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Some solar panels on house roofs to compensate the house consumption is fine... But when I see such pictures, I always wonder about the impact of massive solar

by illys 6y ago

Some solar panels on house roofs to compensate the house consumption is fine... But when I see such pictures, I always wonder about the impact of massive solar panels on albedo. Just like wearing a black t-shirt in the sun in summer. Indeed it is changing a red-ish reflecting soil into a huge black surface in an already hot location. I mean this is not carbon emitting, but this surely produces a significant local warming. So I am cautious about creating massive solar panel parks because of that. I have never found any study that would count the calorific impact of turning black square kms in sunny places, and what impact it would have on global warming if we go massive.

foxyv 6y ago
If you want to know more about this, you can look up "Heat Islands." This causes areas with higher albedo (Usually asphalt roads and parking lots in urban areas) to increase local temperatures, especially at night. It definitely has a measurable impact on the surrounding area. https://www.epa.gov/heatislands#:~:text=Heat%20islands%20are%20urbanized%20areas,as%20forests%20and%20water%20bodies https://www.epa.gov/heatislands#:~:text=Heat%20islands%20are.... https://en.wikipedia.org/wiki/Urban_heat_island https://en.wikipedia.org/wiki/Urban_heat_island
- illys 6y ago
  Thanks, despites it is a bit different for the night: asphalt has an inertia that returns the heat at night. The solar panels are rather thin to have such inertia. I kept looking and I have found some albedo figures: deserts have a typical albedo of 0.25-0.40 (let's round it at 0.33 / source in French: https://www.lelivrescolaire.fr/page/6761182 https://www.lelivrescolaire.fr/page/6761182). Current commercial solar panels yield 15-20% (let's retain 18%) of the received energy into electricity (the purpose) and the rest into local heat. No reflection (they are black), so albedo close to 0, but let's consider the extraction of electricity like a reflection (the energy is not absorbed locally): albedo 0.18. That means making a desert into a solar park changes the albedo of the covered surface from 0.33 to 0.18. It means the absorbed light turned into heat goes from 0.67 to 0.82: +22% sunlight turned into heat. I would be curious to find a modelization that considers all warming effects of solar panels (carbon and non-carbon) to know if it is a good idea to rush into covering deserts like Apple does here.

by illys 6y ago

foxyv 6y ago

If you want to know more about this, you can look up "Heat Islands." This causes areas with higher albedo (Usually asphalt roads and parking lots in urban areas) to increase local temperatures, especially at night. It definitely has a measurable impact on the surrounding area. https://www.epa.gov/heatislands#:~:text=Heat%20islands%20are%20urbanized%20areas,as%20forests%20and%20water%20bodies https://www.epa.gov/heatislands#:~:text=Heat%20islands%20are.... https://en.wikipedia.org/wiki/Urban_heat_island https://en.wikipedia.org/wiki/Urban_heat_island

illys 6y ago
Thanks, despites it is a bit different for the night: asphalt has an inertia that returns the heat at night. The solar panels are rather thin to have such inertia. I kept looking and I have found some albedo figures: deserts have a typical albedo of 0.25-0.40 (let's round it at 0.33 / source in French: https://www.lelivrescolaire.fr/page/6761182 https://www.lelivrescolaire.fr/page/6761182). Current commercial solar panels yield 15-20% (let's retain 18%) of the received energy into electricity (the purpose) and the rest into local heat. No reflection (they are black), so albedo close to 0, but let's consider the extraction of electricity like a reflection (the energy is not absorbed locally): albedo 0.18. That means making a desert into a solar park changes the albedo of the covered surface from 0.33 to 0.18. It means the absorbed light turned into heat goes from 0.67 to 0.82: +22% sunlight turned into heat. I would be curious to find a modelization that considers all warming effects of solar panels (carbon and non-carbon) to know if it is a good idea to rush into covering deserts like Apple does here.