of variation in the reading, so it pays to practice the knack of distributing your weight evenly. If you step on and off the scale repeatedly you also find the reading on most scales varies wildly, so I always take three readings and pick the mean or mode.
Finally, the weights at the start and finish of a measurement period that I use to calculate weight change are not single readings, but 7 day averages. This is only practical if the measurement period is significantly longer than a week.
Post by: vhfpmr on 26/06/2021 16:45:23
That's not generally what's happening though, there are huge areas that are slashed and burnt every year for live stock farming.Furthermore, meat is an incredibly inefficient way to produce energy.Unless you are feeding kitchen scraps to chickens or pigs.
It's also pretty efficient if you are a hill farmer in the north of the UK where it's too cold and wet to grow anything but grass which is inedible, but which cam be converted to milk or lam which we can eat.
Post by: vhfpmr on 26/06/2021 17:55:48
Well that sounds like one rule for you and one for me.
Really?
You disregard all the emissions from cycling but not electric cars and then accuse me of bias?
Pot, kettle, black.
If there where no windfarms there would not be farts emminating from them.
If there were no windfarms the workers would still be farting elsewhere, unless you’re planning to cull them all. On the other hand if there were no livestock farming there’d be no livestock farts.
The cyclist garners his extra energy from the wild grown hazelnuts he gathers cycling down country lanes on sunny summer days, just as the leaves begin to auburn and the August heat is sated by cooler air blowing gently across the hayfields,
The reason we have farming on an industrial scale is that you can’t feed 7 billion people on the pickings from country lanes. The last time humans lived as hunter gatherers the population was only 5 million.
windfarms cost more to produce than they output in the end as the harmful chemicals in the resins and steel co2 that is emitted, the ship that installs them. If they did not use as much energy as gas powered plants they would be a goldmine and no one would ever have needed a subsidy to effectively print money.
The reason windfarms were subsidised has nothing to do with them being uneconomic, it’s because when there were few of them they didn’t have the economy of scale that established fuels already enjoy. Windfarm subsidies have already dropped to an all-time low, and wind is now one of the cheapest sources of electricity:
“the newest wind farms coming online will operate with ‘negative subsidy’. This means operators effectively paying the Government to generate power”
“Offshore wind power will soon be so cheap to produce that it will undercut fossil-fuelled power stations and may be the cheapest form of energy for the UK”
https://inews.co.uk/news/environment/offshore-wind-power-cheap-explained-pay-back-government-subsidies-563941
Thanks to Chinese investment in solar panel technology, solar energy is on the same trajectory too. Fossil fuels will go down the plughole simply because they become uneconomic at an ever-accelerating rate.
Post by: Petrochemicals on 26/06/2021 18:13:26
Not really.Well that sounds like one rule for you and one for me.
Really?
You disregard all the emissions from cycling but not electric cars and then accuse me of bias?
Pot, kettle, black.
You ignore all points such as the CO2 output of factory workers assembling and designers, exaggerated any figure that contradicts your argument. You are also attempting to argue against me rather than the source and go on to crate figures that support your argument.
It takes 2 grams of fat to go 1km on a bike, but according to your creativity, this 2 grammes of fat is actually only 20 percent efficient and even then it is only 1 percent efficient so takes 500 times the figure stated in wikipedia. Utter tosh. 8 grams co2 per mile for a bike.
Post by: alancalverd on 26/06/2021 23:10:03
the north of the UK where it's too cold and wet to grow anything but grassTime was that it was covered with trees and heather that sequester carbon and support all sorts of edible fruit, seeds, and wild animals, but there is more money in beef and lamb (whatever happened to mutton? Far tastier but less profitable!). Nowadays the heather is burnt to encourage new growth because grouse like seedlings rather than mature plants, and are even more profitable than sheep.
Post by: alancalverd on 26/06/2021 23:19:11
My average calorie consumption is 477kcal/hr inc. bmr, and 372 excl. bmr,
372 kcal/hr = 434 watts
Max continuous useful work for one-hour cycle rides is around 100W for most people
so 20% muscle efficiency is about right.
Post by: Bored chemist on 26/06/2021 23:38:51
So, you don't realise how much of your food is actually "eaten" by gut bacteria?Firstly, here's a plot of my own daily energy consumption against exercise hours.Neat!
How was that measured?
The calculation is simple enough, but you need lots of data. The more the better. I have a daily record of my weight, calorie intake, and exercise hours going back about 18 years.
The calculation is just
Metabolic rate = energy consumed + weight loss x calorific value of body fat
but the issue is getting enough data to average out the confounding variables.
The issue is that the short term change in weight due to fat is much smaller than the potential weight change due to other factors like hydration and bowel contents. Fortunately fat is cumulative over the long term, whereas the confounding variables aren’t, so you can minimise the errors by averaging a large amount of data over the long term. You also need a lot of averaging to smooth out variations in exercise performance.
For example, if the day’s mismatch between consumed and burnt energy were 200kcal, that's only 26g of body fat, but your weight can easily change by 1kg or more due to dehydration alone. That would be an error of several thousand percent, but fortunately the confounding variables aren't cumulative, and fat is, so you can minimise the error by measuring over long periods of time. Over say 100 days, the effect of a sustained calorie excess accumulates body fat, but the effect of non-cumulative variables is effectively divided by 100.
In order to produce a scattergram with data that doesn’t all cluster in one place, you then need multiple measurements over periods that have a significant variation in exercise hours. There’s about 1600 hours of exercise over a period of 137 weeks in that chart above.
Weighing yourself might sound simple, but there’s a lot you can do to reduce confounding weight variation. I always weigh first thing in the morning after going to the loo, but before eating. That minimises variation in bowel contents.
Accuracy and repeatability of bathroom scales is not good either. If you roll your weight from toe to heel, and left to right, you can expect to see several hundred grams of variation in the reading, so it pays to practice the knack of distributing your weight evenly. If you step on and off the scale repeatedly you also find the reading on most scales varies wildly, so I always take three readings and pick the mean or mode.
Finally, the weights at the start and finish of a measurement period that I use to calculate weight change are not single readings, but 7 day averages. This is only practical if the measurement period is significantly longer than a week.
Do you know that they used to market tapeworm eggs as a weight loss aid?
Post by: Bored chemist on 26/06/2021 23:39:47
Heather is inedible.the north of the UK where it's too cold and wet to grow anything but grassTime was that it was covered with trees and heather that sequester carbon and support all sorts of edible fruit, seeds, and wild animals, but there is more money in beef and lamb (whatever happened to mutton? Far tastier but less profitable!). Nowadays the heather is burnt to encourage new growth because grouse like seedlings rather than mature plants, and are even more profitable than sheep.
It hardly matters whether you farm animals that eat grass or animals that eat heather.
Post by: vhfpmr on 27/06/2021 11:51:26
So, you don't realise how much of your food is actually "eaten" by gut bacteria?And the relevance of that is what, exactly?
Do you know that they used to market tapeworm eggs as a weight loss aid?
The measurement is how much food is required to fuel a given amount of exercise without gaining or losing weight (from which you can establish how much CO2 arises from growing that food).
If you have to buy a gallon of petrol to drive 40 miles, it doesn't make any difference to your cost of motoring whether it's being used by the engine or gremlins in the petrol tank, unless you have a method of removing the gremlins.
Post by: vhfpmr on 27/06/2021 12:09:37
so 20% muscle efficiency is about right.I calculated my efficiency from the results of my Bruce tests:
Pout Pin Eff
57.5 414 14%
101.2 630 16%
160.2 909 18%
225.5 1206 19%
301.0 1395 22%
I've got some power vs speed data somewhere too, I'll dig it out when I've done the ironing.
Post by: Bored chemist on 27/06/2021 12:34:29
That's fine, if you know that the gremlins eat at a constant rate.So, you don't realise how much of your food is actually "eaten" by gut bacteria?And the relevance of that is what, exactly?
Do you know that they used to market tapeworm eggs as a weight loss aid?
The measurement is how much food is required to fuel a given amount of exercise without gaining or losing weight (from which you can establish how much CO2 arises from growing that food).
If you have to buy a gallon of petrol to drive 40 miles, it doesn't make any difference to your cost of motoring whether it's being used by the engine or gremlins in the petrol tank, unless you have a method of removing the gremlins.
Post by: vhfpmr on 27/06/2021 14:14:39
And if they don't eat at a constant rate, it's of no help unless you have data you can use to calculate what they eat. I have 18 years of data, and yes the relationship between workload and calorie consumption varies a bit from one year to the next, mainly because my fitness varies, nevertheless any measurement of average calorie consumption enables you to measure other parameters relating to it for as long as the relationship holds.That's fine, if you know that the gremlins eat at a constant rate.So, you don't realise how much of your food is actually "eaten" by gut bacteria?And the relevance of that is what, exactly?
Do you know that they used to market tapeworm eggs as a weight loss aid?
The measurement is how much food is required to fuel a given amount of exercise without gaining or losing weight (from which you can establish how much CO2 arises from growing that food).
If you have to buy a gallon of petrol to drive 40 miles, it doesn't make any difference to your cost of motoring whether it's being used by the engine or gremlins in the petrol tank, unless you have a method of removing the gremlins.
People have spoken about BMR on this thread as if it is the constant on the graph, unrelated to workload, but it isn't. BMR also varies with workload, if you sit an athlete and a couch potato together on the couch, they burn calories at a different rate even though their workload is the same. I can see this in my data too.
Post by: vhfpmr on 27/06/2021 14:19:29
I've got some power vs speed data somewhere tooOoh look, 60W at 9mph, just like Wikipedia says:
Power vs Speed.png (10.55 kB . 550x378 - viewed 2266 times)This was produced by calculating regression coefficients for heart rate vs speed from cycling data, then HR vs power by using the stairs as a treadmill.
Post by: alancalverd on 27/06/2021 15:19:40
It hardly matters whether you farm animals that eat grass or animals that eat heather.They take sequestered carbon and oxidise it, so the more animals you have per unit land, the more CO2 they emit. The natural fauna live at a much lower density, so most of the heather gets turned into bog peat rather than sheep fart.
Post by: Petrochemicals on 27/06/2021 16:47:25
It hardly matters, biological entities put out co2 and plants take it in. If not this planet would have been either carbondioxideless or oxygenless a very very long time ago. Tyrannosaurus and friends would not have evolved sort of long time ago. It's a stroke of luck that there is some sort of co-dependancy really. Either that or evolution.It hardly matters whether you farm animals that eat grass or animals that eat heather.They take sequestered carbon and oxidise it, so the more animals you have per unit land, the more CO2 they emit. The natural fauna live at a much lower density, so most of the heather gets turned into bog peat rather than sheep fart.
Post by: alancalverd on 27/06/2021 16:59:45
The Kyoto Protocol, by which the "leaders" of 55 nations agreed to urgent action to reduce carbon dioxide levels, was signed 22 years ago, since when the CO2 level has increased by 12.5% and is accelerating.
Post by: vhfpmr on 27/06/2021 17:14:40
You ignore all points such as the CO2 output of factory workers assembling and designers
What CO2? What workers?
I am not ignoring anything, and neither are VW. The CO2 emissions in the VW analysis are the lifecycle emissions including all the emissions from manufacture and recycling. I have already explained this! The figures in the VW analysis almost exactly match this analysis from Florence University:
https://reader.elsevier.com/reader/sd/pii/S2452321618301690?token=E0FEADA4C6AE10E1D09D0442197B74C27DC834EF653BEC2D8766B2208742B4B2F26A8A67B6C7FB9F6F6DD1E801AB385B&originRegion=eu-west-1&originCreation=20210625101751
It takes 2 grams of fat to go 1km on a bike
Yes, at 15km/h and 60W, that's about right.
Quote
this 2 grammes of fat…
….contains 18kcals = 75kJ (The calorific value of refined fat is 9kcal/g)
So, at 15km/h it takes 4mins = 240s to travel your 1km
And 60W x 240s = 14400J
So we have 14400J output from the body in mechanical power, and
75000J input to the body in food
Efficiency is output/input, so the body efficiency = 14400/75000 = 19.2%
Quote
20 percent efficient
Yes, it is. Just I and Wikipedia have been telling you. This shouldn’t come as a surprise to you, because the Wiki article you keep quoting from says: “a muscular efficiency of 20% is assumed”.
But as I have also repeatedly told you, none of this so far has taken any account whatsoever of the carbon emissions created in producing your 2g of fat. Fat, or any other foodstuff for that matter, doesn’t just appear out of thin air, it takes a lot of farm machinery and other industry and transport to produce it, and this all creates a lot of CO2. This is what you are systematically refusing to acknowledge.
Quote
even then it is only 1 percent efficient so takes 500 times the figure stated in wikipedia.
If the 18kcals (75kJ) required to ride your bike 1km had come from an average diet instead of fat, then the agricultural system producing it would create a total of 2.5g CO2 per kcal, so:
18 x 2.5g = 45g of CO2
which is what I have been presenting to you all along.
Now, if you choose to get your 18kcals from meat products (such as fat) instead of other sources, the CO2 emissions will be much much worse. The reason for this is that if you feed the 18kcals (75kJ) that you could have eaten yourself to an animal instead, you don’t get anywhere near 18 kcals of produce from it in return. The conversion efficiency is about 10% for pork, and 1% for beef, meaning that for every 18 kcals of meat product available to eat, you will have to feed the animal it came from between 180 and 1800 kcals of animal feed during its lifetime.
So, if your cyclist were exclusively fuelled by meat products, the CO2 emissions would be between 10 and 100 times worse than the 45g figure calculated above.
The data I have plotted for you on this thread shows the difference between an average diet and a vegan diet, and also shows the difference between total lifecycle car emissions and the emissions from mileage only, excluding manufacture/recycling, but you choose to ignore all this, and systematically misrepresent what I have said.
Post by: vhfpmr on 27/06/2021 17:23:53
It hardly matters, biological entities put out co2 and plants take it in.More nonsense.
Plants absorb CO2 as they grow, and animals exhale CO2 as they breathe, but in addition, animals belch and fart methane. Methane is a greenhouse gas 80 times more powerful than CO2.
As I explained above, meat eating is bad for the environment, OK when just a rich minority could afford it, but as the poor start eating more meat, it becomes totally unsustainable.
As well as travelling less, we need to eat less meat (and waste less food).
Post by: Petrochemicals on 27/06/2021 17:26:18
You have changed your tune. Can't be bothered to answer or check a long and protracted post, or answer the accusations. You are wrong according to Wikipedia, go and moan at them. 8g co2 per mile for a bike.It takes 2 grams of fat to go 1km on a bike
Yes, at 15km/h and 60W, that's about right.
Quote from: vhfpmr
So we have 15kph = 9.3mph, and
60W output power = 300W input power at your assumed 20% efficiency.
Post by: alancalverd on 27/06/2021 20:41:01
8g co2 per mile for a bike.2 g fat will produce about 7.5 g CO2 when fully oxidised.
Post by: alancalverd on 27/06/2021 20:46:54
Fat, or any other foodstuff for that matter, doesn’t just appear out of thin air,Funny, that. The stuff in my garden seems to do exactly that. Fats, sugars, proteins, carbohydrates, all made out of air and water (which falls out of the air!) when the sun shines. Of course if you like your fats and proteins in a different form, the chickens will convert the bits you don't like (and all the insects that compete for the green stuff) into eggs and chicken meat, but not very efficiently.
Post by: Petrochemicals on 28/06/2021 06:21:54
2g fat was per km, the sources I used stated it was 8 per mile rounded.8g co2 per mile for a bike.2 g fat will produce about 7.5 g CO2 when fully oxidised.
Post by: acsinuk on 30/06/2021 16:39:56
So as population doubles every 75 years so does CO2 if 1% per year is the norm.
See https://www.worldometers.info/world-population/
So whether you use a bike or car or EV it is all the same CO2 will increase with population.
Post by: Bored chemist on 30/06/2021 17:19:14
So whether you use a bike or car or EV it is all the same CO2 will increase with population.Bollocks.
If we were able to stop using fossil fuels- for example, buy switching to renewables like solar power, where would the CO2 come from?
Post by: Petrochemicals on 30/06/2021 18:10:11
What you are all missing is that CO2 emissions and climate change are all linked to world population increases. It is obvious that everyone has a right to live and should expect to be fed with food, grown where there was once forests, eat meat thus increasing animals pro rata, be housed and kept warm and drive a car etc.Yep, a 4 fold increace by 2100 would be on the cards but at the rate we are getting through fossil fuel it will all be gone by 2050, cue famine strife war pestilence. But I forget that the uk`s 5% from renewable will stop world wide conflict.
So as population doubles every 75 years so does CO2 if 1% per year is the norm.
See https://www.worldometers.info/world-population/
So whether you use a bike or car or EV it is all the same CO2 will increase with population.
Post by: alancalverd on 30/06/2021 18:30:12
If we were able to stop using fossil fuels- for example, buy switching to renewables like solar power,I think the "if" gets bigger every day, and will continue to recede until the oil actually runs out. The Kyoto protocol was agreed in 1992, since when atmospheric CO2 has increased by 22% and the human population by 40%. We have to restrict either our population or our aspirations. Far better to do the first.
Post by: Bored chemist on 30/06/2021 18:48:31
Far better to do the first.Why do you keep acting as if it's an "either/ or" thing?
Post by: alancalverd on 30/06/2021 22:43:09
Post by: Bored chemist on 30/06/2021 23:02:47
Most of us would like to see that both the birthrate falls, and the standard of living rises. (like it has in most of the western world over the last 50 years or so)
Which one are you saying is impossible?
Post by: vhfpmr on 01/07/2021 17:14:45
Fat, or any other foodstuff for that matter, doesn’t just appear out of thin air,Funny, that. The stuff in my garden seems to do exactly that. Fats, sugars, proteins, carbohydrates, all made out of air and water (which falls out of the air!) when the sun shines. Of course if you like your fats and proteins in a different form, the chickens will convert the bits you don't like (and all the insects that compete for the green stuff) into eggs and chicken meat, but not very efficiently.
If you think you can feed 7bn mouths without producing CO2, try shutting down the global agricultural industry, and see how far people get subsistence farming in their own gardens. In the days of mediaeval peasant farming, it took 57% of the population working the land just to feed everyone, now, with the aid of mechanised, industrialised agriculture, it takes just 1.2%.
https://ourworldindata.org/employment-in-agriculture
Post by: vhfpmr on 01/07/2021 17:18:06
You have changed your tune. Can't be bothered to answer or check a long and protracted post, or answer the accusations. You are wrong according to Wikipedia, go and moan at them. 8g co2 per mile for a bike.It takes 2 grams of fat to go 1km on a bike
Yes, at 15km/h and 60W, that's about right.Quote from: vhfpmrSo we have 15kph = 9.3mph, and
60W output power = 300W input power at your assumed 20% efficiency.
I haven’t changed anything.
In that post you are quoting from I spelt out step by step where all the energy is going to and coming from, and you selectively quote two lines and cut the rest out in an attempt to accuse me of contradicting myself.
From the post above:
Quote
2 grammes of fat…
….contains 18kcals = 75kJ (The calorific value of refined fat is 9kcal/g)
So, at 15km/h it takes 4mins = 240s to travel your 1km
And 60W x 240s = 14400J
So we have 14400J output from the body in mechanical power, and
75000J input to the body in food
Efficiency is output/input, so the body efficiency = 14400/75000 = 19.2%
Power is energy/time, so if I divide the input and output energies above by 240s I can express exactly the same equation in terms power instead:
Efficiency = (14400J/240s)/(75000J/240s)
= 60W/312.5W = 19.2%
If you think you know better, why don’t you show us your own calculation of the CO2 produced by cycling.
Alan Calverd and Bored Chemist, you’re quite capable of seeing how dishonest he’s being, and yet you just sit there and say nothing.
Post by: vhfpmr on 01/07/2021 17:29:04
Post by: alancalverd on 01/07/2021 20:14:24
In the days of mediaeval peasant farming, it took 57% of the population working the land just to feed everyone, now, with the aid of mechanised, industrialised agriculture, it takes just 1.2%.And if we didn't eat meat, even fewer.
There's a difference between "feeding 7 billion people" and giving them a desirable standard of living. The latter demands an average of at least 5 kW per capita, twice the present total from all sources.
Post by: Petrochemicals on 01/07/2021 20:31:23
.8gco2 per km
Alan Calverd and Bored Chemist, you’re quite capable of seeing how dishonest he’s being, and yet you just sit there and say nothing.
Post by: Petrochemicals on 01/07/2021 22:45:14
You are once again having one rule for your vested interests and another for any evidence against you. That is why you are biased. Please do not ask for another demonstration of this as it is quite boring. Please do not duck the point or evade it in any other way either.
Really?
You disregard all the emissions from cycling but not electric cars and then accuse me of bias?
Pot, kettle, black.
I do not disregard the emissions from going 1km on a bicycle which are 8 games of carbon dioxide per mile, these emissions can come entirely from sources that only emmit oxygen.
You wish to count all other carbon emissions incurred which are embodied in food. All of the workers who produce a car eat food, these are not included in the embodied carbon of products. All of the electricity production and distri ution workers also eat, the people who make the electric car charger also eat. The people who supply the CO2 emitting vehicles to the road pavers also eat. You have not accounted for the CO2 of concrete in powerstations or the steel copper and aluminium of the distribution grid. Etcetera.
You wish to associate the c02 from food with the extremes of co2. You posted
Furthermore, meat is an incredibly inefficient way to produce energy. The efficiency of pork production is only 10%, and for beef it’s just 1%. Eat beef, and you’re effectively throwing away 99% of the resources that were used to produce it, which is why a vegan diet is far more efficient than an omnivorous one.Whilst the CO2 in meat is debatable, a cow in a field is entirely neutral, but you felt the need to post the above. A chicken fed soya from burned down rainforest shipped from Brazil for 2 months has a far higher carbon footprint than a sheep in a field 365 days a year. You have cherry picked the worst examples rather than potatoes or oil or nuts but you are refusing the possibility that a cyclist may well be powering himself from wild grown nuts.
You seem to have some ulterior motive and a pre-agenda. You are having one rule for your interest and another for any evidence against it.
You are calculating efficiency from rider's mouth to bicycle wheel, but the calculation of relevance is the efficiency from farmer's field to bicycle wheel.yes but you wish me to have something different to the method you use. That would be one rule for you one for me.
I doubt they account for co2 from man-made renewable sources, if you could show that I would be most appreciative.Quote from: PetrochemicalsThis is all included in the data I'm quoting from the VW reference: manufacturing emissions (43% of which is the battery), emissions during use, and also emissions from recycling at the end of life (tiny). I've already referred to these in my posts.
Motors are efficient, but on cars add in battery inefficiencies, charging inefficiencies, aerodynamic drag, rolling resistance, the fact that all of this 2000+kg has to be moved it cannot be anywhere as efficient.
This is before we add in manufacturing and maintenance costings. All of the people who built the car also expended Co2 making it. The extra generation capacity also entails some CO2 production.
Cyclist use extra energy but workers don't. This certainly sounds like two rules.
If there were no windfarms the workers would still be farting elsewhere, unless you’re planning to cull them all. On the other hand if there were no livestock farming there’d be no livestock farts.
There is still 8g of co2 in the extra emission from cycling 1km .
Post by: alancalverd on 01/07/2021 22:58:17
a cow in a field is entirely neutralPolitically, maybe, but it is burning carbohydrates (at a rate of around 1.5 W per kg) that would otherwise be sequestered in grass and peat bogs or eventually forest and coal, and thus altering the natural balance of atmospheric to captured carbon dioxide.
A horse (or cow) standing in a field emits as much CO2 in a year as a small car travelling 8000 miles.