6 ms·

I remember in one of my engineering classes, we did a depressing calculation. Even if we covered the entire earth with maximally efficient Silicon-based solar

by newbie2020 5y ago

I remember in one of my engineering classes, we did a depressing calculation. Even if we covered the entire earth with maximally efficient Silicon-based solar panels (that would not be feasible to make in reality), we wouldn’t even generate a tenth of the energy the world needs… and our energy demands only keep getting higher

timpattinson 5y ago
Please provide numbers for this if you're going to make such an extroadinary claim.
simonbarker87 5y ago
I think you got that calculation wrong. Most estimates put it at about the size of the South Africa could power the world
salmonlogs 5y ago
Using the efficiency of solar panels available today and the current energy needs of the world you could produce enough power with an area the size of Arizona. Assuming you ignore losses from distribution, storage etc. If you did the calculations say 30 years ago when solar was orders of magnitude less efficient you might have gotten to those numbers, but today we are in a very different situation. Nuclear base load with solar and wind will absolutely provide the vast majority of clean energy for future generations.
morsch 5y ago
https://www.wolframalpha.com/input?i=+556.63+exajoules%2F%28175+kWh%2Fsquare+meter%29 https://www.wolframalpha.com/input?i=+556.63+exajoules%2F%28... 1.6x total area of France Sources (these aren't great, feel free to substitute better numbers from better sources): 175 kWh/m2 per year: https://www.tf.uni-kiel.de/matwis/amat/iss/kap_8/advanced/a8_3_1.html https://www.tf.uni-kiel.de/matwis/amat/iss/kap_8/advanced/a8... About 550 Ej world primary energy usage: https://www.statista.com/statistics/265598/consumption-of-primary-energy-worldwide/ https://www.statista.com/statistics/265598/consumption-of-pr... Obviously this is ignoring energy storage etc etc
hlieberman 5y ago
EIA says world primary energy usage was 6.346×10^20 J in 2020 for the year (https://www.eia.gov/outlooks/ieo/data/pdf/ref/A01_r.pdf https://www.eia.gov/outlooks/ieo/data/pdf/ref/A01_r.pdf) The average peak solar irradiance is 1,000 watts/meter^2. Assuming we get that only for 4 hours a day and no sunlight any other time, that's 1.44×10^7 J/m^2/day, or 5.26×10^9 J/m^2/year. Dividing those numbers together, we get 1.21×10^11 square meters needed. Texas is 6.957×10^11 square meters. You might want to take that class again.
nicoburns 5y ago
> and our energy demands only keep getting higher That’s why a lot of environmentalist’s focus is on reducing energy consumption.
- sofixa 5y ago
  Which is a total nonstarter and dead on arrival. Focus needs to be elsewhere (like nuclear)
  - john_the_writer 5y ago
    Could be both.. My power usage today is way less than half what it was 20 years ago. With remote working, my travel consumption is way way down. Food delivery has all but stopped my need to ever get in my car. I mean it's not the end solution, but it's not a non-starter Nuclear though. 100%
    - samus 5y ago
      Works for those that can work from home. Lots of people can't though.
    - sofixa 5y ago
      > Food delivery has all but stopped my need to ever get in my car. Is it better though? Depends on your car, but someone on a scooter loitering, then going to a restaurant/store for you, and then to your home, and then the same thing again, is drastically less efficient than you doing a round-trip.
      - john_the_writer 5y ago
        Ah.. I mean groceries. I never "order in".. Can't be bothered.

timpattinson 5y ago

Please provide numbers for this if you're going to make such an extroadinary claim.

simonbarker87 5y ago

I think you got that calculation wrong. Most estimates put it at about the size of the South Africa could power the world

salmonlogs 5y ago

Using the efficiency of solar panels available today and the current energy needs of the world you could produce enough power with an area the size of Arizona. Assuming you ignore losses from distribution, storage etc. If you did the calculations say 30 years ago when solar was orders of magnitude less efficient you might have gotten to those numbers, but today we are in a very different situation. Nuclear base load with solar and wind will absolutely provide the vast majority of clean energy for future generations.

morsch 5y ago

https://www.wolframalpha.com/input?i=+556.63+exajoules%2F%28175+kWh%2Fsquare+meter%29 https://www.wolframalpha.com/input?i=+556.63+exajoules%2F%28... 1.6x total area of France Sources (these aren't great, feel free to substitute better numbers from better sources): 175 kWh/m2 per year: https://www.tf.uni-kiel.de/matwis/amat/iss/kap_8/advanced/a8_3_1.html https://www.tf.uni-kiel.de/matwis/amat/iss/kap_8/advanced/a8... About 550 Ej world primary energy usage: https://www.statista.com/statistics/265598/consumption-of-primary-energy-worldwide/ https://www.statista.com/statistics/265598/consumption-of-pr... Obviously this is ignoring energy storage etc etc

hlieberman 5y ago

EIA says world primary energy usage was 6.346×10^20 J in 2020 for the year (https://www.eia.gov/outlooks/ieo/data/pdf/ref/A01_r.pdf https://www.eia.gov/outlooks/ieo/data/pdf/ref/A01_r.pdf) The average peak solar irradiance is 1,000 watts/meter^2. Assuming we get that only for 4 hours a day and no sunlight any other time, that's 1.44×10^7 J/m^2/day, or 5.26×10^9 J/m^2/year. Dividing those numbers together, we get 1.21×10^11 square meters needed. Texas is 6.957×10^11 square meters. You might want to take that class again.

nicoburns 5y ago

> and our energy demands only keep getting higher That’s why a lot of environmentalist’s focus is on reducing energy consumption.

sofixa 5y ago
Which is a total nonstarter and dead on arrival. Focus needs to be elsewhere (like nuclear)
- john_the_writer 5y ago
  Could be both.. My power usage today is way less than half what it was 20 years ago. With remote working, my travel consumption is way way down. Food delivery has all but stopped my need to ever get in my car. I mean it's not the end solution, but it's not a non-starter Nuclear though. 100%
  - samus 5y ago
    Works for those that can work from home. Lots of people can't though.
  - sofixa 5y ago
    > Food delivery has all but stopped my need to ever get in my car. Is it better though? Depends on your car, but someone on a scooter loitering, then going to a restaurant/store for you, and then to your home, and then the same thing again, is drastically less efficient than you doing a round-trip.
    - john_the_writer 5y ago
      Ah.. I mean groceries. I never "order in".. Can't be bothered.