[HN Gopher] Flying kites deliver container-sized power generation
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Flying kites deliver container-sized power generation
Author : geox
Score : 140 points
Date : 2024-01-18 15:56 UTC (7 hours ago)
(HTM) web link (spectrum.ieee.org)
(TXT) w3m dump (spectrum.ieee.org)
| JoeAltmaier wrote:
| Gotta be more to it. They blithly say, reeling it in takes a
| fraction of the energy it generates when it pulls the line out.
| But that's nonsense on the face of it.
|
| I'm guessing, it changes it's wind profile, maybe going edge-on
| or closing up, to make it easy to pull down again. Gotta be
| something.
| greesil wrote:
| I think the kite might have control surfaces, thus would be
| able to control lift by changing its angle of attack.
| cjbgkagh wrote:
| Trailing edge control lines, pretty standard. You let them
| out and the kite will no longer be able to catch the wind and
| will float down. Keeping some tension on those lines and
| wenching it in will keep the kite controllable.
| datadrivenangel wrote:
| Brake lines on a traction kite like that can cause the foil to
| fully de-depower and fall out of the sky. So you can let the
| wind pull it up, and then let gravity bring it down.
| jdiff wrote:
| Only as much nonsense as rowing a boat without taking the
| paddle out of the water. In that specific example, you're going
| to be going in circles, but you will be moving.
| pacaro wrote:
| You can propel a boat forwards with only one oar, without
| lifting it from the water. It's a useful skill, Kayakers use
| the same stroke to move sideways, and for stability in rough
| water. See https://en.wikipedia.org/wiki/Stern_sculling
| jdiff wrote:
| Exactly, that's why calling this concept nonsense is so
| weird. It might be a tiny bit counterintuitive at first
| glance, but there's plenty of examples of it all around.
| LazyMans wrote:
| On its face it sounds silly, until you get experience with wind
| surfing. It's using the same concept. Figure 8s generate the
| pulling force. When you stop the figure 8s, and change the
| angle of the kite, you get minimal pulling force.
| pierrekin wrote:
| > Reeling it in takes a fraction of the energy it generates
| when it pulls the line out. But that's nonsense on the face of
| it.
|
| Why is this nonsense on the face of it? This is just how kites
| work. Do you imagine that kite surfers just overpower the kite
| with their might and pull it back to the ground when they've
| had enough?
| JumpCrisscross wrote:
| It's also how turbines work. The fluid pushing on one side
| isn't cancelled out by the drag created on the other.
| jollyllama wrote:
| >The energy generated by the system while reeling out is
| greater than the energy consumed to reel the kite back in.
|
| There's something about it that just triggers the "perpetual
| motion machine" identification heuristic.
| zardo wrote:
| On a multi line kite you can control the angle of attack and
| speed. That gives you the ability to dial the pulling force
| up and down over a large range.
| bentpins wrote:
| You're not wrong - they do that.
|
| Have a look at https://thekitepower.com/products/ There's a
| diagram of the flight path and power generation over the
| cycles.
|
| The flight path on the way out is much much longer going cross
| wind in figure 8s. On the pull back in it's a direct path back
| in, and it looks the kite shifts to point back at the base
| station more so there's a ton less resistance than on the way
| out.
| jitl wrote:
| I'm happy to see this idea continues to develop. I was worried
| its failure was foregone when Google shuttered their moonshot
| Makani in 2020. It seems like this iteration is simpler.
| SCM-Enthusiast wrote:
| for some reason, this always happens with the google moonshots;
| They come at it from the wrong angle. Someone comes along with
| a slightly simplier solution after google scrapes the whole
| thing as uneconomical or beats them to the punch on using a far
| more technical solution. Don't seem to have a big "Cost per
| KWH" KPI's internally nor a sense of urgency.
| pfdietz wrote:
| I wonder how Malta is doing. The News blurbs at their website
| seem... ok?
| skyleradams wrote:
| Not to be a HN naysayer, but wasn't this tried already with
| Makani Power?[1] They even made a documentary about it[2]
|
| Compared to traditional wind turbines, this solution trades an
| enormous amount of complexity, maintenance, etc for small
| reductions in material cost. We should be churning out
| traditional wind turbines for cheap instead.
|
| [1]https://x.company/projects/makani/
|
| [2]https://www.youtube.com/watch?v=qd_hEja6bzE
| jdiff wrote:
| The article poses a different use case, replacing diesel
| generators for off-grid power, not hooking into the grid to
| replace turbines.
| cjbgkagh wrote:
| This is a very different approach. The google approach is
| making an airplane fly in circles generating continuous power,
| this slowly lets a kite out then reels it in generating pulsed
| power that would need a battery to smooth out. This approach
| can use pretty standard kite technology which is far cheaper
| than airplane technology.
| jacquesm wrote:
| Use multiple kites in a staggered pattern so one of them is
| always generating near peak power. That complexity of course
| offsets all of the gains, but that's fine because it
| illustrates why this is an idea that just won't fly.
| cjbgkagh wrote:
| Batteries are fine, the majority of the time it'll be in
| the pull stage as once depowered (the power is taken out of
| the kite by releasing the brake lines) you can bring the
| kite back down pretty quickly. Having two with the cycles
| staggered would reduce this but you need batteries anyway
| because you can't rely on demand being flat.
|
| The algorithms to control the kite are pretty
| straightforward, the complexity to self launch would be a
| bit tough but it's easy enough for a human to do so there
| is no need to include that complexity for the use cases
| this is targeting. This wouldn't be a set and forget
| solution, not yet.
|
| The kites will wear out relatively quickly but they're
| cheap to replace.
|
| I consider myself a pretty skeptical / practical Engineer
| and I don't see any show stoppers, I think it'll fit the
| niche they're targeting quite nicely.
| jacquesm wrote:
| From both a maintenance, operational cost and engineering
| complexity point of view I don't see this as viable, but
| I'm more than happy to be proven wrong by a party that
| brings it successfully to market. Meanwhile, any place
| where this kite system would work is one where a regular
| HAT would work as well and long term (25 year lifespan)
| total cost of ownership and $/KWh generated will be
| pretty easy to determine by deploying two systems side-
| by-side.
| Vvector wrote:
| The article indicates that it comes with an integrated
| battery.
| bobbob1921 wrote:
| which also includes a small amount of solar apparently
| rtkwe wrote:
| It'll make sense in some places where it's harder to
| build/deploy a 40kW traditional turbine. They're not easy to
| move and are relatively close to the ground so they are viable
| in fewer places than kite systems because winds aloft are much
| higher than those near the ground. You can also use this
| temporarily in areas where you have periodic power requirements
| and poor access to the wider electric grid. Think about
| deploying a lot of these in areas right after hurricanes or
| other disasters.
| ksenzee wrote:
| Not to be flip, but the fact that Google canceled a project
| doesn't say a whole lot about whether that project was viable.
| jacquesm wrote:
| The fact that Google funds a project isn't evidence that it
| is viable either.
| patall wrote:
| > Not to be a HN naysayer, but wasn't this tried already with
| Makani Power?[1] They even made a documentary about it[2]
|
| So? These (kitepower and skysails, but there are more) are long
| standing 'competitors' of Makani, all existing for far longer
| than 2020 when Makani went down. Just because Google gave up,
| not everyone else also gave up. I mean, Google also stopped
| Google code, groups and google+, yet similar products are still
| triving.
| datadrivenangel wrote:
| 60 square meters of kite surface area is a lot of pull. 5 square
| meters can be enough to pick up 100kg in the right wind
| conditions.
| helpfulContrib wrote:
| A sailboat typically flies about 5 - 8 square meters of
| material in the sails, pulling 3 - 4 tons of material around
| the world ..
| pierrekin wrote:
| This doesn't seem right to me, in my experience a 3 - 4 ton
| sailboat is around 9m long, which has a sail in the 20 - 40
| m^2 range.
|
| A 5 - 8 square meter sail is really teenie tiny.
| zardo wrote:
| Yeah, that's sailboard territory, or a small dingy with no
| intention of going fast.
| usrusr wrote:
| Robotic boat, a large tank, some power-to-storable tech, a
| power generating turbine beneath the waterline and a huge
| kite. Just send it out on the oceans, to cruise aimlessly
| wherever the satellite uplink suggests favorable weather and
| have it head home when the algorithms assumes that remaining
| tank capacity might get filled up on the way back. Most
| attractive post-fossil future ever.
|
| Unfortunately, unattended power-to-anything is very much a
| far away dream, despite all delusions of being able to do it
| large scale on Mars. All other technology is basically ready
| to go, and the "lateral lift" of a fast-moving boat is a
| perfectly adequate substitute for mooring when it comes to
| tapping wind on the high seas.
| IshKebab wrote:
| Based on the numbers from the article: 40 kW * 80 s / 500 m is
| 650 kgf.
|
| So maybe it will work. Still I feel like as soon as you get a
| moment of calm it will all break. The wind may be very reliable
| in places but is it ever so reliable that you don't get moments
| of calm for hours at a time?
| pierrekin wrote:
| When there is a break in the wind, you reel the kite in,
| creating apparent wind.
| datadrivenangel wrote:
| The diagram envisions the kite also being connected to a
| battery, diesel generator, and solar PV installation.
|
| The real question is not if the kite installation or
| renewable installation is 100% reliable, it's a question of
| how much does it cut your total diesel consumption. US
| military loves renewables because it reduces the amount of
| fuel they have to move.
| TSiege wrote:
| Yeah I see this as making a lot of sense for armies as a
| first customer. Highly mobile, reliable energy supply you
| can set up anywhere (assuming their claims are correct)
| onthecanposting wrote:
| I never saw that in the Army, but maybe I was in the wrong
| kind of unit. I wouldn't count on good continuity between
| statements of the upper officer corps (political
| appointees) and the operational realities of the line of
| business personnel. Just like any big organization.
| boringg wrote:
| Operating the kite isnt easy on its own. A lot of complexity
| involved in this. I am intrigued as someone who kites and
| develops clean energy. I have a tough time seeing how this is a
| set and forget situation. Maybes it the first step in a direction
| with something better down the road!
| Gys wrote:
| > After the tether reaches its maximum length, the ground
| station winches the kite back in. Though the Hawk must expend
| energy for reel-in, it only expends a fraction of the energy,
| resulting in a net energy gain that varies by wind speed. An
| entire cycle takes about 100 seconds: 80 for reel-out and 20
| for reel-in.
|
| This is an interesting approach. Also, the kite is doing eights
| all the time. Although I suspect that is only while reeling
| out.
| tonyedgecombe wrote:
| Presumably they can adjust the attitude to make it easier to
| real in.
| brlewis wrote:
| My recollection from flying kites a long time ago is that
| operating a kite gets easy after a certain height. I imagine
| the Kite Control Unit (KCU) can easily keep it aloft once it's
| high enough. The tether is 352m long according to
| https://thekitepower.com/the-hawk/#components
| nothercastle wrote:
| I don't think you can make a kite that can last a decade of load.
| We just don't have materials strong enough. Also you need a
| sophisticated algorithm to fly it and never crash
| dtx1 wrote:
| As someone who regularly flies hobby kites, I think it can be
| done.
|
| Modern kites are made of nylon and kevlar. With regular
| maintenance these kites should last at least a decade. Cables
| might have to be replaced every few years.
|
| As for the flying algorithm, I doubt it has to be very
| sophisticated at all, especially if the kite is itself designed
| to self right and stabilise. After all, a single line kite has
| 0 controls.
| nothercastle wrote:
| I sort of assumed it would power and depower like a
| kiteboarding kite to create work. You could probably depower
| by collapsing the kite leading edge and dragging it back in
| but that seems less efficient than flying it in a figure 8 to
| power and depower.
| smusamashah wrote:
| How is the kite raised initially and what happens when air stops,
| how is it re-raised?
|
| Reading the article seems like it's pulled back if air is
| stopping, and slowly released based on air speed perhaps.
| cjbgkagh wrote:
| On islands where this is targeted the winds are usually very
| predictable, especially at higher altitudes. This isn't like
| flying a kite at ground level, there is no need to wench the
| kite back down to ground level, just up and down where the
| faster high altitude winds are.
| timdiggerm wrote:
| All of the raising is done by the wind.
| tamimio wrote:
| I wonder how they will deal with bird attacks. Falcons and
| eagles (ironically, they share the same name with this kite)
| are territorial and will go after these drones. I once had a
| huge heavy-lift drone that got attacked too. But with a pilot
| nearby, the easy solution is to fly to a higher altitude, that
| seems to determine who rules the sky in their eyes apparently.
| I'm not sure how this kite will manage such situation.
| patall wrote:
| By being 60m2 big? I mean, helicopters are also not being
| attacked by eagles, why would this kite be?
| tamimio wrote:
| Helicopters do get attacked, not so common because of
| several factors like the size, flight behavior, altitude,
| and most importantly the engine size and placement, these
| birds from my observation they usually attack from behind
| and/or above, both are properly "protected" in the
| helicopters, not so much in this kite, additionally, when
| the pilot is flying, they usually avoid it and continue
| their path, the birds mostly won't chase and lose interest,
| but this kite is stationary and if the bird decided that it
| is hostile, it will keep trying to prey on it especially
| when you can't increase the altitude substantially like a
| normal drone.
| adrianmonk wrote:
| Wind power machine idea #1: turbines.
|
| Potential concern with idea #1: the machines may kill birds.
|
| Wind power machine idea #2: kites.
|
| Potential concern with idea #2: birds may kill the machines.
| Vvector wrote:
| People cannot be anywhere in the radius of the kite cable. Kinda
| limits where is can be deployed. But the quick deployment could
| work for some situations.
| brlewis wrote:
| Details: https://thekitepower.com/the-hawk/#space_requirements
| shkkmo wrote:
| This is not correct. Untrained people can't be inside the
| flight zone while operating. This is roughly the downwind
| quarter of the potential flight zone.
| Vvector wrote:
| Even a quarter is a huge area. Using the "safety buffer"
| radius of 425m, that is 560k m2 or 140 acres. A quarter of
| that is 35 acres, for 30 kW.
|
| For regular wind turbines, it's 30-70 acres per MW generated.
| That is 20x-40x more power for the same land area. And almost
| all the land under a wind turbine is freely usable.
| krisoft wrote:
| > Untrained people can't be inside the flight zone
|
| What kind of training makes you immune to being sliced in
| half by a tether?
| shkkmo wrote:
| The same kind that makes you immune to crashing a car,
| none. However the training presumably could help you asses
| and mitigate risks better than someone with no training.
| MostlyStable wrote:
| Are these less visible than traditional wind mills? If so,
| maybe they could be used at sea and get around the hatred of
| wind power as an eye sore.
| tamimio wrote:
| You can probably deploy it inside the solar farm, most of the
| times these aren't open for public to wander around.
| antisthenes wrote:
| So it's just a really big battery.
|
| The kite thing is just a novelty/marketing move. There have been
| containerized commercial battery systems available for at least a
| decade. The barrier to adoption is, as always, price, not "kite
| delivery".
|
| Is this for really remote places, like Greenland/Alaska? Because
| otherwise you can just use a truck/tractor.
| 123pie123 wrote:
| I'm surprised other ideas have not taken off yet?(intended)
|
| although not really a kite, this looks promising :
| https://www.youtube.com/shorts/zGGn-HY1jak
| brazzy wrote:
| You completely misunderstood. The kite is not for "delivery",
| it actually generates the power.
| qnsoaejacniln wrote:
| How will this work with aviation? I know it probably won't affect
| most IFR flights, but still possibly dangerous for VFR. Will
| there need to be a new restricted area for each deployment?
| nameless912 wrote:
| Depending on the altitude, they could keep these within class G
| airspace, which means VFR's job is to see and avoid. I think
| that's a pretty defensible solution as a pilot who spends all
| of his time in VFR operating in Class E/G airspace.
| tamimio wrote:
| A project I did a couple years ago was to have an onboard SDR
| that communicates automatically with airplanes in the vicinity,
| or switching to manual where the drone operator can communicate
| as if they are "on-board" through the internet by a mic on
| ground. I can see something like this is doable, with a
| modified system to fit the length flight, after all, the
| position is fixed so I don't think it would be a problem.
| qnsoaejacniln wrote:
| Just wondering, how were you communicating to the airplanes
| in vicinity?
|
| Radio would require the planes to be listening on a specific
| frequency and ADSB Out would require the planes to have ADSB
| In which is not guaranteed.
| tamimio wrote:
| It wasn't an ADS-B, Transport Canada (the FAA equivalent in
| Canada) doesn't like ADS-B on drones yet, so the solution
| was to have an SDR (BladeRF, full-duplex for Tx/Rx), the
| on-board SBC had a server the received the voice sample
| (either direct through ground station MIC or automated
| reading directions, alt, etc every X period of time) and
| then broadcasting it to the airband, so it's simply:
|
| Ground station mic -> internet -> server on SBC -> SDR ->
| airband (AM, I think it was ~120Mhz that time) -> other
| pilots
|
| If you have the manual communication (where the drone pilot
| comms and not an automated broadcast), you can pretty much
| talk with pilots as if you are on-board.
|
| I had a better write up if interested on how it works in
| here, in the "SDR" section.
|
| https://tamim.io/professional_projects/nerds-heavy-lift-
| dron...
| qnsoaejacniln wrote:
| Super cool!
| Nick87633 wrote:
| At first look, it seems like simply by having so much less mass
| of material involved that you have a good head start at competing
| on LCOE, even if the system needs the kite and tether replaced
| every 5-10 years.
|
| I think the biggest roadblock would be making sure it can return
| to the perch with high reliability otherwise you will have a lot
| of service calls for kites that landed on the ground.
| nirolo wrote:
| There's been a recent video by the German "Sendung mit der Maus"
| (basically how does stuff work for little children) about these
| kind of generators. I did not double check if the company in the
| video is the German one mentioned in the article, but chances are
| high. Video and subs are in German only, but it's less than 10
| minutes and one can see a little how it works.
|
| https://m.youtube.com/watch?v=aqfFZDWiJOI
| NullPrefix wrote:
| Why are these people wearing safety helmets? Does this imply
| that everyone living under the kites will have to wear one too?
| IanCal wrote:
| They're under a crane lifting stuff up overhead on a work
| site, that's probably why.
| NullPrefix wrote:
| but it's not a construction site though
| throwuwu wrote:
| Falling bolts and tools don't really care if they're on a
| construction site or not
| sambazi wrote:
| no, it's because the are directly at the site where the kite
| is launched (and on national tv)
| dtgriscom wrote:
| Very cool. I noticed that the radio-controlled unit that steers
| the kite has its own little wind turbine for power.
| tamimio wrote:
| I wish if there's an actual video of the whole system being
| operated and not just 3D renders, a lot of questions in mind
| about some details but probably most of them will be answered in
| such video.
| jimmySixDOF wrote:
| I can only imagine how many 3D models they render in a physics
| simulation platform like Nvidia Omniverse so they likely just
| used what they already had.
| mikepurvis wrote:
| I've always loved this idea since hearing the Swift Navigation
| founders talk about it in their Kickstarter video:
| https://www.kickstarter.com/projects/swiftnav/piksi-the-rtk-...
|
| Glad to hear there are people still working on it.
| sytse wrote:
| This is the best article on the problems of airborne wind energy.
| It is 10 years old but I think Michael Barnard did a great job
| explaining all the variants and why it is hard
| https://czmphorfqgktmzxu.quora.com/Airborne-wind-energy-a-co...
| michaelbuckbee wrote:
| You were not kidding. That article really covered a lot of the
| obvious questions I had (and was the single best thing I've
| ever read on Quora).
| Scea91 wrote:
| Interestingly, the very first statement is quite misleading. The
| statement:
|
| > On average, a humble wind turbine uses less land area per
| megawatt-hour than almost any other power source.
|
| The article itself refers to this citation [1]. It says,
| unsurprisingly, that the most land efficient power source is
| nuclear. The statement is of course technically true because it
| says "almost any power source".
|
| With wind, however, even that is tricky because you can either
| count just the area directly below the turbine body, which is
| still higher than nuclear and unreasonably optimistic because you
| severely limit a far bigger area. If you count also the spacing
| (too pessimistic on the other hand because part of the land might
| be used for farming) then wind farms range across the whole scale
| of land efficiency.
|
| I think its fair to say that land use of wind farms is
| "complicated", but saying its almost the best in this regard
| sounds like manipulation.
|
| [1] https://ourworldindata.org/land-use-per-energy-source
| londons_explore wrote:
| Wind turbines can be built big enough that the blades, at the
| lowest point, are higher than almost all other land uses,
| except perhaps forestry.
|
| To be honest, the access roads are probably the biggest real
| impediment to using the land around a wind turbine. Can't
| exactly farm millions of acres of corn with robotic combine
| harvesters with a criss-cross of access roads to the base of
| every turbine.
| kingkawn wrote:
| Why not? Seems easy to teach the robots to not harvest on the
| road
| londons_explore wrote:
| Odd shapes and constantly starting/stopping the
| plougher/seeder/harvester mean you get less ROI on your
| equipment. Farming is super tight margins - if your
| machines waste 20% of the time starting and stopping every
| time they pass over a road, your farms profits are wiped
| out.
|
| This is true whether the machines are robot driven or not,
| and it's the reason most commercial farms have _huuuuuge_
| fields rather than lots of small ones.
| mulmen wrote:
| Why would the access roads create a complex shape? Fields
| already have access roads. Either the farm is flat and
| the turbine access roads can be on a minimally invasive
| grid or the turbines are on a hill and the fields are
| already a complex shape.
| nwiswell wrote:
| > if your machines waste 20% of the time starting and
| stopping every time they pass over a road
|
| This seems absurd. How do the grain carts get the crops
| to market without roads? There are roads in any farm. The
| combines simply make a U turn to stay in the same field
| rather than crossing the road, and move on to the next
| plot when one is complete.
|
| Really this is just an argument against having a
| ridiculous density of wind turbines, which as I
| understand would be deleterious to the efficiency of the
| turbines anyway.
| jeffbee wrote:
| And yet. https://www.google.com/maps/@43.0700265,-95.6508704,
| 3a,60y,9...
| dtgriscom wrote:
| Beautiful image: thanks.
| tomatotomato37 wrote:
| That's a turbine in the middle of active farmfield, off a
| dirt road, servicing a town a bit under a mile away that is
| barely 10 city blocks wide at its widest point. In the
| middle of Iowa.
|
| My point just because you can build the turbines to clear
| everything, there are areas in this nation where there's
| just no point to doing that; and it's more economical to
| just make them shorter and put the money towards something
| more useful
| m4rtink wrote:
| I'm not sure robotic combine harvesters are a real concern
| (yet ?) - modern "manned" harvesters are already crazy
| effective and fast & I've seen them navigate some pretty
| crazy field geometries at times, so I'm sure they can handle
| a straight road.
| zensavona wrote:
| Sounds like the article used just the right wording then.
|
| "...less land area per megawatt-hour than almost any other
| power source." As I read it this implies there is one (or some
| very small percentage) power source which uses less land per
| megawatt-hour, which is exactly the case.
| saulrh wrote:
| An offshore wind farm by definition uses no land area :V
| OtherShrezzing wrote:
| I'm wondering if the OWID data takes the 3,400km^2 of exclusion
| zone from Fukushima and Chernobyl (more like 5,000km^2, see
| below) into account when calculating the average size of a
| nuclear plant?
|
| I think if we're saying the space beneath the blades can count
| towards aggregate wind-power land use, an argument can be made
| to include nuclear wasteland in the aggregate nuclear-power
| land use.
| soperj wrote:
| Chernobyl's exclusion zone is 4143km^2, and Fukushima's is
| 807km^2.
| s0rce wrote:
| Shouldn't you include in the average nuclear sites that
| didn't explode?
| mulmen wrote:
| Why? Nuclear plants can and do melt down.
| aerzen wrote:
| There are nuclear plants that have been decommissioned
| and have not exploded. So using just this data, there is
| a probability that a given nuclear plant will melt down
| in its lifecycle. And that probability is greater than 0,
| but far less than 1.
| mulmen wrote:
| Yes but wind turbines can't melt down in that way. Even
| in a worst case scenario the literal blast radius is
| smaller. This has to factor in to the possible locations.
| xyzzy_plugh wrote:
| Of course it doesn't. We don't build nuclear generators with
| pre-approved unusable exclusions zones. This is a ridiculous
| suggestion.
|
| Should we consider the potential blast radius of the
| catastrophic failure of wind turbines as well?
|
| You literally cannot build structures in the path of a wind
| turbine if you want it to function.
| OtherShrezzing wrote:
| >Of course it doesn't. We don't build nuclear generators
| with pre-approved unusable exclusions zones. This is a
| ridiculous suggestion.
|
| I'm not suggesting we assign 5,000km^2 to each individual
| nuclear plant, just in case they explode. I'm suggesting
| the 5,000km^2 that currently exists as barren nuclear
| wasteland should be included in the total land attributed
| to nuclear energy. That would bring down the average
| generated energy per km^2 pretty significantly.
|
| The dataset does what I've suggested for hydroelectric. The
| dams are relatively tiny (and in fact, would outperform
| both wind and nuclear in this dataset), but they render
| huge areas unusable. The unusable collateral land is
| attributed to hydroelectric power, as it should be.
|
| It stands to reason that collateral damage caused by
| nuclear should be included, if collateral damage by
| hydroelectric is too.
| beebeepka wrote:
| > I'm suggesting the 5,000km^2 that currently exists as
| barren nuclear wasteland
|
| Aren't you exaggerating by quite a bit?
| worik wrote:
| > It says, unsurprisingly, that the most land efficient power
| source is nuclear
|
| Not true if you factor in waste storage and the time to store
| it
|
| Long after all the nuclear energy has been used making your
| toast, and long after many cycles of climate change, you will
| still be storing hi level nuclear waste, and monitoring it.
|
| But who cares about tomorrow? Party on, and let future
| generations pay!
| frankthepickle wrote:
| looking at the article, you're really splitting hairs - wind
| and nuclear are 0.3 and 0.4km2, many of the others are 20+
|
| if you were to ask someone based on that if wind was one of the
| techs that use least land, it's an obvious yes.
|
| I think you're being more disingenuous than the article..
| dukeofdoom wrote:
| why not a blimp?
|
| Come to think of it, I'm kind of curious why a RC blimps have
| never become popular. I own DJI drones. But no blimps.
| Abekkus wrote:
| Helium supply is an issue and blimps are risky in adverse
| weather. Also these kite models keep the generator on the
| ground, saves from trying to float so much delicate weight.
| jrockway wrote:
| Interesting! I always try to guess how these things work before I
| read the article. My imaginary design would have the kite pull a
| heavy weight up and as the weight moves, it rotates a generator.
| When the weight reaches the end of the travel, it falls back down
| and the cycle repeats. The flaw with this design is if the wind
| was strong enough to pull the weight up, then the weight is not
| going to be able to fall back under its own power. That's why the
| real design just uses a motor to do that. Makes sense!
| 6gvONxR4sf7o wrote:
| I used to work on this at a different company, and I'm glad to
| see work on it continuing! It's one of those things where the
| physics works out really great for fantastic power generation,
| but the engineering is just so damned complex, so it's tough
| to... get off the ground.
| londons_explore wrote:
| I think the Google approach suffered from _too much
| engineering_. Specifically they had sunk too much money and too
| many people at very expensive prototypes before they 'd gotten
| the design even close to running reliably. As soon as you
| become a big team, you become _less nimble_ - which isn 't what
| you need when your product still has big unknowns.
|
| They should have started with five 2 guy teams, a year and a
| budget of $50k each, and tried 50 different ways to get a scale
| model that could reliably not crash in all weather conditions
| for a few months on end.
|
| Only when you have a craft that can either survive all weather,
| or reliably pack itself away whenever the weather changes
| quickly, then figure out how to scale it up and make it
| generate power.
| thechao wrote:
| The back-of-the-envelope analysis for kite-based power is
| very compelling; enough that I tried my hand at designing a
| kite-powered system in ~2004. I don't think anyone can really
| appreciate how challenging the engineering (control systems)
| are for all-weather kite-flying until they just try to reel-
| in & reel-out a kite on a relatively calm day. I literally
| couldn't even _write-down_ the differential equation which
| describes the inverse control path for the kite, when there
| 's one vector for the kite, and one vector for the tether,
| under the reel-in load; none-the-less, solve the equation,
| and then get it to work with a freakin' stepper motor.
| londons_explore wrote:
| Don't take the hard maths approach when you can take the
| lazy AI approach... Just fly a kite by hand, log the data,
| stick it through a reinforcement learning system to make
| you a controller that keeps the kite in the air.
|
| Reinforcement learning loves these kind of problems that
| only have double digit numbers of scalar inputs and
| outputs.
|
| Either way, my kite flying experience tells me that your
| reel-motors must move with quite some speed and power if
| you are to keep the kite in the air when the wind suddenly
| reverses direction.
| trefn wrote:
| I wonder if you could make the kite itself lighter than air to
| avoid issues where the wind dies down? E.g. a kite shaped
| airship.
| usrusr wrote:
| There are no issues, at least as long as you can supply power
| to the base station: just make the motor/generator reel in the
| kite, that causes plenty of movement relative to the stationary
| air to keep it afloat and controllable right down to the
| reefing mechanism.
| dandrew5 wrote:
| Is there anything stopping them from adding a turbine system to
| the kite that would continuously spin (when there's wind ofc)
| instead of reeling it in/out?
| soperj wrote:
| Why would they ratchet the kite in instead of making it dive and
| quickly winding the cable in? Should be easy enough with software
| right?
| purpleidea wrote:
| How long does the Kite and Dyneema rope last before either breaks
| and one or both need replacing? Their site
| https://thekitepower.com/the-hawk/#space_requirements mentions
| the lifetime for the battery and ground station, but I'd be most
| curious about the durability of the whole system.
| dendrite9 wrote:
| I suspect looking to sailing would get you the best answers as
| an outsider. Dyneema ropes are used for sailing but I don't
| know about the replacement rates, or if they are replaced
| preemptively for racing where the risk of an issue after some
| use is too expensive and replacement is cheaper. I have have
| seen lots of parachute or hot air balloon fabric offered
| because companies have a limited number of hours of use before
| they retire them.
| russellbeattie wrote:
| After seeing Big Hero 6, I've always wondered about the
| feasibility of giant floating blimps with generators...
| Aeroi wrote:
| As a longtime kiter and sailor, the durability of the kite and
| line system seems to be the biggest weakness. Constant uv
| exposure and stress to these systems would make the economical
| calculations interesting. I don't know of a current setup that
| could see sustained continuous use for 1 year without significant
| material replacements or maintenance...
| UncleOxidant wrote:
| I worked at a small kite power startup in 2019. Unfortunately we
| couldn't secure funding to keep operating. It became quite
| difficult to secure funding after Google suspended their Makani
| moonshot project - potential funders were like "well, Google got
| out of this so why do you think we should fund you?". (though our
| kites were much smaller than Makani's and we didn't need a huge
| amount of funding to keep developing)
|
| It's a very difficult problem keeping a kite flying in a figure 8
| pattern allowing it to rise to the end of the tether and then
| effectively stalling it to pull the line back in - repeat over
| and over and while you're at it try to maximize power output for
| the weather conditions (and then there was the problem of
| automatically launching - we were leaving that for last). We were
| starting to look at reinforcement learning for the problem, but
| it was going to take a lot more data and a very accurate model of
| our kite and weather conditions.
|
| Definitely one of the more fun jobs I've ever had even if it was
| short-lived.
| behnamoh wrote:
| > potential funders were like "well, Google got out of this so
| why do you think we should fund you?".
|
| Google shuts down projects and products because it's Google and
| can't productionize ideas. It's sad that this results in such
| secondary effects.
| tschwimmer wrote:
| I know nothing about kites but as someone who currently works
| at Google and knows a bit about how projects are funded, the
| first argument doesn't really make a lot of sense to me. At
| Google's scale, a materially impactful opportunity needs to
| have the opportunity to generate billions in revenue and have
| high margins. That's just a function of Google's size and
| opportunity cost (people can otherwise work on Ads, Cloud,
| etc). However, just because something isn't a Google business
| for Google doesn't mean there isn't an opportunity for a (very)
| profitable or successful business. Sounds pretty weak - perhaps
| the VCs you guys were pitching to were more focused on SaaS vs
| hard tech.
| UncleOxidant wrote:
| I think they saw Google's decision to defund Makani as a sign
| that kite power wasn't viable. We certainly weren't in the
| same league as Makani - their "kite" was essentially a
| largish 4prop airplane. Google must've spent in the several
| hundreds of millions on that project. Our prototype kites had
| a ~8' wingspan and we were operating on a shoestring budget.
| scblock wrote:
| Article needs an editor: "As of late 2022, the world contained
| about 900 megawatts of wind power capacity." I've worked on
| single projects larger than that. Presumably they mean gigawatts?
| dtgriscom wrote:
| 900GW it is:
| https://en.wikipedia.org/wiki/Wind_power_by_country
| samstave wrote:
| Have you folks ever heard of a company called CAT?
|
| They tend to make things for pushing around dirt.
|
| So, TEU containers are TINY. What if - we used an army of CAT-
| like dirt movers in key areas to FUNNEL wind through a bunch of
| "wind-tunnel" type things and feed higher power wind in the
| directions we prefer?
|
| Maybe call it "planetary vehicular land transmogrifcation" - or
| "terra-forming" for short?
| xg15 wrote:
| It's an amazing project, but, out of curiosity: Why do all the
| AWE projects except Google's seem to use the reel-in/reel-out
| approach and don't attach turbines to the kite itself? Reel-
| in/reel-out seems a lot more complicated, power inefficient and
| taxing on the material than just having the kite up there (semi-)
| permanently.
|
| I assume there are some technical reasons why turbines are less
| practical, but could anyone explain what those are?
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