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> Back in the prehistoric era a person would have to gather, chop and burn wood for roughly 10 hours a day for six days straight in order to produce the equival

> Back in the prehistoric era a person would have to gather, chop and burn wood for roughly 10 hours a day for six days straight in order to produce the equivalent light of a modern lightbulb shining for about an hour. This feels like a very odd comparison/metric. It doesn't really matter how many lumens/watts it has, I think a better metric is "How much does it take to 'comfortably' light a single room for 1 hour". Surely the amount of wood that would take is not the amount needed from chopping for 10 hours a day/six days straight. Even more than that, I am really suspicious of these numbers. 60 hours worth of wood chopping would give me a giant inferno bonfire that would last much more than an hour, so how was this comparison done? The fact that modern technology is so relatively cheap means that we can afford to waste it or use it to unnecessary extremes, but that doesn't mean we should really use that as the base measure of comparison. I of course understand the overall point the article is trying to make, but the attempt at quantifying the numbers feels like comparing apples to oranges.

tsss 3y ago
This entire article is total bullshit, and could easily qualify as propaganda. The fact is that everything has gotten far more expensive, not cheaper. 30-40 years ago people used incandescent lights everywhere, AC transformers with pitiful efficiency and gas-guzzling V8s and nobody had to weep over their energy bill. Electricity and fuel has become staggeringly more expensive. It's only due to technological advances and higher efficiency that we can still somewhat afford that stuff at all.
tetris11 3y ago
I just found this stackexchange post[1], that claims 350g of wood would be enough to power 1Kwh, but a user points out that half the heat would be lost in exhaust. Maybe that's what the article was referring to, a significant loss of energy to the efficiency of extracting meaningful work from burning wood, with stone age tools. 1: https://sustainability.stackexchange.com/a/4601 https://sustainability.stackexchange.com/a/4601
pests 3y ago
I think they meant a fire itself would need to burn 10 hours a day for 6 days a week - the chopping to support that fire. The light over the duration is as much as a lightbulb for one hour.
- epa 3y ago
  This is why i dont like these kind of studies. Clearly it does not take 60 hours to find a dead tree in the woods, break it down, and light it on fire.
  - adhesive_wombat 3y ago
    Might not be far off if you don't have very effective tools (Peking Man had simple stone tools) or you've exhausted nearby suitable wood supplies like sticks you can just pick up or trees you can tackle, so you have to travel out and drag it back. The original study estimated 10 pounds (5kg) of wood foraged, trimmed and dried per hour of labour. That sounds low with a saw and an axe (and very low with a chainsaw), but might be about right with primitive tools including travel and processing and wood stack maintenance (no tarps either).
- zamadatix 3y ago
  I can't see any combination, length of time burned or length of time to gather the material, where it takes 60 hours to get a fire that outputs as much light as a single lightbulb over one hour.
  - adhesive_wombat 3y ago
    However, a 60W incandescent bulb puts out about 800 lumens, which is about 64 candela. So one bulb-hour is indeed about 60 candle-hours. This is omnidirectional output, useful output may be less. The original paper reports a 21 pounds of firewood was measured to produce 2.1 foot-candles (22 lux) for 3.4 hours. Overall useful fireplace output was estimated at about 1.7 lumen-hours per pound of wood, which is 10 lumens (just under 1 candela) on average for that 21 pound fire. By focusing on light output, and not the heat output, I still think it's an incomplete comparison, as an LED bulb may be very bright and cheap to run, but it won't keep you very warm in a cave in prehistoric Zhoukoudian.
adhesive_wombat 3y ago
Indeed, you also can burn thousands of gallons of jet fuel and the tyres on a 747 actually spin fewer times than the tyres on a Citroen 2CV do just going to the supermarket. The power in a fire is mostly released as heat, both because they're "compact" piles of burning stuff, and because they're more or less "red/yellow" black body radiators. If it was all released as visible light, burning 3 kg of wood (about 12kWh) over 10 hours would be about the brightness as several kilowatts of metal halide stadium floodlamp.
_yb2s 3y ago
This is why I resent the laws banning incandescent lights. I consider myself an environmentalist, and am very careful about wasting electricity. I love the warm dim light from an incandescent and think it helps me fall asleep... the light from one incandescent dimmed to about 20-40W is all I need after sunset, and all I want. It's like sitting near a campfire. My house is solar powered, and I keep a window open without even heat even in the winter - my utility bills are negative from my solar array. Yet it is "normal" to create massive light pollution with hundreds of watts of LEDs, heating and lighting an entire house including unoccupied rooms, and nearly everybody has LED lights on the front porch and backyard that they leave on all night long. Pisses me off that lighting and electricity are so cheap that people have no regard for it, and yet my minuscule usage is nowadays categorically illegal /rant
- comfypotato 3y ago
  Just use an LED that produces the same color. They 100% exist. I agree that incandescent is better than cold LED. A little shopping and consumer research will 100% find you exactly the LED you want.
  - _yb2s 3y ago
    It doesn't look or feel the same to me. Maybe something to do with CRI (I don't really understand that). I am not switching to LEDs... It would be wasteful to throw away something that works great and replace it with something new that doesn't work as well. I like incandescent, and my 40 year old reading lamp and a few extra bulbs will last forever running a few hours a night dimmed to ~20W.
    - badcppdev 3y ago
      "This is why I resent the laws banning incandescent lights." and "my 40 year old reading lamp and a few extra bulbs will last forever running a few hours a night dimmed to ~20W." You resent the laws although they barely affect you. And it's time for me to take a break from discussion threads.
    - 3y ago
wolverine876 3y ago
Nordhaus makes clear in the actual paper that it's a very, very rough estimate based on a reconstruction of wood burning in their own fireplace. https://news.ycombinator.com/item?id=36234570 https://news.ycombinator.com/item?id=36234570
ilyt 3y ago
Also the fact the wood would be used for heating and/or cooking too

tsss 3y ago

This entire article is total bullshit, and could easily qualify as propaganda. The fact is that everything has gotten far more expensive, not cheaper. 30-40 years ago people used incandescent lights everywhere, AC transformers with pitiful efficiency and gas-guzzling V8s and nobody had to weep over their energy bill. Electricity and fuel has become staggeringly more expensive. It's only due to technological advances and higher efficiency that we can still somewhat afford that stuff at all.

tetris11 3y ago

I just found this stackexchange post[1], that claims 350g of wood would be enough to power 1Kwh, but a user points out that half the heat would be lost in exhaust. Maybe that's what the article was referring to, a significant loss of energy to the efficiency of extracting meaningful work from burning wood, with stone age tools. 1: https://sustainability.stackexchange.com/a/4601 https://sustainability.stackexchange.com/a/4601

pests 3y ago

I think they meant a fire itself would need to burn 10 hours a day for 6 days a week - the chopping to support that fire. The light over the duration is as much as a lightbulb for one hour.

epa 3y ago
This is why i dont like these kind of studies. Clearly it does not take 60 hours to find a dead tree in the woods, break it down, and light it on fire.
- adhesive_wombat 3y ago
  Might not be far off if you don't have very effective tools (Peking Man had simple stone tools) or you've exhausted nearby suitable wood supplies like sticks you can just pick up or trees you can tackle, so you have to travel out and drag it back. The original study estimated 10 pounds (5kg) of wood foraged, trimmed and dried per hour of labour. That sounds low with a saw and an axe (and very low with a chainsaw), but might be about right with primitive tools including travel and processing and wood stack maintenance (no tarps either).
zamadatix 3y ago
I can't see any combination, length of time burned or length of time to gather the material, where it takes 60 hours to get a fire that outputs as much light as a single lightbulb over one hour.
- adhesive_wombat 3y ago
  However, a 60W incandescent bulb puts out about 800 lumens, which is about 64 candela. So one bulb-hour is indeed about 60 candle-hours. This is omnidirectional output, useful output may be less. The original paper reports a 21 pounds of firewood was measured to produce 2.1 foot-candles (22 lux) for 3.4 hours. Overall useful fireplace output was estimated at about 1.7 lumen-hours per pound of wood, which is 10 lumens (just under 1 candela) on average for that 21 pound fire. By focusing on light output, and not the heat output, I still think it's an incomplete comparison, as an LED bulb may be very bright and cheap to run, but it won't keep you very warm in a cave in prehistoric Zhoukoudian.

adhesive_wombat 3y ago

Indeed, you also can burn thousands of gallons of jet fuel and the tyres on a 747 actually spin fewer times than the tyres on a Citroen 2CV do just going to the supermarket. The power in a fire is mostly released as heat, both because they're "compact" piles of burning stuff, and because they're more or less "red/yellow" black body radiators. If it was all released as visible light, burning 3 kg of wood (about 12kWh) over 10 hours would be about the brightness as several kilowatts of metal halide stadium floodlamp.

_yb2s 3y ago

This is why I resent the laws banning incandescent lights. I consider myself an environmentalist, and am very careful about wasting electricity. I love the warm dim light from an incandescent and think it helps me fall asleep... the light from one incandescent dimmed to about 20-40W is all I need after sunset, and all I want. It's like sitting near a campfire. My house is solar powered, and I keep a window open without even heat even in the winter - my utility bills are negative from my solar array. Yet it is "normal" to create massive light pollution with hundreds of watts of LEDs, heating and lighting an entire house including unoccupied rooms, and nearly everybody has LED lights on the front porch and backyard that they leave on all night long. Pisses me off that lighting and electricity are so cheap that people have no regard for it, and yet my minuscule usage is nowadays categorically illegal /rant

comfypotato 3y ago
Just use an LED that produces the same color. They 100% exist. I agree that incandescent is better than cold LED. A little shopping and consumer research will 100% find you exactly the LED you want.
- _yb2s 3y ago
  It doesn't look or feel the same to me. Maybe something to do with CRI (I don't really understand that). I am not switching to LEDs... It would be wasteful to throw away something that works great and replace it with something new that doesn't work as well. I like incandescent, and my 40 year old reading lamp and a few extra bulbs will last forever running a few hours a night dimmed to ~20W.
  - badcppdev 3y ago
    "This is why I resent the laws banning incandescent lights." and "my 40 year old reading lamp and a few extra bulbs will last forever running a few hours a night dimmed to ~20W." You resent the laws although they barely affect you. And it's time for me to take a break from discussion threads.
  - 3y ago

wolverine876 3y ago

Nordhaus makes clear in the actual paper that it's a very, very rough estimate based on a reconstruction of wood burning in their own fireplace. https://news.ycombinator.com/item?id=36234570 https://news.ycombinator.com/item?id=36234570

ilyt 3y ago

Also the fact the wood would be used for heating and/or cooking too