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According to Wikipedia, the world's average energy consumption is 12.3Tw. Given that the Earth is gets 1366 W/m² of solar power at 149,597,870km, this means Me

by daeken 10y ago

According to Wikipedia, the world's average energy consumption is 12.3Tw. Given that the Earth is gets 1366 W/m² of solar power at 149,597,870km, this means Mercury gets 9190 W/m² at 57,910,000km. Plugging these together, this tells us that a 12.3Tw solar array of 100% efficiency in Mercury's orbit would have a surface area of 1338 km². Realistically, you'd at least double that, to produce the same power, as solar panels are <50% efficient.

jnicholasp 10y ago
Brilliant, thanks. So how long before we start putting solar panels in close, direct orbit around the Sun?
- iliis 10y ago
  As soon as somebody figures out how to get the energy from the panels back to earth? Assuming we figure out how to economically put them there in the first place...
- guelo 10y ago
  Then we could beam the energy back to earth using lasers so bright that they would burn plasma holes through our atmosphere and precisely target receiving stations where they would vaporize water which would power a steam turbine. Totally doable, I'd say we could get it up and running in a couple years.
  - jnicholasp 10y ago
    This sounds like sarcasm, but yes: solar collectors in close orbit around the sun, huge flying parabolic mirrors focusing solar energy that's already 7-10x more dense than it is at 1 AU, beaming that energy to receivers sitting in orbit around the Earth (perhaps at Lagrange 1 and, via L4/L5, L2 to reach the night side of the planet), relayed in to near earth orbit satellites, and being beamed down to many surface locations at safe intensities that might well be used to boil ocean water, driving steam turbines and producing fresh water (and salt). Such a system could provide energy dense power to the entire solar system (skipping the steam turbine step for most locations, and going pure solar electric), up to large installations for entire planets, and down to individual spaceships. I'm not suggesting we'll do it tomorrow. But within a hundred years, if we get and keep our shit together..?
- effie 10y ago
  The cost would be astronomical, I do not think it would be worth it. Much better to build this here on Earth, only 4x more panels needed, still easier to build and maintain.
- sharpcoder 10y ago
  About the same time we reach Type II Civilization status and can build a Dyson Sphere! https://en.wikipedia.org/wiki/Kardashev_scale#Type.C2.A0II_civilization_methods https://en.wikipedia.org/wiki/Kardashev_scale#Type.C2.A0II_c...
- b34r 10y ago
  Short answer: you can't. The Earth's rotation would make collecting that energy very unwieldy. Individual collectors could act like capacitors, but getting that power down to the planet continuously isn't really doable with any current technology.
  - jnicholasp 10y ago
    You wouldn't beam energy directly from near-solar orbit to the surface of the Earth; you would relay it to orbiting receivers around the planet, which would in turn beam it to the surface, and reaching the night-side as well as day-side.
lallysingh 10y ago
You'd have to add some redundency for the rotation of the planet. 58 earth days per mercurial day.
- daeken 10y ago
  You don't need to be concerned about Mercury's day unless they're on the surface, essentially. You do need to be concerned with the earth's, and their positions relative to the sun.
effie 10y ago
Nitpick, the farthest distance of Mercury from the Sun on its orbit is closer to 0.46 AU and it spends most of the time there, so for safe estimate it is better to take this greater value for planet-Sun distance. I get around 100x100 km collecting square near the Earth and almost 50x50 km near the Mercury. Taking into account efficiency and design constraints, it's safer to estimate more like 200x200 km near the Earth and 100x100 km near the Mercury. Clearly, building this near the Mercury brings little benefit as opposed to building it near the Earth. If we built this on the surface of the Earth (seems cheapest, even if the area would have to be quadrupled due to night and atmosphere) it does look practically achievable in the future. Solar energy could sustain current consumption of the human civilization. Most alternative sources of energy are not rich enough to supplant nuclear energy. Solar energy seems to be the best contender.

by daeken 10y ago

jnicholasp 10y ago

Brilliant, thanks. So how long before we start putting solar panels in close, direct orbit around the Sun?

iliis 10y ago
As soon as somebody figures out how to get the energy from the panels back to earth? Assuming we figure out how to economically put them there in the first place...
guelo 10y ago
Then we could beam the energy back to earth using lasers so bright that they would burn plasma holes through our atmosphere and precisely target receiving stations where they would vaporize water which would power a steam turbine. Totally doable, I'd say we could get it up and running in a couple years.
- jnicholasp 10y ago
  This sounds like sarcasm, but yes: solar collectors in close orbit around the sun, huge flying parabolic mirrors focusing solar energy that's already 7-10x more dense than it is at 1 AU, beaming that energy to receivers sitting in orbit around the Earth (perhaps at Lagrange 1 and, via L4/L5, L2 to reach the night side of the planet), relayed in to near earth orbit satellites, and being beamed down to many surface locations at safe intensities that might well be used to boil ocean water, driving steam turbines and producing fresh water (and salt). Such a system could provide energy dense power to the entire solar system (skipping the steam turbine step for most locations, and going pure solar electric), up to large installations for entire planets, and down to individual spaceships. I'm not suggesting we'll do it tomorrow. But within a hundred years, if we get and keep our shit together..?
effie 10y ago
The cost would be astronomical, I do not think it would be worth it. Much better to build this here on Earth, only 4x more panels needed, still easier to build and maintain.
sharpcoder 10y ago
About the same time we reach Type II Civilization status and can build a Dyson Sphere! https://en.wikipedia.org/wiki/Kardashev_scale#Type.C2.A0II_civilization_methods https://en.wikipedia.org/wiki/Kardashev_scale#Type.C2.A0II_c...
b34r 10y ago
Short answer: you can't. The Earth's rotation would make collecting that energy very unwieldy. Individual collectors could act like capacitors, but getting that power down to the planet continuously isn't really doable with any current technology.
- jnicholasp 10y ago
  You wouldn't beam energy directly from near-solar orbit to the surface of the Earth; you would relay it to orbiting receivers around the planet, which would in turn beam it to the surface, and reaching the night-side as well as day-side.

lallysingh 10y ago

You'd have to add some redundency for the rotation of the planet. 58 earth days per mercurial day.

daeken 10y ago
You don't need to be concerned about Mercury's day unless they're on the surface, essentially. You do need to be concerned with the earth's, and their positions relative to the sun.

effie 10y ago

Nitpick, the farthest distance of Mercury from the Sun on its orbit is closer to 0.46 AU and it spends most of the time there, so for safe estimate it is better to take this greater value for planet-Sun distance. I get around 100x100 km collecting square near the Earth and almost 50x50 km near the Mercury. Taking into account efficiency and design constraints, it's safer to estimate more like 200x200 km near the Earth and 100x100 km near the Mercury. Clearly, building this near the Mercury brings little benefit as opposed to building it near the Earth. If we built this on the surface of the Earth (seems cheapest, even if the area would have to be quadrupled due to night and atmosphere) it does look practically achievable in the future. Solar energy could sustain current consumption of the human civilization. Most alternative sources of energy are not rich enough to supplant nuclear energy. Solar energy seems to be the best contender.