1,955
edits
File:solar-land-requirements.png: Difference between revisions
no edit summary
(World map: If all energy came from solar panels, how much land would we need? The land is shown in white. We would need approximately 0.8% of Earth's surface. <small>Just for comparison, crop land is about 2.9% of Earth's surface, and pasture land is about 5.4% of Earth's surface.</small> ==Methodology== Land required for solar panels, if * all energy came from solar photovoltaics, and * everyone on Earth lived a "first-world" lifestyle. Map projection: equirectangular Not counted in...) |
No edit summary |
||
| Line 55: | Line 55: | ||
|<nowiki>20%</nowiki> | |<nowiki>20%</nowiki> | ||
|<nowiki>How much of the land is suitable for placing solar panels</nowiki> | |<nowiki>How much of the land is suitable for placing solar panels</nowiki> | ||
|<nowiki>We're trying to keep the solar panels as close to humans as possible - including on city land. But cities have limited space to put solar panels - in general, rooftops are the way to go. An educated guess says that rooftops are about 20% of city land. 20% is also a good compromise outside the city - you don't want to block out all the sun in the ecosystems.</ | |<nowiki>We're trying to keep the solar panels as close to humans as possible - including on city land. But cities have limited space to put solar panels - in general, rooftops are the way to go. An educated guess says that rooftops are about 20% of city land. 20% is also a good compromise outside the city - you don't want to block out all the sun in the ecosystems.</nowiki> | ||
}} | }} | ||
| Line 78: | Line 78: | ||
# load files | # load files | ||
pop << data/population.data-float64-8640x4320 | pop << data/[[:File:population.data-float64-8640x4320|population.data-float64-8640x4320]] | ||
earth << data/blue-marble-posterized.png | earth << data/[[:File:blue-marble-posterized.png|blue-marble-posterized.png]] | ||
# convert 'pop' to population density (people per km^2) | # convert 'pop' to population density (people per km^2) | ||
pop @@ quantity_to_density | pop @@ quantity_to_density | ||
# resize 'pop' to fit the 'earth' background | # resize 'pop' to fit the 'earth' background | ||
pop :: earth.r | pop :: earth.r | ||
# make 'pop' represent "for each pixel, what fraction of the land is solar land" | # make 'pop' represent "for each pixel, what fraction of the land is solar land" | ||
pop *= 0. | pop *= 0.00053790026 # km^2 per person needed for solar | ||
pop @@ spread | pop @@ spread | ||
# darken the background | # darken the background | ||
earth.r *= 0.5 | earth.r *= 0.5 | ||
earth.g *= 0.5 | earth.g *= 0.5 | ||
earth.b *= 0.5 | earth.b *= 0.5 | ||
# show the solar land in white | # show the solar land in white | ||
earth.r += pop | earth.r += pop | ||
| Line 103: | Line 103: | ||
earth.g <= 1 | earth.g <= 1 | ||
earth.b <= 1 | earth.b <= 1 | ||
# save | # save | ||
earth >> data/solar-land-requirements.png | earth >> data/solar-land-requirements.png | ||
| Line 115: | Line 115: | ||
From the "stats" output from the last line: | From the "stats" output from the last line: | ||
Sum: 4293152.303951 | Sum: 4293152.303951 | ||
This means there is | This means there is 4293152 km^2 of solar land. | ||
Divide this by the Earth's surface (510072000 km^2), and you get '''0.8%'''. | Divide this by the Earth's surface (510072000 km^2), and you get '''0.8%'''. | ||
| Line 124: | Line 124: | ||
==Would your city need [[solar farms]]?== | ==Would your city need [[solar farms]]?== | ||
{{calc | {{calc | ||
|solar_land_per_capita | |1 / solar_land_per_capita | ||
|people per km^2 | |people per km^2 | ||
}} | }} | ||
| Line 133: | Line 133: | ||
* Otherwise, all energy could be generated within the city (rooftops, probably). | * Otherwise, all energy could be generated within the city (rooftops, probably). | ||
But this is | But this is be an oversimplification.<br /> | ||
Some things to consider: | Some things to consider: | ||
* Every city defines its borders differently - this could bias the official stats of "population density". | * Every city defines its borders differently - this could bias the official stats of "population density". | ||
* If [[factories]] are in some industrial area outside the city, their solar panels could be there instead. | * If [[factories]] are in some industrial area outside the city, their solar panels could be there instead. | ||
* | * Other factors, shown in the next section: | ||
==Limitations of this analysis== | ==Limitations of this analysis== | ||