back to article Can solar power be beamed down from space? Yes. Is it commercially viable? Not yet

A year after the launch of the Space Solar Power Demonstrator (SSPD-1), the California Institute of Technology (Caltech) is revealing the highs and lows of the mission. SSPD-1 was the first space-borne prototype from Caltech's Space Solar Power Project (SSPP) and was designed to show that taking solar power gathered in orbit …

  1. pdh

    Alternative uses

    I remember my thesis advisor talking about this possibility decades ago. He said that weaponization was a real concern: if you can beam a huge amount of energy from space to a ground station via microwaves, then you could probably also re-target that beam to other locations outside of your borders; leading to an arms race as soon as any one nation started work on such a system.

    1. Anonymous Coward
      Anonymous Coward

      Re: Alternative uses

      It wouldn't matter if you did that, the power density per m² would be too low to be harmful.

      1. Jellied Eel Silver badge

        Re: Alternative uses

        It wouldn't matter if you did that, the power density per m² would be too low to be harmful.

        So just crank up the power until it is harmful. You could even spin this as carbon reduction, if you could use a microwave to sterilise large swaths of land, and kill all the soil bacteria.

        But yet another article demonstrating why the Green Blob loves other people's money. Whether or not it's economically viable really means whether it can suck subsidies out of the economy via regulatory capture. Case in point here-

        https://www.theguardian.com/business/2024/jan/16/drax-gets-go-ahead-for-carbon-capture-project-at-estimated-40bn-cost-to-bill-payers

        The project could add about £1.7bn to energy bills every year if the company acts on plans to fit all four of its biomass units with carbon capture technology, or a total of more than £43bn, according to Ember, a climate thinktank.

        In addition, the government is expected within days to extend a lucrative bill-payer-backed subsidy scheme that last year paid Drax more than £600m to burn trees for electricity until the end of the decade.

        And it will achieve nothing wrt lowering CO2 levels. Oh to be wealthy enough to pay for a judicial review into this insanity.

        1. Androgynous Cupboard Silver badge

          Re: Alternative uses

          The "green blob" (waves) doesn't even remotely support CCS in general and Drax in particular. Thats 100% Tory pork you're criticising.

          1. Jellied Eel Silver badge

            Re: Alternative uses

            The "green blob" (waves) doesn't even remotely support CCS

            The 'green blob' is the money and lobbying behind scams like these, not the useful idiots gluing themselves to roads.

            1. Androgynous Cupboard Silver badge

              Re: Alternative uses

              "When I use a word," Jellied Eel said in rather a scornful tone, "it means just what I choose it to mean — neither more nor less."

              1. Jellied Eel Silver badge

                Re: Alternative uses

                "When I use a word," Jellied Eel said in rather a scornful tone,

                Not really. The 'Green Blob' has always referred to the big businesses, wannabe big businesses and lobbyists who provide the misinformation. It has been ever thus. One of the first moves was when an astroturfing outfit created 'RealClimate' to help Al Gore promote his Inconvenient Truths and support his VC ambitions.

        2. Anonymous Coward
          Anonymous Coward

          What about hallucinogenic mushrooms?

          > You could even spin this as carbon reduction, if you could use a microwave to sterilise large swaths of land, and kill all the soil bacteria.

          Not sure what you're smoking, but it's strong. You remind me of that US student I had some time ago who thought he needed to kill all his gut bacteria to be healthy.

          1. Jellied Eel Silver badge

            Re: What about hallucinogenic mushrooms?

            Not sure what you're smoking, but it's strong. You remind me of that US student I had some time ago who thought he needed to kill all his gut bacteria to be healthy.

            It's called reality, biology, and understanding the biosphere you're hiding from-

            https://www.nature.com/articles/ismej200858

            The consequences of increased carbon flux from roots to soil for microbial communities and carbon exchange are difficult to predict, because they will vary substantially with factors such as plant identity, soil food web interactions, soil fertility and a range of other ecosystem properties

            There's even a handy picture for you to look at showing the carbon cycle. Oh, and also-

            While the increase in O2 availability that accompanies drought promotes organic matter decomposition in wetlands and peatlands, thereby increasing CO2 release, opposing effects occur for methanogenic pathways, in that methane emissions are reduced.

            We're busy increasing CO2 and methane production by 'restoring wetlands' as part of an EU diktat. This will also increase the prospects of malaria and other mosquito vectored illnesses. But ecofreaks generally have a very poor understanding of both history and science. The 'ague', aka malaria was common around London, until we drained the swamps..

            So to prevent this potentially catastrophic release of CO2 and CH4, simply microwave the soil to sterilise it. Soil bacteria do, after all release far more CO2 and CH4 than humans do. That's life, and you can witness the Earth breathing in the famous Keeling curve. Any human effects are far harder to spot because they're pretty insignificant really..

            1. Anonymous Coward
              Anonymous Coward

              Re: What about hallucinogenic mushrooms?

              You're nuts. Tell me how you sterilize soils, yet keep photosynthesis and organic matter storage running (not mentioning albedo and climate issues of desertic areas). Your comprehension of biological ecosystems and trophic networks is as abysmal as that of their counterpart in the economic dimension. A 12 year old spews less nonsense in one full year than you do here in one single day.

              1. Jellied Eel Silver badge

                Re: What about hallucinogenic mushrooms?

                You're nuts. Tell me how you sterilize soils, yet keep photosynthesis and organic matter storage running (not mentioning albedo and climate issues of desertic areas).

                Do I really have to start adding /sarc tags? The clue should have been in the word 'sterilise'. One way to sterilise soil is to microwave it. This may not be a good idea for the reasons you've just realised. Adding an additional 100W/m^2 is going to have an obvious effect on soils, and anything living/growing in or on it, hence why most of these proposals suggest desert areas for their antena arrays. But again this is normal for climate 'science', eg windmills have a drying effect downwind due to vertical mixing and vortex creation. Obviously this mostly affects the area downwind, and sucks if you happen to be trying to farm that.

                Your comprehension of biological ecosystems and trophic networks..

                Earlier you mentioned you had a 'student'. I really hope you're not an educator. Then again, the current education system is why we have so many kids with a very strange belief system.

                1. Anonymous Coward
                  Anonymous Coward

                  Re: What about hallucinogenic mushrooms?

                  "Do I really have to start adding /sarc tags?"

                  Actually yes. It could be useful when people who write stupid comments 90% of the time happen to also write stupid comments intentionally the remaining 10% of the time.

          2. Anonymous Coward
            Anonymous Coward

            Re: What about hallucinogenic mushrooms?

            Now that’s just silly. You eat magic mushrooms, not smoke them.

        3. Jimmy2Cows Silver badge

          Re: So just crank up the power until it is harmful.

          And how exactly do you "just crank up the power" with a fixed number of satellites, in fixed orbits, with constant insolation, constant power transmission and constant conversion efficiencies?

          Might as well have said "just crank up the sun".

          1. Diogenes8080

            Re: So just crank up the power until it is harmful.

            The satellites presumably have rockets for occasional orbital correction. Use those to aim a number of satellites at the same spot. Instant barbie!

          2. Michael Wojcik Silver badge

            Re: So just crank up the power until it is harmful.

            Not to mention the perhaps subtle fact that we (that is, humanity) have a whole bunch of non-space-based weapons, which we have been quite successful at using to kill one another. It's not clear why a Big Space Maser would make all that much difference.

            Sure, you can target any spot in its orbital path without moving military hardware. You can do the same with an ICBM.

            Orbital power delivery doesn't make a particularly great weapon. It's limited in where it can target. It's not flexible. It's expensive. It's fragile. Really, an orbital power system is more likely to be a target.

      2. Wellyboot Silver badge

        Re: Alternative uses

        It depends how the technology matures, case example from history.

        That trick of yours with the stick and some twine bending it is interesting...but not much use.

        FFWD (quite a long time t.b.f.)

        "No Harold, don't watch, get under your shield!"

      3. Filippo Silver badge

        Re: Alternative uses

        >It wouldn't matter if you did that, the power density per m² would be too low to be harmful.

        I don't think so? It doesn't take much more than regular sunlight to be harmful. But let's assume you're right.

        If you were actually deploying this at any useful scale, then you would have dozens of similar systems. Turn them all on the same spot. Done! (As in, cooked).

        1. Anonymous Coward
          Anonymous Coward

          Re: Alternative uses

          But let's assume you're right

          You don't need to assume anything. Just read the articles linked to, especially the ones that say that power density at the centre of the beam is only a quarter of that from the midday sun at the equator.

          1. Lurko

            Re: Alternative uses

            In which case why are they bothering, as there's stuff all value in that. The answer is of course that this is simply early stage R&D.

            To do anything at production scale is going to involve much higher power density, and if they can't scale up, then this research is heading nowhere.

            1. DS999 Silver badge

              Re: Alternative uses

              The benefit to 1/4 of the power of noonday sun at the center of the beam is that it could be operational 24 hours a day 365 days a year, regardless of day/night or cloud cover (there may be some limits the amount of clouds/rain depending on the wavelength being beamed at the Earth)

              I still think it is folly because even today's less than ideal battery technology is likely more cost effective for providing 24x7 power than any "beam power to earth" scheme. And with tomorrow's battery technology - which will arrive long before any large scale power beaming project could be producing power at commercial levels - it won't even be a contest. There's no point to researching power beaming, that's a sci fi dream with that will never see the light of day as it were.

              1. Jellied Eel Silver badge

                Re: Alternative uses

                The benefit to 1/4 of the power of noonday sun at the center of the beam is that it could be operational 24 hours a day 365 days a year, regardless of day/night or cloud cover (there may be some limits the amount of clouds/rain depending on the wavelength being beamed at the Earth)

                Not really, or not without spending a collosal amount of money. Problem being we're spinning, so if the idea is to convert solar energy in space, and then beam that to the ground.. The collector satellites are going to be in darkness for some period. Which then gets into interesting orbital challenges, and beaming power in space from light to dark side. Plus the slight snag with the inverse square law and not frying any satellites that just happen to be crossing your beam path. A similar challenge to some terrestrial solar plants, but the 'streamers' you're zapping aren't birds, but maybe a bunch of expensive Starlink satellites.

                1. John Robson Silver badge

                  Re: Alternative uses

                  "The collector satellites are going to be in darkness for some period."

                  Have you considered what that period might be?

                2. DS999 Silver badge

                  Re: Alternative uses

                  The collector satellites are going to be in darkness for some period

                  A satellite in geosynchronous orbit is in shadow a little over an hour per day, but nothing says there can only be one satellite per ground station. You might not invest in a second satellite if you have only one ground station, but if you have a number of them across the US for example you could have one additional satellite across that same arc and adjust the beams as one falls into shadow so all stations are powered 24x7. Though maybe you don't worry about it, since the hour of outage comes at local midnight when you have off peak demand.

          2. Chet Mannly

            Re: Alternative uses

            I assume that is just the test system, and deliberately calibrated that way to avoid the tin foil hatters. I mean those same solar panels deployed on the earth would generate 4x the amount of power if that's the case.

            For this to be a viable power generation and delivery method useful to society it will have to be many, many, multiples of solar power, probably orders of magnitude higher to make any difference.

            1. Jellied Eel Silver badge

              Re: Alternative uses

              For this to be a viable power generation and delivery method useful to society it will have to be many, many, multiples of solar power, probably orders of magnitude higher to make any difference.

              I think this is why the effort is to an extent futile, ie unless it's to weaponise it. Otherwise to keep it safe(ish), the power density is going to be so low that it'll probably need a massive receiver array to do any useful work.. And then there's the cost.

              1. cyberdemon Silver badge

                Re: Alternative uses

                "steering" of storm systems? (for good or evil)

                1. Jellied Eel Silver badge

                  Re: Alternative uses

                  "steering" of storm systems? (for good or evil)

                  Probably be easier to use them as vortex generators. Then ring them with windmills and spin that lot! Simple really, and what could possibly go wrong?

                  Meanwhile, anyone who's ever worked with microwaves know they get humble H2O really excited. Launching all that power into all that atmospheric water vapor and again, what can possibly go wrong?

                  1. ldo Silver badge

                    Re: “vortex generators”

                    There are certain trigger words that I have picked up from reading and viewing too much cheap sci-fi in my younger days.

                    “Vortex” is one of them. ♐

                    1. Jellied Eel Silver badge

                      Re: “vortex generators”

                      There are certain trigger words that I have picked up from reading and viewing too much cheap sci-fi in my younger days

                      Heh, I still read a lot of that. Can't remember which one used vortex generators as a plot device, but the idea kinda stuck with me.. Especially as it's something that's already 'technically feasible'. I've made flame vortex generators before, and they're pretty. Microwaving soil was used in Peter F. Hamilton's Fallen Dragon though, where MASERS got used as part of their 'asset realisation' programme. I like that book for it's takes on interstellar commerce and capitalism.

                      1. Eclectic Man Silver badge

                        Re: “vortex generators” 'Cheap' science fiction

                        Try Roy Lewis's 'The evolution man', I don't think the word 'vortex' appears in it, but it is an interesting read.

                        I got a copy in really good condition from Oxfam books, a snip at £17.98

            2. the Jim bloke

              Re: Alternative uses

              It would definitely improve the credibility of tin foil hats..

              The energy cost of construction is orders of magnitude higher than its output - so dumb idea.

              Change the construction costs, then revisit the feasibility.

              Otherwise, find another reason why you want to be able to dump supposedly large amounts of energy anywhere on the planet

              1. Jellied Eel Silver badge

                Re: Alternative uses

                Otherwise, find another reason why you want to be able to dump supposedly large amounts of energy anywhere on the planet

                It's the usual story. Money. Either in grant form, or a few billion to set up a pilot problem. But it all makes perfect sense. We're having a bit of a climate emergency due to a teeny bit of additional energy in our atmosphere due to an extra 100ppmv of CO2. So obviously the solution is to add more energy, where most of it will be absorbed by the far more abundant H2O. Unless they somehow tune their microwaves to avoid H2O's spectrum, in which case it'll mess with the photochemistry of some other species.

                This stuff is a prime example of just because we can, it doesn't mean we should.

              2. CountCadaver Silver badge

                Re: Alternative uses

                Someone at Northrop Grumman has played command and conquer and thinks an ion cannon would be a battlefield game changer? No 3-15 minute warning, no just sudden and without warning death from above. No radiation, no debris, no possibility of interception.

                Perhaps escape from LA was more their thing and the potential for sending a rival nation back to the dark ages appeals?

              3. MrDamage

                Re: Alternative uses

                Because geothermal, solar, wave and wind are limited depending on locality, and people are antsy about nuclear and fossil fuels.

                We want clean energy, we have to start looking up.

            3. Jimmy2Cows Silver badge

              Re: solar panels deployed on the earth would generate 4x the amount of power

              At the equator, at noon, on a cloudless day. Which really isn't a high proportion of a 24 hour period. Plus those panels would have to be at the equator, with power lines distributing that to the rest of the world. Naive to think that's actually a geopolitically workable solution.

              The point with SBSP is that efficiency doesn't really matter. There's near-permanent insolation in high orbit, and if we need more power we just have to bung up some more satellites and build some more rectennas down on Earth. The transmission frequencies aren't blocked by clouds or atmospheric water vapour, and power generation is constant, day and night.

              Rectennas that can be hung above farmland, woodland, wetland etc. Because the area the cover is almost entirely open to the sky, and you can continue growing stuff underneath. Levels of microwave power will never be high enough to cause problems.

              1. Jellied Eel Silver badge

                Re: solar panels deployed on the earth would generate 4x the amount of power

                The point with SBSP is that efficiency doesn't really matter. There's near-permanent insolation in high orbit, and if we need more power we just have to bung up some more satellites and build some more rectennas down on Earth. The transmission frequencies aren't blocked by clouds or atmospheric water vapour, and power generation is constant, day and night.

                Efficiency always matters. So a crude view would be you're taking 1360W/m^2 at TOA and converting it into 100W/m^2 at the surface. This isn't efficient, but as the input is 'free', who cares, right? Bigger issue is the cost of providing some useful amount of electricity at a commercial price. Wiki has an article here-

                https://en.wikipedia.org/wiki/Space-based_solar_power#Launch_costs

                To give an idea of the scale of the problem, assuming a solar panel mass of 20 kg per kilowatt (without considering the mass of the supporting structure, antenna, or any significant mass reduction of any focusing mirrors) a 4 GW power station would weigh about 80,000 metric tons

                But that cost may fall as launch costs (ie Starship) or lighter transmitter arrays are developed. But-

                For comparison, the direct cost of a new coal[75] or nuclear power plant ranges from $3 billion to $6 billion per GW (not including the full cost to the environment from CO2 emissions or storage of spent nuclear fuel, respectively)

                And those costs are (or could also be) falling. There's a lot of creative marketing around 'levelised' costs to favour pet technologies to make 'renewables' look economically attractive. But without subsidies, nobody would buy the product, if alternatives could generate electricty 'cleanly', reliably and predictably at a far lower cost per MWh. Then there's the cost of the terrestrial infrastructure, ie land, rectenna and safety costs. Because the power levels are way above safe levels, the reciever arrays would have to be remote, which means adding the transmission costs for grid tie-ins as well. Obviously if an SBS system can deliver only tens or hundreds of MW, the costs need to be spread over those MW, and the MWh sell price is likely to be even more expensive than offshore wind.

                Then there's land use efficiency. The US has a lot of unused Federal land that could be converted into power reserves, but the UK does not. But then how much energy per km^2 could be generated? Nuclear is very energy efficient in land use terms, ie a 500MW SMR can comfortably occupy a small part of a submarine, or building.

                Rectennas that can be hung above farmland, woodland, wetland etc. Because the area the cover is almost entirely open to the sky, and you can continue growing stuff underneath. Levels of microwave power will never be high enough to cause problems.

                Those are big assumptions. But 'renewables' proponents seem to be very much anti-wildlife. So farmers already know that one way to keep birds off crops is to make a 'rectenna' above them. Birds and bats will fly into the wires and may get killed or injured. This may be a problem if the animals are pollinators or insectivores. Plus there's the potential effects on insects, or the plants themselves, or even wetlands because the microwave energy will be absorbed. But the current safety measures seem to be making it remote, so power levels are currently unsafe to farm in, or have a woodland picnic under the slowly browning and dieing forest.

      4. Lurko

        Re: Alternative uses

        "It wouldn't matter if you did that, the power density per m² would be too low to be harmful."

        For this to be viable (cheaper than terrestrial solar power, say) the ground receiver needs to be operating at MUCH higher power densities than solar insolation, regardless of the wavelengths being used. As the car-melting tower block in London demonstrated, it's entirely feasible to cause damage at relatively low multiples of terrestrial insolation even at highish latitudes. To be both economic and of big enough scale to make any difference (as opposed to trials) we're talking megawatts or even gigawatts of power, and all focused into fairly compact sites. This has far, far better prospects as a death ray than as a useful, safe power source. And I'm sure the agencies with vast research budgets for killing people will be thinking, "Hey! That's cool, we could find a use for that!"

        Addendum: As a certified old git, I will of course assert the The Reg isn't what it used to be, on account of failing to mention the Icarus weapon from the dismal 2002 James Bond film, Die Another Day.

        1. Anonymous Coward
          Anonymous Coward

          Re: Alternative uses

          the ground receiver needs to be operating at MUCH higher power densities than solar insolation

          FFS read the linked papers. 25% of midday insolation at the equator.

          1. Lurko

            Re: Alternative uses

            FFS anonymous clown, my comments are about the potential for future use. This is a research project, to prove a few concepts to see if it can be taken further, and what these papers refer to is a demonstration that implies it might be feasible. But at current scale this doesn't answer any problem that humanity has.

          2. Jellied Eel Silver badge

            Re: Alternative uses

            FFS read the linked papers. 25% of midday insolation at the equator.

            Or just think about what you've read. So insolation at the equator's rougly 400W/m^2. Which is handy, because then your 25% means you're boosting insolation at whatever latitude by an extra 100W/m^2. So the beam spot in the UK would end up with insolation roughly equivalent of N.Africa. It's generally.. a bit warmer there, no?

            1. Jimmy2Cows Silver badge

              Re: Alternative uses

              It's not total insolation, which is spread across a wide bandwidth and absorbed by lots of things, hence they heat up when out in the sun.

              It's microwave power. Specifically tuned microwave power, which is mostly not absorbed by the atmosphere it's passing through (otherwise it just cannot work), and is absorbed by the receiving rectenna it's targeting (again otherwise it cannot work). Incident heating from the beam is minimal.

              It wouldn't be like standing in a giant microwave where all your water molecules are being jostled until you boil.

              The beam frequency is chosen to specifically not be absorbed by water molecules.

              1. Jellied Eel Silver badge

                Re: Alternative uses

                The beam frequency is chosen to specifically not be absorbed by water molecules.

                Or any molecule in our atmosphere. But then you're also beaming that at the surface, and that surface is going to absorb the additional energy. And then warm, and radiate at a different wavelength that probably will be absorbed by H2O, CO2 etc.

                1. Jimmy2Cows Silver badge

                  Re: Alternative uses

                  You're clutching at straws, seemingly without an understanding of the actual physics involved.

                  Dimensions and spacing of the rectenna wires are chosenen to harmonise with the specific microwave wavelength, to absorb it. Similar in concept to the grid of holes in a microwave door; visible light can pass through it, but microwave raditation cannot.

                  Wavelength of SBSP transmission is specially chosen. There's a wide band of microwave wavelengths / frequencies. It takes very specific frequencies to interact with molecules to excite them and cause heating.

                  1. Jellied Eel Silver badge

                    Re: Alternative uses

                    You're clutching at straws, seemingly without an understanding of the actual physics involved.

                    I did design microwave transmitter systems many moons ago, but it isn't my specialty. But actual physics-

                    https://en.wikipedia.org/wiki/Microwave#/media/File:Atmospheric_Microwave_Transmittance_at_Mauna_Kea_(simulated).svg

                    So unless you're transmitting at a very narrow waveband, the atmosphere is going to absorb some energy. Same with the surface, ie having a very precise rectenna array that doesn't move or get damaged. Again it's all well know, has been studied and theorised for decades and is pretty pointless when building reactors would be faster, cheaper, safer and a lot more efficient.

        2. Jimmy2Cows Silver badge

          Re: the ground receiver needs to be operating at MUCH higher power densities than solar insolation

          No, it doesn't.

          The recieving rectennas just need to cover a large area. But since they're basically just cheap wire grids you can string them up pretty much anywhere. The relatively wide spacing between the wires means most of the land under the rectenna is open to the sky and can still be used for everything it's used for now. Can't so that with solar panels.

          The transmission system can't actually focus the power spot tightly enough to be dangerous, which is one of it's attractions. Useful for power generation, not useful as a weapon.

        3. CountCadaver Silver badge

          Re: Alternative uses

          Die another day was an entirely passable movie, unlike the horror that was never say never again, followed closely by any of the roger Moore movies *shudder*.

          At least brosnan had the delectable Halle Berry in a bikini to improve the movie.

        4. Grinning Bandicoot

          Re: Alternative uses

          Also missed were all the articles by Jerry Pournelle. They seemed to everywhere back in the 70s and 80s.

          1. Jellied Eel Silver badge

            Re: Alternative uses

            Also missed were all the articles by Jerry Pournelle.

            I miss the articles he used to write in Byte. And Byte in general. But at least we have El Reg.

    2. mevets

      Re: Alternative uses

      There were a series of documentaries about this in the 70s.

      One prototype was setup in the Nevada desert outside Las Vegas; another in Thailand.

      In both cases, UK terrorists sabotaged the prototypes, presumably to keep North Sea oil viable.

      I think the chief scientist on one of those projects ended up shilling for Dodge/Chrysler.

    3. Sudosu Bronze badge

      Re: Alternative uses

      See the 1980 movie Death Ray 2000...

    4. aerogems Silver badge
      Flame

      Re: Alternative uses

      There are terrestrial solar arrays already that work on a very similar principle. You have a set of mirrors which all reflect the sunlight back onto a central point, and that is used to generate power. There have been cases where a tiny miscalibration in one of the mirrors caused the power generating mechanism in the middle to catch on fire.

      1. vtcodger Silver badge

        Re: Alternative uses

        "There are terrestrial solar arrays ..."

        That would be the Ivanpah (California) bird burner. https://en.wikipedia.org/wiki/Ivanpah_Solar_Power_Facility The facility used 13sq km of mirrors to heat 3 boilers to 560C. It also used large amounts of natural gas (4 times the original plan) to start up generation in the morning when sun angles are low. And it fried an estimated 6000 birds every year. the 2.2B USD faciility did generate well over 800Mwh of electricity in 2020 its seventh (and best) year. It had other problems including attempted self-incineration in 2016 (A software bug as I recall). and bankruptcy in 2019. Regulators were threatening to shut it down permanently in 2023. I have been unable to determine if they succeeded.

        Overall, apparently not that incredible a success.

        1. aerogems Silver badge

          Re: Alternative uses

          It shows that the theory is sound, so the rest is just fine tuning the details.

        2. Orv Silver badge

          Re: Alternative uses

          I gather a lot of the bird kills were avoided when they started defocusing the beam when not in use. Apparently initially they were just focusing it above the tower during shutdowns, creating a dangerous "hot spot" in the air.

          1. Michael Wojcik Silver badge

            Re: Alternative uses

            Alternatively, they could partner with KFC and one of those "Punkin' Chuckin'" guys.

        3. Jimmy2Cows Silver badge

          Re: 13sq km of mirrors to heat 3 boilers to 560C

          This really isn't the same thing at all. This is simply reflecting and focussing sunlight onto a salt tank, which heats up and uses that heat to drive a working fluid through turbines, generating electricity. Totally different principle.

          Space solar uses photovoltaics panels to generate electricity from sunlight, converts that electiricy to microwaves of very specific frequency that is not absorbed by water molecules, and transmits that microwave energy to receiving rectennas spread across the ground. Those the microwave energy induces electrical current in those rectennas. Direct electrical conversion. No heating involved.

          Same way that radio waves induces a tiny current in an antenna. Just on a much larger scale, and a very specific frequency.

          Focal spot of the transmitter is deliberately spread out to avoid concentrating a large amount of energy in a small area. The frequency is chosen to not be absorbed by stuff. There's no way anything in the beam will catch fire. This won't kill any birds, down any planes, or anything else.

          Oh, and people keep saying "what if this is hacked and used as a weapon?" It can't be used as a weapon because the beam cannot be focussed tightly enough. That's an aspect of how it is constructed. Not something you can hack in and tamper with. Worst thing hacking could do is move the transmitter (slowly, it's a satellite - it'll have reaction wheels and station keeping thrusters, but that its) or turn it off. It might use a phased array to keep the beam tracked to the receiver, so you could maybe redirect the bam that way, but the beam still can't do any damage.

          1. Orv Silver badge

            Re: 13sq km of mirrors to heat 3 boilers to 560C

            Once you've spread out the power enough to avoid being harmful, haven't you just made your receiving antenna impractically large? At a certain point you might as well just deploy solar panels because they'd be smaller.

    5. Chet Mannly

      Re: Alternative uses

      Exactly my first reaction - what happens when one of these things inevitably gets out of alignment and starts microwaving citizens. Because if you wanna get meaningful amounts of energy out of this it will need to be powerful.

      And not only weaponisation by governments etc - what about hacking?

    6. darkrookie28

      Re: Alternative uses

      You could say the same thing about nuclear power.

      1. Ken Hagan Gold badge

        Re: Alternative uses

        You could, at which point the advantages of putting all of your system in a single, small, ground-based, securable location start to become obvious.

  2. aerogems Silver badge
    Thumb Up

    Archimedes Would Approve

    Think of all the roman ships he could have set ablaze if he had the ability to put a giant mirror into orbit?

    1. Jimmy2Cows Silver badge

      Re: Archimedes Would Approve

      True, if SBSP concepts were based on giant mirrors floating in space. But they're not. Not even close.

  3. Doctor Syntax Silver badge

    A great success. Funding obtained from billionaire. PhDs granted. Papers published.

  4. Eclectic Man Silver badge

    An alternative

    An article in a recent New Scientist concerned using geothermal energy by sinking a borehole near a magma chamber and using the heat to create steam. They 'accidentally' did this in Iceland recently and the steam erupting from the borehole was at about 900C. A great deal cheaper than putting a satellite into orbit.

    "In Iceland, scientists are planning to drill two boreholes to a reservoir of liquid rock. One will give us our first direct measurements of magma – the other could supercharge geothermal power

    ...

    Iceland and many other volcanically active countries, notably Kenya and the US, already tap hot geothermal fluids to drive turbines and generate electricity. But, at the moment, this captures only a fraction of the available energy. A fossil fuel plant uses steam at about 450°C, but standard geothermal fluids are at about 250°C. “It’s quite inefficient at those low temperatures,” says Eichelberger. “So there’s an interest in trying to develop super-hot geothermal.”

    Before it got mired in magma in 2009, the Krafla borehole hit geothermal fluids at around 900°C and a pressure roughly 500 times that of the atmosphere. This generated around 10 times as much power as a standard borehole."

    https://www.newscientist.com/article/mg26134722-100-worlds-first-tunnel-to-a-magma-chamber-could-unleash-unlimited-energy/

    1. Wellyboot Silver badge
      Alert

      Re: An alternative

      It's the 'unleash unlimited energy' bit that concerns me.

      It might just be true..

      1. ldo Silver badge

        Re: It's the 'unleash unlimited energy' bit that concerns me.

        Digging a hole like that reminds me of one of the Professor Challenger† stories from Arthur Conan Doyle. Though the effect was, shall we say, more disconcerting than disastrous ...

        †Yes, he did other things besides Sherlock Holmes.

    2. Chet Mannly

      Re: An alternative

      Yep, but the problem is that the super hot geothermal cools rapidly when used, so it would crust over quickly, which means you then have to drill deeper or constantly find new sources.

      Works in Iceland as it is basically a crust on top of an active volcano, and their low population means they don't need many plants to power everyone.

      1. Yet Another Anonymous coward Silver badge

        Re: An alternative

        So all we have to do to make this commercially viable is to increase the population of Icelanders ?

        1. Ken Hagan Gold badge

          Re: An alternative

          No. You have to reduce the population of everywhere else.

          Harder, I suspect.

      2. vtcodger Silver badge

        Re: An alternative

        Geothermal is a perfectly reasonable source of power. They've been generating electricity at the Geysers complex North of San Francisco for 74 years. A respectable amount -- 900MW currently. There are many other geothermal plants operating in the world.

        There are a few problems.

        1. There's not all that much really hot rock at reasonable depth, so potential easy sites are pretty limited. You are probably not going to site a geothermal plant near New York City or London. Not any time soon. Probably not any time ever. Naples OTOH.

        2. Natural geothermal fields have limits as to how much steam can be generated. Drill more wells than your field will support and your production from existing plants will drop.

        3, Natural sites tend to be near volcanoes. There are certain drawbacks to building infrastructure on volcanoes. Parts of Hawaii's Puna plant including the access road were eaten by a lava flow in 2018.

        4. I personally wonder about what else is coming out of the ground besides steam/superheated water -- Sulfur very likely. Toxic gases? Dissolved salts probably. Probably no problem as long as proper handling and disposal procedures are in place. But still ...

        1. Jellied Eel Silver badge

          Re: An alternative

          4. I personally wonder about what else is coming out of the ground besides steam/superheated water -- Sulfur very likely. Toxic gases? Dissolved salts probably. Probably no problem as long as proper handling and disposal procedures are in place. But still ...

          You are not supposed to think about that. You're especially not supposed to point out that fraccing and geothermal are pretty much the same thing, although geothermal is potentially riskier. So my favourite example is the Eden Project in Cornwall. Hot granite rock, good for geothermal. But also radon, so the water in their loop and heat exchangers slowly become radioactive. Fraccing's arguably less polluting given the hydraulic injection's only done once, or a few times for the lifespan of the well. For geothermal, water recirculates and thus will pick up more pollutants, and the same risks of that contaminating the water table. The water and radiation risk for Eden is low, but high enough to trigger regulatory requirements to be considered radioactive waste.

          Another risk is the inevitable effect of cooling rocks, so they contract and you get earthquakes. One in Switzerland was big enough to cause quite a lot of damage and shut the project down. Or stuff like this can happen-

          https://en.wikipedia.org/wiki/Sidoarjo_mud_flow

          and I think a similar, but smaller thing happened with a geothermal project in Australia. Or in Germany, one was drilled into a gypsum layer, which of course expanded as it was hydrated. It is not without risks, but as accidents happen, at least geologists are getting better at understanding those risks.

  5. elsergiovolador Silver badge

    Con-sole

    [Davos Social Credit Score Management System 1.42.3.543246 Fushitesu/Infosas]

    > info <redacted NI number>

    Jane Doe

    Score: -3435

    Class: Useless eater

    Recent infraction: 17/01/24 #abSejFeD32 Speaking against the ruling party (-10 points)

    > zap <redacted NI number>

    Finding Jane Doe......................................................................................................

    Jane Doe has been successfully zapped.

    Nearest waste management services have been contacted.

  6. herman Silver badge
    Facepalm

    Sol Invictus

    The sun is beaming down from space all the time.

    1. Anonymous Coward
      Anonymous Coward

      Re: Sol Invictus

      Yes, and if we redirect even more of that solar energy to Earth (as per this proposed tech), we'll just be heating up the planet even more.

      1. Ken Hagan Gold badge

        Re: Sol Invictus

        Umm, no we won't, because we'll release less CO2 and so the planet will cool. Global warming is not caused by releasing heat into the environment. It is caused by changing the environment so that it is harder for heat to escape into space.

  7. Anonymous Coward
    Anonymous Coward

    Hell there's some real crackpots in these comments...

    1. Anonymous Coward
      Anonymous Coward

      FTFY

      Did you mean in most El Reg threads?

      Creme de la creme of aging powerless supersized-ego old-farts angry against everything new, and not so new. SARS have mercy.

  8. Anonymous Coward
    Anonymous Coward

    Have we learnt nothing from the dangers of 5G? Do people not realise the problems this will cause? This is very worrying because lets be honest the planet has a high percentage of fucking idiots. If they get it working an viable I'm throwing all my money into tin foil related industries.

  9. EricB123 Silver badge

    Popular Science?

    "The mission was partly funded by billionaire philanthropist Donald Bren, inspired by an article in Popular Science ..."

    Uh oh.

  10. Anonymous Coward
    Anonymous Coward

    Beaming more energy from the sun onto planet Earth, than nature intended. That would cause more global warming.

    1. Flocke Kroes Silver badge

      GEO / LEO

      The old studies are for satellites in geostationary orbit. The benefits are they spend very little time in the Earth's shadow and they remain in place over the receiver. The down side is GEO is a long way away so it is hard to focus power onto a small receiver and at costs much more to get satellites that high.

      The alternative is satellites in Low Earth Orbit. They spend half their life in the Earth's shadow and the other half casting a shadow on Earth. As they are nothing like 100% efficient an converting sunlight into microwaves they would have a net cooling effect.

      Although I have not bothered to check, I assume from the word 'constellation' that this is LEO version with multiple satellites so each ground station gets mostly continuous power.

    2. Ken Hagan Gold badge

      Solar radiation inward is roughly 173000 TW. That's about 10000 times what human activities generate. The reason we don't all cook is that 100% of that input is either reflected or eventually re-radiated at longer wavelengths (such as infra red). It's a giant balancing act and moving the balance point by changing atmospheric composition is far more effective than adding a few thousandths of a percent to the input.

      1. Ken Hagan Gold badge

        Also, the Earth's orbit is elliptical and so the input varies by as much as 20% over a year. This is unrelated to whatever season it might be at a particular point on Earth's surface. The 30% or so that is reflected will vary in proportion. The 70% that is absorbed to be re-radiated later serves to dampen out the annual variation.

        1. DaveLS

          While I generally agree with your points, the variation in insolation due to orbital eccentricity isn't as large as 20%. At perihelion (which currently occurs in northern hemisphere winter), insolation is about 6.9% higher than at aphelion. This can be seen from the ratio of distances and the inverse square law: (152.1Gm / 147.1Gm)² ≈ 1.069

          1. DaveLS

            I should add that the earth's orbital eccentricity varies over a long period (>~100,000 years, as part of one of the Milankovitch cycles), and it's currently at the low end, so there have been —and will again be— times when your 20% is correct (maybe nearer 25%), but many millennia away.

  11. Luiz Abdala

    Ok, Dyson Swarm?

    I read through the article and all that I understood was Dyson Swarm, a precursor to a Dyson Sphere, where you just plant a bajillion solar panels in orbit.

    Neat.

    1. Jimmy2Cows Silver badge

      Re: Ok, Dyson Swarm?

      Dyson swarms are typically around a star, not a planet. They aim to maximise capture of the star's entire energy output. They're a step along the Kardashev scale to a Type 2 civilisation.

      1. Luiz Abdala
        Headmaster

        Re: Ok, Dyson Swarm?

        That's a Swarm that could be in Lagrange orbital point around the Sun and Earth, the Earth itself, the Moon, whatever. We call it Dyson Swarm when it's orbiting the sun directly then. Potato, potato.

        Still a bunch of solar panels floating in space beaming their energy to somewhere in any microwave frequency of choice.

        In fact, it would be a great idea to put them in stationary orbit on the moon, sunny side, if we want a Moon colony with power, while not directly landing there.

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