this post was submitted on 31 Mar 2025
2 points (100.0% liked)

Technology

37410 readers
154 users here now

This is the official technology community of Lemmy.ml for all news related to creation and use of technology, and to facilitate civil, meaningful discussion around it.


Ask in DM before posting product reviews or ads. All such posts otherwise are subject to removal.


Rules:

1: All Lemmy rules apply

2: Do not post low effort posts

3: NEVER post naziped*gore stuff

4: Always post article URLs or their archived version URLs as sources, NOT screenshots. Help the blind users.

5: personal rants of Big Tech CEOs like Elon Musk are unwelcome (does not include posts about their companies affecting wide range of people)

6: no advertisement posts unless verified as legitimate and non-exploitative/non-consumerist

7: crypto related posts, unless essential, are disallowed

founded 6 years ago
MODERATORS
top 11 comments
sorted by: hot top controversial new old
[–] [email protected] 1 points 2 days ago

headline not claimed. 1 km^2^ 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.

[–] [email protected] 1 points 2 days ago

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

[–] [email protected] 1 points 2 days ago* (last edited 2 days ago)

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.

[–] [email protected] 1 points 2 days ago (1 children)

I was hoping the article would explain how they planned to transmit the energy in a useful way. It says beaming back my microwave, but I have no idea how that works or if it has a good scale potential. Guessing they’re targeted at some surface that vibrates or heats up and that geberates the power on the terrestrial side of the equation?

[–] [email protected] 1 points 2 days ago (1 children)
[–] [email protected] 0 points 2 days ago (1 children)

That is very helpful. Now I want to know silly stuff like, what happens if you fly through the beam, and could you in theory reaim the array towards a completely different receiver plant, and be able to shift power around as needed (albeit very slowly)

[–] [email protected] 1 points 2 days ago

The intensity of the waves is very low in absolute terms, so they're not harmful.

Microwave beaming—using radio-frequency phased array antennas with intensity levels below mid-day sun-light—is deemed less harmful, with potential physiological effects manageable through thermoregulation.

https://restservice.epri.com/publicdownload/000000003002029069/0/Product

[–] [email protected] 1 points 2 days ago (1 children)

Lately i heard so many amazing things that china will do. I almost now want to live in china and not usa anymore. They got me convinced.

[–] [email protected] 1 points 2 days ago

I've been slowly learning Putonghua for the past two years here. At this point, I just can't see how anything gets better in the west in the near term, meanwhile life in China is improving by leaps and bounds each and every year.

[–] [email protected] 0 points 2 days ago (1 children)

Giant microwave space laser is totally not a death ray?

[–] [email protected] 1 points 2 days ago

about as much of a death ray as the sun on a mild afternoon https://restservice.epri.com/publicdownload/000000003002029069/0/Product