This concept has been around a long time; has there been a proof of concept satellite put in space yet?

Heinlein had a short story with these.

There were accidents where the beam went off kilter and scorched plenty of land and people, but it was considered an acceptable risk because the power was so cheap.

These stories come up every few years and then disappear again for the simple reason that it’s the dumbest idea in history.

Losses in transmission are about 50%. Losses due to night time are 50%. Immediately the advantages are not so obvious… losses due to weather and all other downstream effects on earth are about another 50%. Losses due to increased “weathering” in space, which is extremely hostile, are also about 50% (actually more). So in the end, flying the panel into space instead of Mohave will get you the same amount of lifetime power but cost you hundreds or thousands of times more.

Now let’s talk ground space. The article states it uses less, but that’s only on rainbow unicorn planet. Here on earth where microwave radiation is strictly controlled, the maximum power density allowed is about 100 times less than sunlight. So the land usage is 100 times as large. That is a limit controlled by the ITU among others, and they are already on record stating they will not allow any changes because doing so would wipe out space and ground based transmissions across a wide band. Consider all the arguing about low power 5G towers near airports and then multiply the power level 100 times…

This is never going to happen, everyone that’s looked at it knows this, but the space nerds keep saying it’s the next sliced milk.

Article:

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A PLAN to use satellites in Earth’s orbit to harvest the Sun’s energy from space and beam it down to Earth using microwaves could be up and running as early as 2030, with the first-of-a-kind operational system delivering power into the grid by 2040.

The concept of harvesting solar energy in space is not a new one, but until now, high launch costs and limited technology have hampered progress, said Space Energy Initiative (SEI), the organisation behind the solar farm project.

However, recent developments in reusable rockets, and more modular SPS concepts, coupled with benefits that include clean, continuous base-load energy day and night, through all seasons and weather, and with much lower land usage than conventional renewables, is helping the idea gain traction. And with the potential of each satellite to beam around 2.9 GW of net power to a receiving antenna at a fixed point on Earth, it’s a concept that has even attracted the attention of the the UK Government. In July ministers announced that £3m (US$3.6m) in funding would be allocated to space-based solar power (SBSP) projects after confirming the engineering feasibility of the concept through an independent study.

But, to harvest energy comparable in power output to a nuclear power station takes a satellite that is incredibly large. According to SEI a typical system comprises a constellation of massive, kilometre-scale satellites 38,000 km above the ground in a geostationary orbit. At this range the massive satellites should not cause any problems with light pollution, SEI said.

Each has very lightweight solar panels and a system of mirrors to concentrate sunlight onto the panels, generating around 3.4 GW of electricity on the satellite. This is converted into RF microwave radiation, with an efficiency of 85%.

To allow the microwave beam to lock onto the correct point, an encrypted pilot beam is transmitted from the ground to the satellite. The maximum beam intensity is <250 W/m2, less than a quarter of the maximum sun intensity at the equator, and the system will be designed so that it is safe in the event that humans or birds or animals strayed into the beam, said SEI.

The ground rectifying antenna or “rectenna” as it is called then converts the electromagnetic energy into direct current electricity which passes through an inverter which delivers a net 2 GW of AC power into the grid.

So what percentage of total UK electricity consumption would ten satellites provide?

I don't know what Sim City version it was. But there was a power plant that "Received concentrated microwaves beamed from satellites in space". I always think, is it really possible? Pretty neat that is kinda what is going on.

Good and all until you realize how vulnerable they are to ASATs.

Sounds like a long way away, but oh, it is only about 7 years from now. Time flies...

Was the not all the same stories back in the 50s and 60s ? Where is my flying car?

I am not a scientist. I hope someone can answer my question.

Would the energy sent from space to Earth interfere in any way with our atmosphere? Would the ozone layer be affected?

The following submission statement was provided by /u/Soupjoe5:

Article:

1

A PLAN to use satellites in Earth’s orbit to harvest the Sun’s energy from space and beam it down to Earth using microwaves could be up and running as early as 2030, with the first-of-a-kind operational system delivering power into the grid by 2040.

The concept of harvesting solar energy in space is not a new one, but until now, high launch costs and limited technology have hampered progress, said Space Energy Initiative (SEI), the organisation behind the solar farm project.

However, recent developments in reusable rockets, and more modular SPS concepts, coupled with benefits that include clean, continuous base-load energy day and night, through all seasons and weather, and with much lower land usage than conventional renewables, is helping the idea gain traction. And with the potential of each satellite to beam around 2.9 GW of net power to a receiving antenna at a fixed point on Earth, it’s a concept that has even attracted the attention of the the UK Government. In July ministers announced that £3m (US$3.6m) in funding would be allocated to space-based solar power (SBSP) projects after confirming the engineering feasibility of the concept through an independent study.

But, to harvest energy comparable in power output to a nuclear power station takes a satellite that is incredibly large. According to SEI a typical system comprises a constellation of massive, kilometre-scale satellites 38,000 km above the ground in a geostationary orbit. At this range the massive satellites should not cause any problems with light pollution, SEI said.

Each has very lightweight solar panels and a system of mirrors to concentrate sunlight onto the panels, generating around 3.4 GW of electricity on the satellite. This is converted into RF microwave radiation, with an efficiency of 85%.

To allow the microwave beam to lock onto the correct point, an encrypted pilot beam is transmitted from the ground to the satellite. The maximum beam intensity is <250 W/m2, less than a quarter of the maximum sun intensity at the equator, and the system will be designed so that it is safe in the event that humans or birds or animals strayed into the beam, said SEI.

The ground rectifying antenna or “rectenna” as it is called then converts the electromagnetic energy into direct current electricity which passes through an inverter which delivers a net 2 GW of AC power into the grid.

Please reply to OP's comment here: https://old.reddit.com/r/Futurology/comments/z4oukl/solar_farms_in_space_demo_could_be_ready_by_2030/ixrzam7/

Why not build a moonbase and production center first?

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Didn't they try something like this in a James Bond movie?

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Seeing how these are basically the saim claims regarding solar power as in the other recently posted articles...

>The concept of harvesting solar energy in space is not a new one, but until now, high launch costs and limited technology have hampered progress

High launch costs still hamper the idea. NASA concluded in a 1999 study that to even be competetive launch costs would have to come down to $200-$300/kg to GEO. That is not going to happen for a very long time, and probably not with purely chemical launch systems either. The "limited technology" argument applies to both space and terrestial arrays - only that gains in efficiency and manufdacturing capacity benefit terrestial arrays more, if anything, especially as far as decentralised power generation and storage is concerned.

>a cost modelling analysis by consultancy Frazer-Nash shows that the LCOE (levelised cost of electricity), used to compare different methods of electricity generation on a consistent basis, falls between £37 and £74/MWh, which is competitive with terrestrial renewable technologies, the organisation said.

No it is not. Even assuming the best case here this is still outperformed by utility-scale solar installations. Even wind power can outperform this. I highly doubt that this is competetive on any level if taking into account the difficulty of maintenance alone.

>[...]and with much lower land usage than conventional renewables, is helping the idea gain traction.

Also a false claim. Unless you want to sent a literal death ray in to orbit you still need about as much space on the ground for the receiving array as you would with regular solar installations - only with all the added downsides of doing things "in space":

https://dothemath.ucsd.edu/2012/03/space-based-solar-power/

>A space-based solar power system might sound very cool and futuristic, and it may seem at first blush an obvious answer to intermittency, but this comes at a big cost. Among the possibly unanticipated challenges:

>* The gain over the a good location on the ground is only a factor of 3 (2.4× in summer, 4.2× in winter at 35° latitude).

• It’s almost as hard to get energy back to the ground as it is to get the equipment into space in the first place.
• The microwave link faces problems with transmission through the atmosphere, and also flirts with roasting ducks on the wing.
• Diffraction of the downlink beam, together with energy density limits, means that very large areas of the ground still need to be dedicated to energy collection.

>Traditional solar photovoltaics in good locations can accomplish much the same for much reduced cost, and with only a few times more land than the microwave link approach would demand. The installations will be serviceable and will last longer. Batteries seem an easier way to cover storage shortcomings than launching stuff to space. I did not even address solar thermal schemes in this post, which competes well with photovoltaics and can very naturally build in storage capability.

>I am left puzzled as to why we would want to take a harder, more expensive road to solar power. I think it is just not intuitive to most how difficult and expensive space is. **And perhaps they think it’s very futuristic and cool to push our power generation out to space: it fits the preferred narrative about where we’re going. I don’t know—I’m just guessing.

>Astronomers frequently face this issue: should we build a telescope/observatory on the ground, or launch something into space? The prevailing wisdom is that if the science can be accomplished on the ground, then by golly you’d best do it that way. You’ll have the result sooner, at less expense, and with a greater chance of success.

I am not certain this would even have realistic use cases for military applications, outside of actual space-based weapon systems (the afromentioned death ray).

The math simply doesn't add up, even if you assume unrealistic optimal conditions. Looking at the involved companies it's quite clear that these are bascially hand-outs to the industry. "Space base dsolar power" isn't any more "feasible" than it has been in the decades since the idea was first envisioned, simply because the underlaying physics don't change. Either you build a death-ray in orbit or it's more attractive and straight-forward to simply build collecting arrays on earth.

Was looking for this but no one seems to notice it.

Problem of global warming is considered important at the moment, but this external solar arrays technology is transferring energy that otherwise would just go to space, it means that you are adding even more energy to the system that already struggles to cool(global warming as we have now is earth loosing cooling efficiency) that is a huge new factor that might lead to further destabilization of climate

Without running the numbers, my knee jerk reaction is this makes zero sense over generating the power here on earth.

Taking the article at face value, they claim this microwave beam will generate 250W/m^2. The RF collector on the ground would need to span an area of at least 8 million m^2 (~2000 acres) for a capacity of 2GW. The largest solar power plant in the world, Bhadla solar park, spans an area of 14000 acres with similar capacity. I’d guess antennas are much cheaper than photovoltaics too, so to a rough approximation the ground facility would be a lot more efficient than a solar plant.

The question is how much of the efficiency gains will be offset by the launch cost of the satellite. If Musk delivers on his promise of sub-$10M starship launches then space-based solar generation might actually be cost-competitive with terrestrial PV systems.

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