Off-world Power Generation: Difference between revisions

Revision as of 00:22, 29 October 2018

Given:

earth to moon: 238,900 miles
there are four lagrange points that provide constant sun exposure at predictable locations
l1 to earth/moon: 1 million miles
the sun primarily produces visible light (not microwaves or gamma...)
laser transmission is more efficient than microwave, except where earth's atmosphere interferes
current status: A Gigawatt-range microwave system would weigh ~80,000 tons (prohibitively expensive) more lots more
Solar cell efficiency

Premises:

<Earth> <-microwave-- <Earth-orbit satellite> <-laser-- <Earth's moon> <-laser-- <L1 solar array>
<Earth> <-clearsky-burst-laser-- <Earth's moon> <-laser-- <L1 solar array>
<Earth> <-clearsky-burst-laser-- <L1 solar array>

<Earth> <- <Earth-orbit satellite>

Laser transmit antenna in space: 1 meter diameter per GW Receive: Several hundred meters across

<Earth-orbit satellite> <- <Earth's moon>

<Earth's moon> <- <Earth-Sol Lagrange-point solar array>

Targeting the energy requirement of NYC:

Power is measured in Newton-meters per second or Joules per second or Watts.
~3000 trillion BTU in 2016 = 3000 trillion btu / 365 days = 3.4E+11 btu/hr = 1.0036680479e+11 watts = 100 GW

PV energy collection

PV power stations collect more power than solar thermal power stations. They seem to average ~3 MW/km^2 (throwing out 2 ridiculous outliers).
Traditional single-junction cells have a maximum theoretical efficiency of 33.16% more. In reality it is around 18.7%.
A 65"x39" (1.64 m^2) solar panel made in 2018 produces ~320W.
About 48% of solar energy hitting the Earth reaches the surface. Perhaps optimistic, but we will divide by .48 to get energy-in-space vs on-earth.
Approximate energy absorbable by a solar panel in space: 320W / 1.64m^2 / .48% = 400W/m^2 in space
Approximate required size of a solar array "near Earth" (including l1) to power NYC: 100GW / 400W/m^s = 250 sq km

@@ Line 27: / Line 27: @@
 PV energy collection
-* [https://en.wikipedia.org/wiki/List_of_photovoltaic_power_stations PV power stations] collect more power than [https://en.wikipedia.org/wiki/List_of_solar_thermal_power_stations solar thermal power stations].  They seem to average ~6 MW/km^2.
+* [https://en.wikipedia.org/wiki/List_of_photovoltaic_power_stations PV power stations] collect more power than [https://en.wikipedia.org/wiki/List_of_solar_thermal_power_stations solar thermal power stations].  They seem to average ~3 MW/km^2 (throwing out 2 ridiculous outliers).
-* A 10 MW photovoltaic grid connected power plant commissioned at Ramagundam is one of the largest solar power plants with the site receiving a good average solar radiation of 4.97 kW h/m2/day and annual average temperature of about 27.3 degrees centigrade [ info]
+* Traditional single-junction cells have a maximum theoretical efficiency of 33.16% [https://en.wikipedia.org/wiki/Solar_cell_efficiency more].  In reality it is around [https://www.solarpowerrocks.com/solar-basics/how-much-electricity-does-a-solar-panel-produce/#top10 18.7%].
-* The final yield (Y F) of plant ranged from 1.96 to 5.07 h/d, and annual performance ratio (PR) of 86.12%. It has 17.68% CUF with annual energy generation of 15 798.192 MW h/Annum.
+* A 65"x39" (1.64 m^2) solar panel made in 2018 [https://www.solarpowerrocks.com/solar-basics/how-much-electricity-does-a-solar-panel-produce/#top10 produces ~320W].
+* About 48% of solar energy hitting the Earth reaches the surface.  Perhaps optimistic, but we will divide by .48 to get energy-in-space vs on-earth.
+* Approximate energy absorbable by a solar panel in space: 320W / 1.64m^2 / .48% = 400W/m^2 in space
+* Approximate required size of a solar array "near Earth" (including l1) to power NYC: 100GW / 400W/m^s = 250 sq km