6 ms·

Some people here seem to be confusing electricity usage and energy usage. As the Wikipedia article highlights, the average Swiss uses about 5kW (that's 5kWh pe

by FabHK 4y ago

Some people here seem to be confusing electricity usage and energy usage. As the Wikipedia article highlights, the average Swiss uses about 5kW (that's 5kWh per hour), of which only about 10% are electricity. Similarly, about 10% are car usage, or about 0.5kW. If we take the average car to develop on average 50kW, and assume an efficiency of 1 (for the sake of the argument), then they use a car around 1% of the time or about 15 minutes a day (less if efficiency is <1, as it is). ETA some more reference points: A human eats around 10,000kJ per day = 86400 seconds, let's call it 100,000s, so 10,000kJ/100ks = 100J/s = 100W, about as much as a bright lightbulb (the old fashioned ones, not LED). The sun gives us about 1kW of power per square meter. Say photovoltaic cells have an efficiency of 10%, and the sun shines 6 hours a day (=25%), then we are talking around 25W/m². So, the average Swiss uses the energy corresponding to about 50 people working for him or 200m² of PV, the average US citizen of 120 people or 480m² (5000 sq feet), and the goal here is to push it down to 20 people or 80m² PV. Great reference: the books by Vaclav Smil, eg. How the World Really Works.

markvdb 4y ago
15 kWh of electricity for 100 km of car transportation is realistic for a defensively driven modest electric car. At 500W, that's about 80 km of car use per day. In an electric Hummer or similar, your car energy budget would be gone in 35 km. In a fossil fuel Hummer, getting to the bakery 10 km away might be possible, but only one way.
phkahler 4y ago
A good EV will get about 3 miles per kWhr. So 20kwh recharged over night will get you 60 miles per day. IMHO EVs need MUCH larger batteries to facilitate longer range driving or deviations from a daily routine, but that doesn't change the typical energy usage much.
- neon_electro 4y ago
  How much longer range driving do you personally need? I drove a 2018 Chevy Bolt EV 12,000 miles per year on average for four years (totaled it this past Memorial Day weekend). Never got stranded/ran out of juice. Plenty of fast charging (55kW doesn't even reach 1 C (https://en.wikipedia.org/wiki/Battery_charger#C-rate https://en.wikipedia.org/wiki/Battery_charger#C-rate) so I can basically fast charge with no concern for my long-term battery health), plenty of slow charging (1kW on my home 120V EVSE), 60kWh was more than enough for trips to Montréal, Vermont, and Chicago (from Philadelphia) over those four years.
  - officeplant 4y ago
    As someone that often travels across texas. I need a lot more range, but its a unique case. It doesn't help that I also need a van and Fords E-Transit line can barely push 130 miles on a charge when its partially loaded down. Even looking at long range teslas they don't have enough juice to make it past stretches of chargerless road going from Texas to Colorado to visit friends, even before the losses from having to drive uphill.
    - neon_electro 4y ago
      >I need a van Say no more - I totally understand the situation you're in and a Chevy Bolt EV would obviously not fit your needs.
      - officeplant 4y ago
        Trust me I wish it did. I really like the styling of the new Bolt. I tested one out at the local chevy dealer during the whole battery replacement fiasco's beginnings.
    - sliken 4y ago
      That doesn't sound right. I drove from Sacramento (elevation 30 feet), over the sierras (7200 feet or so), across many mountain ranges in Nevada, through Utah, and through most of Wyoming and came nowhere close to running out of power. Literally I packed the car, hit the listen button, and said "Navigate to Denver, Colorado". Is any route from Texas to Colorado really have less charging than Wyoming (the least populated state)? I found 20+ superchargers between Houston and Denver. Even with a family of 3, dog, packed car, and bikes on the back I had no problems with Sacramento -> Denver, only in the most deserted stretches of Wyoming did I need anywhere close to half of my range. I looked for the sparsest charging and it does indeed look like it's Wyoming, it's 360 miles from east to west and has 5 super chargers on 80. Judging by eye the longest stretch is Rock Springs WY to Rawlins WY and that's only 108 miles. Even on Secondary highways that don't show up at the state level maps there's charger stations in Wichita Falls TX, Childress TX, Amarillo TX, Clayton NM, and Trinidad CO. From there Salida (West 147 miles) or Colorado Springs (North 130 miles) will get you to the rest of the state. Salida to Montrose (130 miles) gets you to west slope. Keep in mind elevation doesn't hurt that much, and while I have gotten a bit worried when I'm at under 60% climbing to a 14k foot peak, I was very surprised to end up with over 80% once I descended again. This is all just using the Telsa charging network, there's many other places to charge as well.
- ericmay 4y ago
  What EVs are you using for comparison? For something like a Standard Range Tesla Model 3 where you have around 260 miles of range when charged to full you don't really need to make any different life decisions w.r.t daily routine or even longer distance travel. I think the main problem is affordability right now there. But EVs that satisfy basically all of someone's need have been in the market for years. Though the real change needs to be in using cars for daily needs in the first place.
  - s0rce 4y ago
    Charging infrastructure is a bit of an issue if you can't easily charge at home or work consistently. Tesla supercharger network is good for long trips though, other brands lack there and you do need to change your long distance travel a bit.
    - ericmay 4y ago
      Yea that's true though I think it's a short-term problem.
  - riversflow 4y ago
    > . . .or even longer distance travel. I mean, this is completely false if you are someone who doesn’t mind a little discomfort (which seems to becoming rapidly uncommon). When I was in my early 20s many Fridays saw me leaving for an all-night 500+ mile drive(one drive I did several times was 900 miles) to visit my friends at university. Even recently, when I go backpacking I typically drive non-stop many hundreds of miles.
    - ggreer 4y ago
      People have run this experiment. A 1,000 mile road trip in a Tesla is about 8% slower than a gas car.[1] That's 90 minutes over 19 hours of driving, and the difference would have been smaller had they charged the car overnight. Battery and charging technology is only getting better, so that gap will narrow over time. Also consider that if most of your driving is not road trips, EVs save time compared to gas cars. You plug the car in when you get home and wake up with a full tank, so to speak. 1. https://www.youtube.com/watch?v=vXzuFprlyrw https://www.youtube.com/watch?v=vXzuFprlyrw
- thatfrenchguy 4y ago
  > A good EV will get about 3 miles per kWhr A mediocre one will, à good one will do ~4-4.2, especially if you don’t drive at 80mph/130kph.
  - neon_electro 4y ago
    I think it's fair to assume 3mi/kWh as far as that's the realistic efficiency in winter time with the heat on. That's the information people new to EVs need to know - the fact that efficiency goes up when conditions are better is gravy.
    - sokoloff 4y ago
      I've driven a Nissan LEAF for 8 winters in New England. On a 50+ mile average, I've never seen worse than 3.3mi/kWh and almost always see 3.6-3.8 in the winter and 3.9-4.1 in the summer. (The car has a heat pump cabin heater, seat heaters, and steering wheel heat.) If I saw 3.0, I'd be looking for the flat tire or a checkered flag.
      - neon_electro 4y ago
        Sounds like my experience when I had a Leaf with a heat pump. The Bolt does not, so it uses a lot more energy to keep the cabin warm.
  - pavon 4y ago
    Yeah our Chevy Bolt averages 4.5 miles/kWh, with mostly city driving including about 15% energy used for heating/cooling (20% during 8 months of winter/summer, 5% during 4 months of fall/spring)
    - moffkalast 4y ago
      Iirc the Lightyear Zero can do over 6, plus it charges while driving.
      - 4y ago
- netsharc 4y ago
  Makes me wonder if the next invention would be battery packs that you can put into your car for long trips, so your car stays light for the majority of the time, when you just need it for in-city commute. Ideally the battery packs would be shared so the "gas" station of the future has them ready for you to rent. Obviously the issue is high demand during weekends and school vacation times, and much lower demand otherwise...
  - wrycoder 4y ago
    I recollect that the original Teslas towed a small gas generator for long trips.
    - FullyFunctional 4y ago
      I don't recall that at all. It was true for Tzero, the vehicle from AC Propulsion that inspired the Roadster (and provided the very initial, but broken electronics). Tesla has never promoted hybrid propulsion.
      - wrycoder 4y ago
        That’s possible. I remember an interview with Eberhard back in the day, I think before Musk, where he described the trailer and also the concept of plugging the cars into the grid during the day to contribute energy to the grid.
        FullyFunctional 4y ago
        I believe that but no Roadster was produced before Elon and I’m not aware that Tesla ever made such a trailer
  - tzs 4y ago
    A few years ago there was a company building test cars with aluminum air batteries. Aluminum air batteries have something like 4x as much energy for a given volume as lithium ion, and they were getting over 1000 miles of range. The downside of aluminum air batteries is that they are not rechargeable, so the idea would be to design the cars so that the batteries can quickly be swapped. The discharged battery can be recycled. It was an interesting idea.
OJFord 4y ago
[Ignore me, I misread. Original comment below.] > 5kW (that's 5kWh per hour) It's 5kW for an hour - but I think you understand that, and implicitly mean something like 'per hour continuously/on average over time' (where the 'over time' makes us dimensionally ok again).
- japanuspus 4y ago
  OP's comment makes perfect sense to me, but how I have read your comment three times without understanding what it is you want to communicate?
  - deleted 4y ago
    [deleted]
  - OJFord 4y ago
    Yeah, I re-read, realise I just said the same thing in reverse. I misread as other commenter having the kW/kWh other way around. Ignore! (I'd delete, but can't after reply.)
ddalex 4y ago
A "normalized" person eats about 2000 kilocalories per day, so that's ~95W. Math checks out.
solardev 4y ago
Great breakdown!
jiggawatts 4y ago
Related to this, one of the most brilliant insights about "how the world works" is the term: energy slave. A good question to ask people is: How much work do you think can be done using the energy in a barrel of oil? As in, how much equivalent labour can you get out of it? Think of lifting heavy objects, pumping water, that kind of thing where it can be done by either a person or a machine fueled by oil. Most people will say something like "a few days of work" or somesuch. The reality is closer to a fit adult male doing backbreaking labour all day every day like a slave for a full year. Using up a barrel of oil is the same as having a slave toiling away for you for a year! One barrel = one energy slave for a year. Put in those terms, a few things start to make sense: At about $100-$150 per barrel, energy slaves are fantastically cheap, undercutting even the most impoverished human labourers in the most economically disadvantaged countries. Even some of the poorest people on Earth make about $300 annually. This means that having and using oil is an incredible boost to an economy, as each barrel burnt is effectively a very-nearly-free labourer adding to the output of the workforce. This is why many countries are so obsessed about controlling their supply of oil. The United States, of course, but also many western countries. People in the US use an average of about 20 barrels of oil annually, which is the equivalent of having 20 slaves, each! That's not even counting coal, nuclear, and natural gas. Effectively, each person in the United States is about as wealthy as a very rich person in Ancient Rome. Think senator, or similar. But this makes sense: a typical person in the US can travel internationally on a whim, and enjoy fantastic luxuries that Romans couldn't even dream of. Take the oil away, and the wealth goes away. Of course, other energy slaves can be substituted, but the point is the same -- our wealth is largely due to this "uncomplaining" workforce that is cheaper than the cheapest human labour.

by FabHK 4y ago

markvdb 4y ago

15 kWh of electricity for 100 km of car transportation is realistic for a defensively driven modest electric car. At 500W, that's about 80 km of car use per day. In an electric Hummer or similar, your car energy budget would be gone in 35 km. In a fossil fuel Hummer, getting to the bakery 10 km away might be possible, but only one way.

phkahler 4y ago

A good EV will get about 3 miles per kWhr. So 20kwh recharged over night will get you 60 miles per day. IMHO EVs need MUCH larger batteries to facilitate longer range driving or deviations from a daily routine, but that doesn't change the typical energy usage much.

neon_electro 4y ago
How much longer range driving do you personally need? I drove a 2018 Chevy Bolt EV 12,000 miles per year on average for four years (totaled it this past Memorial Day weekend). Never got stranded/ran out of juice. Plenty of fast charging (55kW doesn't even reach 1 C (https://en.wikipedia.org/wiki/Battery_charger#C-rate https://en.wikipedia.org/wiki/Battery_charger#C-rate) so I can basically fast charge with no concern for my long-term battery health), plenty of slow charging (1kW on my home 120V EVSE), 60kWh was more than enough for trips to Montréal, Vermont, and Chicago (from Philadelphia) over those four years.
- officeplant 4y ago
  As someone that often travels across texas. I need a lot more range, but its a unique case. It doesn't help that I also need a van and Fords E-Transit line can barely push 130 miles on a charge when its partially loaded down. Even looking at long range teslas they don't have enough juice to make it past stretches of chargerless road going from Texas to Colorado to visit friends, even before the losses from having to drive uphill.
  - neon_electro 4y ago
    >I need a van Say no more - I totally understand the situation you're in and a Chevy Bolt EV would obviously not fit your needs.
    - officeplant 4y ago
      Trust me I wish it did. I really like the styling of the new Bolt. I tested one out at the local chevy dealer during the whole battery replacement fiasco's beginnings.
  - sliken 4y ago
    That doesn't sound right. I drove from Sacramento (elevation 30 feet), over the sierras (7200 feet or so), across many mountain ranges in Nevada, through Utah, and through most of Wyoming and came nowhere close to running out of power. Literally I packed the car, hit the listen button, and said "Navigate to Denver, Colorado". Is any route from Texas to Colorado really have less charging than Wyoming (the least populated state)? I found 20+ superchargers between Houston and Denver. Even with a family of 3, dog, packed car, and bikes on the back I had no problems with Sacramento -> Denver, only in the most deserted stretches of Wyoming did I need anywhere close to half of my range. I looked for the sparsest charging and it does indeed look like it's Wyoming, it's 360 miles from east to west and has 5 super chargers on 80. Judging by eye the longest stretch is Rock Springs WY to Rawlins WY and that's only 108 miles. Even on Secondary highways that don't show up at the state level maps there's charger stations in Wichita Falls TX, Childress TX, Amarillo TX, Clayton NM, and Trinidad CO. From there Salida (West 147 miles) or Colorado Springs (North 130 miles) will get you to the rest of the state. Salida to Montrose (130 miles) gets you to west slope. Keep in mind elevation doesn't hurt that much, and while I have gotten a bit worried when I'm at under 60% climbing to a 14k foot peak, I was very surprised to end up with over 80% once I descended again. This is all just using the Telsa charging network, there's many other places to charge as well.
ericmay 4y ago
What EVs are you using for comparison? For something like a Standard Range Tesla Model 3 where you have around 260 miles of range when charged to full you don't really need to make any different life decisions w.r.t daily routine or even longer distance travel. I think the main problem is affordability right now there. But EVs that satisfy basically all of someone's need have been in the market for years. Though the real change needs to be in using cars for daily needs in the first place.
- s0rce 4y ago
  Charging infrastructure is a bit of an issue if you can't easily charge at home or work consistently. Tesla supercharger network is good for long trips though, other brands lack there and you do need to change your long distance travel a bit.
  - ericmay 4y ago
    Yea that's true though I think it's a short-term problem.
- riversflow 4y ago
  > . . .or even longer distance travel. I mean, this is completely false if you are someone who doesn’t mind a little discomfort (which seems to becoming rapidly uncommon). When I was in my early 20s many Fridays saw me leaving for an all-night 500+ mile drive(one drive I did several times was 900 miles) to visit my friends at university. Even recently, when I go backpacking I typically drive non-stop many hundreds of miles.
  - ggreer 4y ago
    People have run this experiment. A 1,000 mile road trip in a Tesla is about 8% slower than a gas car.[1] That's 90 minutes over 19 hours of driving, and the difference would have been smaller had they charged the car overnight. Battery and charging technology is only getting better, so that gap will narrow over time. Also consider that if most of your driving is not road trips, EVs save time compared to gas cars. You plug the car in when you get home and wake up with a full tank, so to speak. 1. https://www.youtube.com/watch?v=vXzuFprlyrw https://www.youtube.com/watch?v=vXzuFprlyrw
thatfrenchguy 4y ago
> A good EV will get about 3 miles per kWhr A mediocre one will, à good one will do ~4-4.2, especially if you don’t drive at 80mph/130kph.
- neon_electro 4y ago
  I think it's fair to assume 3mi/kWh as far as that's the realistic efficiency in winter time with the heat on. That's the information people new to EVs need to know - the fact that efficiency goes up when conditions are better is gravy.
  - sokoloff 4y ago
    I've driven a Nissan LEAF for 8 winters in New England. On a 50+ mile average, I've never seen worse than 3.3mi/kWh and almost always see 3.6-3.8 in the winter and 3.9-4.1 in the summer. (The car has a heat pump cabin heater, seat heaters, and steering wheel heat.) If I saw 3.0, I'd be looking for the flat tire or a checkered flag.
    - neon_electro 4y ago
      Sounds like my experience when I had a Leaf with a heat pump. The Bolt does not, so it uses a lot more energy to keep the cabin warm.
- pavon 4y ago
  Yeah our Chevy Bolt averages 4.5 miles/kWh, with mostly city driving including about 15% energy used for heating/cooling (20% during 8 months of winter/summer, 5% during 4 months of fall/spring)
  - moffkalast 4y ago
    Iirc the Lightyear Zero can do over 6, plus it charges while driving.
    - 4y ago
netsharc 4y ago
Makes me wonder if the next invention would be battery packs that you can put into your car for long trips, so your car stays light for the majority of the time, when you just need it for in-city commute. Ideally the battery packs would be shared so the "gas" station of the future has them ready for you to rent. Obviously the issue is high demand during weekends and school vacation times, and much lower demand otherwise...
- wrycoder 4y ago
  I recollect that the original Teslas towed a small gas generator for long trips.
  - FullyFunctional 4y ago
    I don't recall that at all. It was true for Tzero, the vehicle from AC Propulsion that inspired the Roadster (and provided the very initial, but broken electronics). Tesla has never promoted hybrid propulsion.
    - wrycoder 4y ago
      That’s possible. I remember an interview with Eberhard back in the day, I think before Musk, where he described the trailer and also the concept of plugging the cars into the grid during the day to contribute energy to the grid.
      - FullyFunctional 4y ago
        I believe that but no Roadster was produced before Elon and I’m not aware that Tesla ever made such a trailer
- tzs 4y ago
  A few years ago there was a company building test cars with aluminum air batteries. Aluminum air batteries have something like 4x as much energy for a given volume as lithium ion, and they were getting over 1000 miles of range. The downside of aluminum air batteries is that they are not rechargeable, so the idea would be to design the cars so that the batteries can quickly be swapped. The discharged battery can be recycled. It was an interesting idea.

OJFord 4y ago

[Ignore me, I misread. Original comment below.] > 5kW (that's 5kWh per hour) It's 5kW for an hour - but I think you understand that, and implicitly mean something like 'per hour continuously/on average over time' (where the 'over time' makes us dimensionally ok again).

japanuspus 4y ago
OP's comment makes perfect sense to me, but how I have read your comment three times without understanding what it is you want to communicate?
- deleted 4y ago
  [deleted]
- OJFord 4y ago
  Yeah, I re-read, realise I just said the same thing in reverse. I misread as other commenter having the kW/kWh other way around. Ignore! (I'd delete, but can't after reply.)

ddalex 4y ago

A "normalized" person eats about 2000 kilocalories per day, so that's ~95W. Math checks out.

solardev 4y ago

Great breakdown!

jiggawatts 4y ago

Related to this, one of the most brilliant insights about "how the world works" is the term: energy slave. A good question to ask people is: How much work do you think can be done using the energy in a barrel of oil? As in, how much equivalent labour can you get out of it? Think of lifting heavy objects, pumping water, that kind of thing where it can be done by either a person or a machine fueled by oil. Most people will say something like "a few days of work" or somesuch. The reality is closer to a fit adult male doing backbreaking labour all day every day like a slave for a full year. Using up a barrel of oil is the same as having a slave toiling away for you for a year! One barrel = one energy slave for a year. Put in those terms, a few things start to make sense: At about $100-$150 per barrel, energy slaves are fantastically cheap, undercutting even the most impoverished human labourers in the most economically disadvantaged countries. Even some of the poorest people on Earth make about $300 annually. This means that having and using oil is an incredible boost to an economy, as each barrel burnt is effectively a very-nearly-free labourer adding to the output of the workforce. This is why many countries are so obsessed about controlling their supply of oil. The United States, of course, but also many western countries. People in the US use an average of about 20 barrels of oil annually, which is the equivalent of having 20 slaves, each! That's not even counting coal, nuclear, and natural gas. Effectively, each person in the United States is about as wealthy as a very rich person in Ancient Rome. Think senator, or similar. But this makes sense: a typical person in the US can travel internationally on a whim, and enjoy fantastic luxuries that Romans couldn't even dream of. Take the oil away, and the wealth goes away. Of course, other energy slaves can be substituted, but the point is the same -- our wealth is largely due to this "uncomplaining" workforce that is cheaper than the cheapest human labour.