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The amount of energy sent our way from the sun every day is more than enough (I half recall a fact that one day of sunshine has the same energy as all the fossi

The amount of energy sent our way from the sun every day is more than enough (I half recall a fact that one day of sunshine has the same energy as all the fossil fuels left on earth, someone correct me). I think with solar getting cheaper all the time the challenge is going to become storing energy cleanly and distributing it efficiently.

trothamel 8y ago
Okay, in December 2017, the US produced 345,939 GWH of electricity, of which 1,476 was solar. https://www.eia.gov/electricity/monthly//epm_table_grapher.php?t=epmt_1_01 https://www.eia.gov/electricity/monthly//epm_table_grapher.p... If you look at the best spots in the US in December, they seem to get about 4,500 watt hours per square meter per day. https://www.solar-electric.com/learning-center/general-solar-information/solar-insolation-maps.html https://www.solar-electric.com/learning-center/general-solar... So that means we'd need 76,875 square kilometers of solar to match the current generation of the US, not counting losses from storage. That's between the size of South Carolina, and West Virginia, just coated with solar panels.
- neolefty 8y ago
  Or 70% of Nevada. I for one welcome our paving-the-deserts-with-solar-panels robot overlords.
  - cfadvan 8y ago
    It doesn’t help to capture all of that energy if we can’t store and transmit it efficiently.
    - neolefty 8y ago
      For sure! And I think that a massive increase of storage will make transmission much easier, by allowing us to time-shift transmission—at the expense of efficiency. 1. generate solar power during the day in Nevada and store it nearby 2. trickle it cross-country at night—when the grid is under-utilized—to distributed storage facilities, where demand will be higher the next day 3. use it the next day, or store and forward again That way, long-distance transmission won't need the same massive upgrades—high-temp superconductors! megatons of copper! 7-figure transformers!—as if we had to use the solar power right away.
- philipkglass 8y ago
  Yes, that's huge. The big numbers can look overwhelming. Huge land-use changes that we've already made would look overwhelming if considered as a single monolithic project. Solar facility construction isn't going to be a single monolithic project any more than the existing American biofuel or fossil fuel systems were. http://farmdocdaily.illinois.edu/2016/04/corn-consumption-and-acreage.html http://farmdocdaily.illinois.edu/2016/04/corn-consumption-an... 2016 numbers: about 93.6 million acres planted for corn. About 5.2 billion bushels out of 14.4 billion bushels of corn yield went to corn ethanol. If harvest and land area are proportionate, that's about 33.7 million acres dedicated to corn ethanol [1]. 33.7 million acres is about 136,000 km^2. The areal energy yield from biofuels is paltry compared to what you can get from solar PV. Manufacturing/installing solar PV is more resource-intense than planting corn. But it's low-maintenance once installed. It doesn't require arable land, weeding, irrigation, fertilizer, or harvesting. [1] Yes, the residual material left after fermentation is also used as animal feed. But the conversion efficiency is low; you're not adding many calories per acre to the human food supply when corn is fermented and leftovers go to cattle.
- glenstein 8y ago
  The good thing about solar is it need not occupy new land. It can be installed on land already "occupied" by buildings. According to NREL, there's enough existing roof space for 1,432 terawatt-hours of annual energy generation from solar, which would be 38.6% of our annual generation. https://www.nrel.gov/docs/fy16osti/65298.pdf https://www.nrel.gov/docs/fy16osti/65298.pdf

trothamel 8y ago

Okay, in December 2017, the US produced 345,939 GWH of electricity, of which 1,476 was solar. https://www.eia.gov/electricity/monthly//epm_table_grapher.php?t=epmt_1_01 https://www.eia.gov/electricity/monthly//epm_table_grapher.p... If you look at the best spots in the US in December, they seem to get about 4,500 watt hours per square meter per day. https://www.solar-electric.com/learning-center/general-solar-information/solar-insolation-maps.html https://www.solar-electric.com/learning-center/general-solar... So that means we'd need 76,875 square kilometers of solar to match the current generation of the US, not counting losses from storage. That's between the size of South Carolina, and West Virginia, just coated with solar panels.

neolefty 8y ago
Or 70% of Nevada. I for one welcome our paving-the-deserts-with-solar-panels robot overlords.
- cfadvan 8y ago
  It doesn’t help to capture all of that energy if we can’t store and transmit it efficiently.
  - neolefty 8y ago
    For sure! And I think that a massive increase of storage will make transmission much easier, by allowing us to time-shift transmission—at the expense of efficiency. 1. generate solar power during the day in Nevada and store it nearby 2. trickle it cross-country at night—when the grid is under-utilized—to distributed storage facilities, where demand will be higher the next day 3. use it the next day, or store and forward again That way, long-distance transmission won't need the same massive upgrades—high-temp superconductors! megatons of copper! 7-figure transformers!—as if we had to use the solar power right away.
philipkglass 8y ago
Yes, that's huge. The big numbers can look overwhelming. Huge land-use changes that we've already made would look overwhelming if considered as a single monolithic project. Solar facility construction isn't going to be a single monolithic project any more than the existing American biofuel or fossil fuel systems were. http://farmdocdaily.illinois.edu/2016/04/corn-consumption-and-acreage.html http://farmdocdaily.illinois.edu/2016/04/corn-consumption-an... 2016 numbers: about 93.6 million acres planted for corn. About 5.2 billion bushels out of 14.4 billion bushels of corn yield went to corn ethanol. If harvest and land area are proportionate, that's about 33.7 million acres dedicated to corn ethanol [1]. 33.7 million acres is about 136,000 km^2. The areal energy yield from biofuels is paltry compared to what you can get from solar PV. Manufacturing/installing solar PV is more resource-intense than planting corn. But it's low-maintenance once installed. It doesn't require arable land, weeding, irrigation, fertilizer, or harvesting. [1] Yes, the residual material left after fermentation is also used as animal feed. But the conversion efficiency is low; you're not adding many calories per acre to the human food supply when corn is fermented and leftovers go to cattle.
glenstein 8y ago
The good thing about solar is it need not occupy new land. It can be installed on land already "occupied" by buildings. According to NREL, there's enough existing roof space for 1,432 terawatt-hours of annual energy generation from solar, which would be 38.6% of our annual generation. https://www.nrel.gov/docs/fy16osti/65298.pdf https://www.nrel.gov/docs/fy16osti/65298.pdf