China plans to build enormous solar array in space — and it could collect more energy in a year than 'all the oil on Earth'

Holy shit, China is really at the forefront of technology and futuristic technology nowadays.

The article is very light on details, but the numbers don't seem to check out at all. Back-of-the napkin math (assuming a square 1km × 1km solar array and total sun luminosity of 3.83e26 W):

    
1 km ^ 2 * (3.83e26 W) / (4 * π * (1 AU) ^ 2) * 1 year to TWh ≈ 11.94 TW·h

  

This is a "measly" 12 TWh of TOTAL energy delivered to the array over a year - not accounting for solar panel efficiency losses (20-24%) or the elephant in the room of transmitting this energy back to earth. For context, China alone consumed around 39 PWh (39000 TWh) of energy from fossil fuels just over the course of one year, 2023. The entire world consumed 55 PWh (55000 TWh) of oil energy in 2023 alone. It's not even comparable to the annual consumption of oil. If we consider the aforementioned factors, assuming 24% solar panel efficiency and an extremely generous 50% power transmission efficiency, we get:

    
1 km ^ 2 * (3.83e26 W) / (4 * π * (1 AU) ^ 2) * 24% * 50% ≈ 163.43 MW

  

Which is literally nothing on a national scale - it's less than a percent of the Three Gorges Dam output.

That’s a lot of microwave

headline not claimed. 1 km² as a continuous flat surface that can be pointed at sun is 250mw from commercial cells. Outside of our atmsophere, irradiance boost is only 33%. so 340mw. Geosynchronous over China will only gain up to 3 hours per day of sun. That can be a 75% boost in average daily power.

except microwave energy transmission... While a 50% efficient transmission is possible (effectively 250mw earth equivalent delivered), it needs a 100 square km receiver array. Even at 150mw per square km earth solar, is enough space for 15gw of solar.

So, it only makes sense at much larger scale, and only makes sense if denser energy costs as astronomically high as such a project. Beaming energy to other points in space, or even remotely powering a spacecraft are applications.