Using orbital solar panels and microwaves to send energy to Earth was first proposed in 1968. Since then, a few countries, including China and the US, have spent time and money pursuing the idea. The technology is appealing because orbital solar arrays represent a potentially unlimited renewable energy supply. In space, solar panels can collect energy no matter the time of day, and by using microwaves to beam the power they produce, clouds aren’t a concern either. However, even if Japan successfully deploys a set of orbital solar arrays, the tech would still be closer to science fiction than fact. That’s because producing an array that can generate 1 gigawatt of power – or about the output of one nuclear reactor – would cost about $7 billion with currently available technologies.
A big chunk of that is launch costs. And what actually is the value of 1 GW of consistent power, as opposed to variable, anyway?
Err. What happens if it drifts off course? 1GW of microwave radiation in a small area is probably lethal to everything. How small a receiver are we talking about?
FDA standard is 5mW per cm2. So .. 1GW/5mW is the area required in cm2 to avoid breaching the FDA limit. I make that 4500sqm. But am in a rush and haven’t checked orders of magnitude!
The term microwave is misleading, microwave refers to any frequency above 1GHz. Journalists looking for scare stories were fed this when Orange and 121 were building their 1.8GHz networks, it caused us no end of delays building sites and having to explain to local populations we weren’t going to be frying them.
Which brings me on to microwave ovens, they work at a frequency that excites water molecules so they obviously won’t be using microwave oven frequencies, unless they want to heat up clouds and rain drops.
Whatever energy they collect from the sun they’re going to lose a good proportion of it, probably in region of 80% generating the RF energy needed to transmit over such a distance, distance being inversely proportional to frequency, and then converting it back to grid usable energy.
Andrew again
I get 20 million sq meters – or a square 4.5 km on a side.
Pretty certain we could launch a few those rather cheaper if we really wanted to …
https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)
Gotta love : ‘no one in the U.S. government could think of any reason to put thousands of tons of payload into orbit’
@Chris: There’s a slight problem that an Orion launch is a vast EMP source which would probably fry most unhardened electronics in the same hemisphere. You’re not going to be popular when everyone’s mobile phone and tablets stop working. (Those with pacemakers will be less likely to complain.)
Would this improve the economic case for a space elevator? Run some leccy cables down the tether?
I thought that 1968 seemed a bit recent, and Wiki seems to back me up.
Don’t worry Andrew, Cutie is sure that he can keep the beam aligned.
From wiki:
“The intensity of solar irradiance including all wavelengths is the Total Solar Irradiance (TSI) and on average is the solar constant. It is equal to about 1361 W m−2 at the distance of Earth’s annual-mean orbital radius of one astronomical unit and as measured at the top of the atmosphere”
Great, so we can divide 1361 into 1,000,000,000 and we need around 75 hectares of panels, assuming perfect capture and onward transmission.
So I went and checked their source article, and they reckon an array of 400 hectares. That’s a believable amount of array.
I’m not believing the next bit about installation costs though.
Of course we could build nuclear reactors for $7 billion if all regs and harassment were eliminated.
But presumably the orbital panels’ll be subject to similar regs and harassment.
I think everyone will find that Arthur C Clarke proposed space solar power with a microwave link back in 1954 in Islands in the Sky. But whatever 🙂
Yes, it would, and dammit I’ve been reading about this stuff for 40 years now and no one at all has mentioned that as yet. No, really….
BiND is right – they won’t use h20 exciting frequencies. Still that’s some power density downlink…. And some huge array up in space. Hope there isn’t any debris flying around to hit it.
Oh.
Like duh.
The obvious reason to launch one of these is to use it as a Death Ray. Isn’t that what SDI was supposed to be about ?
Just as with other energy sources, this is great until it works. Then you find out the nasty side-effects. Coal produces smoke, leading to the infamous toxic pea souper fogs, Oil and gad produce the infamous carbin dioxide, causing global warming. Beaming down an extra few terawatts may well have some nasty effect. Maybe the concentration of energy in one area disrupts the global air ciculation patterns, maybe it causes enough warming that it’s worse than the fossil fuels it replaces.
The problem with this is that you have to put multiple 1GW solar satellites in low earth orbit to get continuous power. Geosynchronous would keep it above the same spot, but the beam losses would be huge.
An additional problem is that all frequencies below 100GHz are already allocated so atmospheric losses would be high. An upside is that beamwidth would be very narrow, reducing losses. Weather would be a significant problem as rain introduces big losses.
Investing in safe nuclear power would be a much better return on your money.
@ Bloke in Scotland
The last thing you want is to be east of a space elevator. They are far more fragile to a terrorist attack than a nuclear reactor and the failure modes are far worse with the potential for the cable to wrap itself around the earth. That sounds bad but not too bad till you consider that parts of the cable would have a diameter of hundreds of meters, it would be thousands of miles long and it would be descending from space.
Kim Stanley Robinson had a Mars elevator dropping in his Mars trilogy. Geostationary orbits about 23,000 miles so it’d nearly wrap the equator. It’s starts coming down quite slowly but preservation of angular momentum. The top will come down through the atmosphere at I make it 8.4 miles per second. So depending on where you tether your elevator, 2000 miles west of it’s gonna get a helluva slap. Anyone want to nominate a country on the equator?
Actually, come to think of it, one doesn’t need to have a geostationary orbit in the orbital plane. The limit’s the cable drag from the atmosphere at the pole ends of the orbit. Not much because hardly any of it’s in the lower atmosphere & the relative velocity’s low. So you’re free to chose pretty well anywhere you like south of say Westminster.
hmmm… What’s the upkeep on several square miles of metal bits on an artificial island in salt spray ?
I know the ESA proposal from the early 80’s was binned exactly because the upkeep and running costs on an island on the Dogger Bank would make the whole thing extremely uneconomical at the time.
And honestly… stop with the damned space elevators…
– The physics don’t work.
– We. do. not. have. Unobtanium. for. the. stalk. and. other. working. parts.
– The thrust solutions needed to keep the damned things stable in the proposed setups would make our gravity well a non-issue, rendering them obsolete from the start even if we could build them.
All energy dissipates to heat. So capturing energy from space and beaming it back to earth will contribute to Global Heating (TM)
Treble turnip salads all round and be grateful, peasants!
Don’t go bringing the power down to earth, use the power to build things in space. What if we had some massive solar collectors in space, and a unit to convert that to hydrocarbons? Basically run by robots. Then we send up a rocket with a load of empty storage, and it gets filled up with those hydrocarbons and sent back to earth?
Sure, it’s going to use fuel going up there, but you can bring more back.
Then maybe, you start getting clever. Mine asteroids for materials, build the return vessel in space, send it home. No need to fly a thing up, it just drops into the atmosphere. Perhaps something collects it. Or hydrogen balloons to slow descent.
You’d need some mad lunatic like Elon behind it, but it feels like it’s theoretically possible. It also leads to our colonisation of space. Not wanky scientists in the ISS goofing around with tennis balls, but the equivalent of oil rigs in space. You’re going to need a few guys to oversee the robots.
You’d need to carry the carbon and hydrogen up to orbit BoM4, unless you could get it from the moon. Of course there’s plenty on Jupiter, but that’s a bit far away for a first try.
It’s why I always like just building the nukes and extracting the hydrogen and carbon from water and CO2 here on earth. The only tech that’s not off-the-shelf is the CO2 extraction from the atmosphere. But this’d certainly cost more than just pumping the stuff out of oil wells.
Another, ever so clever but ruinously expensive solution to a non-problem (well, a solution to the problems caused by the political response to a non-problem).
The empirical evidence from ice cores and other proxies show:
1. The pre-industrial era considered to be the ‘safe’ baseline for the planet was the coldest period in the last 10,000 years. For most of the time prior, temperatures were 2 – 3 degrees warmer. It’s no suprise the temperature is going up.
2. In the last million years, every time the earth has experienced a warming event, CO2 goes up after the rise in temperature, never before. The tail is not wagging the dog.
Addolff
Will you stop it with these Hate Facts ?
“ In the last million years, every time the earth has experienced a warming event, CO2 goes up after the rise in temperature, never before. The tail is not wagging the dog.”
In the early days of C4, must have been ‘84 or ‘85 because I as in UK, they had a very good science program that followed some some scientists doing ice core drilling and they showed this phenomenon in a number of samples. I’ve searched for that program a few times over the years but it seems to have been memory holed for some reason.
BiND
It being C4, they were probably trying to disprove Wobal Glorming becausr Thatcher in those days pretended to believe in it.
Boganboy,
Yeah, that’s an epically stupid plan isn’t it, because of the getting water up there. I may have posted this when I was very, very drunk.
@Arthur the Cat
Whilst I may not have been entirely serious (I’d probably go nuclear but there are other reasons we might want to lift 8m tonnes into orbit a time or two!) its been calculated the EMP footprint of an Orion is a couple of hundred miles across and not terribly intense for much of that. Plenty of safe places to do that and the launch pad will be a pretty unfriendly place anyway. A permanent downward beam of 1ghz near enough to populations to prevent further transmission loss might be more of an issue depending.
As to the space elevator yeah no can do but if you could and wanted to bring it down you have to blow up your unobtainium cable in the middle, is not actually tethered.
There are some interesting ideas about rotating platforms on the vertical axis to give a boost from low to high orbit and similar but I’ve never seen a detailed write up. Tethers do play a part there as both structural and conductors.
Can we try to remember what problem we are trying to solve here before we go off into 1940’s science fiction?
The problem is not that we don’t have plenty of power sources but that we have been led to believe, falsely, that CO2 is a threat when it really really isn’t. It would be solved with merely a liberal application of proof that sceptics are correct.
BiND @ 7.06. Don’t know if this is part of the programme…..: https://www.youtube.com/watch?v=WE0zHZPQJzA
It appears as if this bloke has been ‘re-educated’ in recent times…….
There are some interesting ideas about rotating platforms on the vertical axis to give a boost from low to high orbit and similar
The rotational axis would be horizontal, not vertical. And it’s not a full length tether to geostationary. Much shorter. The tether rotates so the bottom end enters the upper atmosphere. At its closest point to the surface, it’s stationary relative to the earth rotating under it. So a craft can rendezvous with it & hook on. At the top end it can release, having gained orbital velocity. Conservation of angular momentum is preserved by having traffic going in both directions. Rather than having a heatshield for atmospheric re-entry, a craft hooks on at the top & it looses velocity on its way down to being stationary at the bottom. That provides the energy for a craft going in the opposite direction.
A refinement would be to have rotating tethers like this throughout the solar system. They impart the delta-V to take you wherever you want to go & a rotating tether at the destination slows you. down again. And provided there’s equal mass travelling in both directions, the energy is free. An Earth>Mars voyage decelerating at Mars provides the energy to accelerate a Mars>Earth voyage. Since the tether itself would have considerable mass the energy from any traffic balance discrepancies could be stored in the tether without much changing its overall angular momentum. It’s only necessary to have a “balance of trade” over time.
Oh & Mars then doesn’t have to be six months away. You could do the trip in days. The velocities are proportional to the length of the tether.
But rhoda I love my copies of 1940 science fiction. Every crumbly book with the pages coming out and the covers stuck together with sticky tape. I’d throw a real tantrum if it was all chucked away.
But as for the climate change, I have to agree with you. When they say ‘We’ll all die if we don’t get net zero by—–‘ I think 2030 is the latest date. And then insist on shutting down all the nukes.
Even someone whose knowledge of science comes from 1940’s scifi can’t really take it seriously.
Were people actually writing SciFi in the 40s? Very few, I’d imagine. Most of it’s cowboys & indians or war stories with added space ships. Even Azimov wrote very little. Mostly he depends on unexplained gizmos do what the plot requires. Clarke uses geostationary orbits in the 50’s but the physics was established.
Why the cognoscenti tend to use the other SF – speculative fiction – to distance themselves from Star Wars.
This was actually a thing in an early incarnation of sim city. Including the satellite incinerating part of the city when it drifted off course.
BinD 07:06
i seem to remember that C4 did a great science show Equinox and i seem to remember what you are talking about.
Bit of a google and
Equinox – The Greenhouse Conspiracy and got a link https://licensing.screenocean.com/record/133828
not re watched but this might be it.
Boganboy,
“But as for the climate change, I have to agree with you. When they say ‘We’ll all die if we don’t get net zero by—–‘ I think 2030 is the latest date. And then insist on shutting down all the nukes.”
The thing that really broke me with climate change is “climate emergency”. Because it just isn’t an emergency. That’s literally what the science says. It’s a gradual problem. Something like 0.2 degrees per decade. Doesn’t really matter that much if we do nothing for 20 years.
The whole thing reminded me of dealing with cheap salesmen, and how, when they don’t have you, they use various tactics to try and sell you on the emotional impact of not having XYZ product right now. Sometimes as far as almost yelling at you on a Friday, and you know that’s their end of period quota deadline.
I think a lot of people in the climate change industry know that it isn’t going to happen, and that people are going to figure it out. Like they keep promising various parts of Gotterdamarung like no ice in the arctic, no snow in London. famine, plague, frogs falling from the sky, the dead rising from their graves, the oceans consuming the cities and none of it is happening. They’re getting desperate to sell it before the world calls bullshit on it.
‘Were people actually writing SciFi in the 40s?’
Well bis, I’d argue that magic as a plot device had become a trifle formalised. So ‘science’ was a good way to introduce that unexplained gizmo. Eg, a robot rather than a demon.
BoM4. I hope you’re right about it all dying and this is the last desperate push.
But there is that wonderful thing called democracy. I really liked the way that, when the electricity could actually have been cut off, the Germans reopened a coal mine. Fortunately the pollies seem to worry more about their power and status than the possibility of the world ending.
Heinlein was writing SF in 1940 and getting published in Astounding by John W. Campbell. Yes of course there were Space Operas which could have been set in a different genre. Oh, EE Doc Smith was the doyen of them and they contained a lot of technology speculation too.
And never forget Wells and Verne.
I really liked the way that, when the electricity could actually have been cut off, the Germans reopened a coal mine.
A fellow spectator at Monday’s Middlesex T20 match was wearing a T-shirt sporting a stylised sun and the legend “Atomkraft? Ja Bitte”.
Or alternately, The Great Global Warming Swindle.
https://www.youtube.com/watch?v=oYhCQv5tNsQ
Must admit I always liked the cover pictures of the girls in skimpy clothes and a bubble helmet, rhoda.
Real space suits were a bit of a disappointment.
@Philip
You really don’t need to worry about the extra heating the Earth would receive. This planet already gets 25MW of solar insolation for each human living on it.
Oh, I remember Equinox fondly. Very well made and well presented. I remember a “Origins of the Universe” episode, narrated by Peter Jones in his “HHGTTG” voice, which matched the content perfectly!
@ John Galt
Worth remembering how many “science fiction”writers have jumped on the Great Global Warming Bandwagon. Not Larry Niven of course, who wrote the Descent of Anansi distopia.