New Zealand is about to test long-range wireless power transmission
singularityhub.com
singularityhub.com
I am excited and humbled by your support.
At Emrod we have safety and environmental considerations at the core. I’m happy to explain why our tech is not only safe but also has a far smaller environmental footprint than any powerlines, communications antennas, etc.
As with any new transformative technology, there will always be sceptics. All we can do is rely on solid science and engineering, listen to the public and address their concerns.
I invite you to engage us in an open honest conversation. We would love to hear your concerns, thoughts about possible applications, or even just drop us a line to say what you think about wireless power.
Not sure if this is as big a problem in NZ but in Canada beavers and squirrels can and do shutdown sections of the grid - as can falling trees and large frozen branches in the winter. I can see a rural hospital benefitting from a redundant dedicated power source.
This is due to the fact that there is no way to reliably forecast when a bird will fly in front of the link and shut it off. Since the receiver will still need storage or generation, it's probably more economical to just do that in the first place.
A transient object like a bird would not have a significant affect on continuity of supply. it is very small compared to the Tx/Rx surface and doesn't linger in the beam path.
Wouldn't you agree that replacing expensive imported polluting fossil fuel generation with a cleaner and cheaper locally sustainably generated energy is worthwhile?
But the birds moving around...
Guess we shall see. That's what field tests are for.
You cannot guarantee this. The bird could decide to fly directly down the beam path and there's nothing you can do.
Directly from the article:
> The system uses a net of lasers surrounding the beam to detect obstructions, like a bird or person, and it automatically shuts off transmission until the obstruction has moved on.
Since there are so many possible obstructions that could occur, I suspect that the link will continuously turn on and off. This will be worse than before so you'll need local storage or generation to account for these unplanned outages.
This sounds like the kind of thing that is technically possible but in practical probability a once in a millennium event
Wouldn't you agree that replacing fossil fuel based generators with a cleaner and cheaper alternative is worthwhile?
As mentioned in a top-level comment, this could be incredibly dangerous, depending on the properties of the microwave generator. Can you say what the maximum level of power density experienced outside of the laser boundaries will be? Can you give attenuation figures?
The Powerco project is listed as "a few kilowatts." What range of distances do you intend to test?
How do you expect weather to affect efficiency? Have you tested the transmission in a driving rain? Or will you turn off the system in inclement weather?
The distances we are looking at are progressive from a few hundred meters to a few kilometres. Range is only limited by line of site and an antenna size which is practical. Mind you, we can reduce antenna size and increase range by using passive relays.
At the moment we are working with about 60% end to end efficiency. This is not influenced by weather as we are using near-field atmospherically agnostic frequencies.
How is this being handled?
See: http://gsp.humboldt.edu/OLM/Courses/GSP_216_Online/lesson2-1...
And, do you know for certain that it won't interfere with your laser safety system?
Presumably there would be forward scatter and back scatter to deal with I don't see how you could avoid that.
Furthermore, comments about beamforming and that it uses a phased array isn't surprising with regards to the application but you will still have sidelobes, even with a very tight beamwidth / high gain.
And then you have path loss etc, I have no idea how this would actually work - it sounds unfeasible on many fronts.
That's not really fair. High powered microwave transmission is dangerous.
You're claiming near field, non radiating, and so, safe.
Fair enough, but you're also claiming long distance. That requires a little more explanation. They call it "near field" for a reason, right?
There is real people who have real concerns that if they accidentally pass thought the beam of power then they will be cooked.
If the safety of you technology is based on it being installed in such a way that no one would accidentally pass through the beam then you need to explain how that is done.
if the safety is because it is just not dangerous to pass through the beam then you need to explain why that is and if there is a time limit on how long it is safe to stay in the beam.
If you are incapable of addressing safety concerns to a technical crowd like hacker news then I don't see how you would convince the general public to be cool with this.
Just to keep beating a dead horse, stating something is safe because "science and engineering" is pretty much the modern day way of saying because "magic".
Agreed. I have significant experience in this field and I’m having difficulty making heads or tails of half of the company’s explanations here. I can’t tell if it’s an attempt at watered-down explanations assuming a non-technical audience, or if they’re simply trying to change the subject whenever the difficult questions come up.
Now that they’re resorting to ad-hominem (“lazy” comments to legitimate questions without even attempting to answer the questions) I’m becoming even more skeptical.
I guess this goes into the same bucket I have had for new battery/energy storage technologies for the last 10 years: until there is an actual, working prototype fulfilling ALL of the promised features, it doesn't exist for me.
Having been working with IoT hardware for over a decade, I used to get so excited that new advances in energy storage would solve some of the problems. Yeah, I'm still waiting :)
I think this is the case. The founder, or whatever PR employee is handling these comments, has misjudged hackernews and assumed that it is used by the same nontechnical crowd as facebook or twitter.
Pretty sure lots of top researchers use this forum. Talking down to them with a "It works using science and engineering :)" won't go down well.
So it says something that even I can tell that this poor guy is out of his depth. He shows up to HN (a community of smart people who are willing to listen to the unorthodox), solicits questions, and gets defensive when people ... ask him questions.
This won't end well. I'll get some popcorn.
PS: brother, it's "line of sight". I know spelling well doesn't change the world but sheesh.
(Though I don't think you have to be a subject-matter expert to judge human interactions. Just wanted to point out the invalid line of reasoning.)
When someone says "I'm not an expert and even I can see that...", they are presumably implying that even without the technical knowledge required to spot an obvious 'fake' or 'quack', perhaps an impostor, they can still identify said impostor.
In this case that seems to me to be a valid statement. Albeit one of relatively low value, since nothing much has been added to the discussion. All we now know, is, that the impostor has overreached and even laypeople can call their bluff (and an additional audience member has confirmed this to us). But that's it.
I want to see how this is often the preface of someone missing something non-obvious though? What is the non-obvious thing in this case, that the parent commenter is missing?
So even if the conclusion is right, the fact that the person drawing it is uneducated is not a justification for it. After all, the same justification could be given in a case in which that conclusion did not hold.
So, if I am getting this right, we have the following factors: Person A makes a statement (this could be an impostor or not-impostor), Person B observes that there is an impostor at work (or not) and Person B could either be educated or not and lastly, whether they agree or not.
So we have the following possibilities:
1.) A -> non-impostor -> B educated (B trusts A based on shared knowledge, easy)
2.) A -> non-impostor -> B uneducated (B has to trust A, A made argument well enough to convince B, but B has nothing but a 'feeling' to rely on)
3.) A -> impostor -> B educated (B immediately figures out A is a sharlatan based on knowledge, argument ensues...or it's just obvious A is no good)
4.) A -> impostor -> B uneducated (B has figured out A is an impostor, but that could be for who-knows-what reasons and is therefore less valid)
And the conclusion here is that in case 4.), the person has used their lack of education about the subject matter as a way to add weight to their statement (or to embarrass the impostor further), when, in actuality their lack of education just indicates that they have little reason to participate in the discussion in the first place.
Am I now kind of getting it? I feel I'm being slow today, but it bugs me when I don't understand something.
There are two relevant cases:
1. A is a non-impostor, B uneducated -> B has to trust A, but A's argument seems flawed because B doesn't know of the non-obvious feature that fixes the apparent obvious flaw in their argument.
2. A is an impostor, B uneducated -> B has to trust A, but A's argument seems flawed because their is an obvious flaw in their argument that even B can spot.
From the point of view of B, there is no way to distinguish between these two situations, and so their being uneducated doesn't help them spot the impostor.
That sounds major alarm bells to me of either serious technical issues or, perhaps more likely, fraud.
If the tech IS actually working and safe, a proposition which grows increasingly doubtful with every comment you make, you are NOT the right person to be running this thread, and you are doing serious damage to Emrod's PR.
Why do you think 100 mW/cm^2 is 'safe'? You must know from experience this is enough for tissue heating, even from sidelobes many dB down.
Over what ranges do you think this is feasible? With, say 20 km of free space path loss in the 2.4 GHz ISM and 40 dB antenna gain at each end you're going to be at least 50 dB down. Doesn't this mean for things like transmitting power to islands this tech is not useful?
Even if you start at 1 KW in (60 dBm), over 20 km the receiving antenna is going to get about 0-10 dBm, or milliwatts.
With the same generous setup at 1 km and 1 kW you get 10 watts at the far end.
This just doesn't work out.
For micro-power IoT, maybe there's a play, but bulk power delivery this seems a stretch.
In case anyone's wondering, 40dB antenna at either end is reasonably some 14ft across at 2.4GHz, so no small thing.
for instance. Put in a 3 by 5 meter aperture, and bam, 40dB on the nose.
All I'm saying is I hope you have a background in EM. There's lots of stuff that sounds great in approximation and models, but breaks down in reality.
[1] G=4piA/lambda^2 - I tacked on 70% eff which is mid-high for a parabolic dish
There are no sidelobes. We are using near-field and catching close to 100% of the radiated energy.
Range is only limited by line of site and an antenna size which is practical. Mind you, we can reduce antenna size and increase range by using passive relays.
Using a phased array, operating in the near-field. strictly point-to-point between Tx/Rx.
At the moment we are working with about 60% end to end efficiency so sending 1kw means you will get 600w at the far end… not 1w :)
Or are you creating a generic lens that is factory tuneable to the needed characteristics?
Suffice to say that you are on to some of our more interesting IP ;)
At the moment we are working with about 60% end to end efficiency
There's spread over distance. If you've found a way to prevent spread it's either not free space or a change to the electromagnetics fundamentals. It's a really bold claim to make. But maybe I'm misunderstanding something.
I know bullshit when someone spells it out for me.
This company can say all they want about near field tech, but the beam waist diameter relative to wavelength determines the diffraction spread. And that aspect of path loss is proportional to the distance in wavelengths even if there's no "absorption" by the air components. For any reasonable link at 2.4-5.8 GHz the length in wavelengths will be tens of thousands.
Can you link me to reading material explaining how an antenna can have no sidelobes?
Or is there some metamaterial "magic" going on even at the transmitter that I'm not accounting for?
Right, and anybody who knows enough to ask you about sidelobes likely also knows enough to know that too.
That's why, if you reply that "there are no sidelobes" you're only harming your own credibility.
A good reply is something like "there are sidelobes, but they peak at -{believable number} dB and are contained to within {small area}. We believe this is more than sufficient to address sidelobe concerns because of {standards}".
That's a reply that earns trust.
Whereas the question-train you're on is at a pretty interrogative clip ..
Very feasible.
Hypothesis A: they don't want to share basic performance metrics because they contain special secret sauce!
Hypothesis B: they don't want to share basic performance metrics because they suck.
We'll see!
> There are no sidelobes
E.g. The radiating near field of a 2.4GHz antenna about 8 meters long would extend about 1km.
[1] - https://www.giangrandi.org/electronics/anttool/regions.shtml
Unless of course we are beaming directly at a coms antenna, which we don't plan to :)
Thanks for answering questions here!
Here is a chart of transmission losses from the source to the end user across US states: http://insideenergy.org/wp-content/uploads/2015/11/State_Los...
Beyond delivery loss, don't forget that there are other CAPEX/OPEX considerations.
For example, an underwater cable from an offshore wind-farm might be a more efficient means of energy delivery but it's installation and maintenance cost would be much much higher and require more time to deploy than a wireless solution.
That is inevitably a significant part of any economic benchmarking.
70% efficiency is the current state of the art limit for solid state based Tx. we loose close to 0% in the atmosphere and our Rx is well beyond 90% efficient.
What end-to-end efficiency are you getting and at what distance?
For example, we are currently looking at powering an island across a distance of 30km with an end-to-end efficiency of around 60%.
I bet Musk will be your best friend if you brief him with such project ;)
Also curious, what are the advantages over a maser?
I'd imagine they'd never get approved blasting 400w per kW erratically.
We are using a strictly point to point collimated beam that is expected to meet nothing but clear air. It shuts down if/when any transient object is about to enter the beam path.
Also, don't forget that the important figure you should be looking at is power density rather than total power
You also claimed it's unaffected by rain.
Which is it?
Rain will trip the laser screen, as will fog.
Ergo, this will only work in clear air. Rain and fog will shut it down.
This is technology that not everyone is familiar with. Some questions people want to know are surely:
1.) What makes it safe? Is it that the beam itself is harmless? Harmless for long term exposure, too? Or is it that the beam isn't harmless, but the system has systems in place to break the beam if obstructed?
2.) Will other technology be affected? Would drones, etc, interacting with the beam be adversely affected?
3.) HOW is this relatively unaffected by distance? So far I've heard you say that it isn't impacted by the atmosphere, but I think people are still curious to know more.
4.) How is this not impacted by rain/humidity? You linked an article regarding water not absorbing radiation, but didn't address the subsequent claims regarding refraction.
The point is. This is a technical place, please answer some of people's questions and stop just dismissing everyone as ignorant skeptics.
> The system uses a net of lasers surrounding the beam to detect obstructions, like a bird or person, and it automatically shuts off transmission until the obstruction has moved on.
...which seems to be proof that you're aware of it's dangers and have taken steps to mitigate it. This is a good sign in my book.
I also note that the beam is controlled by
> relays, which are like “lenses” extending the beam beyond line-of-sight by refocusing it, are nearly lossless
If you've not reached coherence, how do your control diffusion? Do you have plans to have 'relays' at very regular intervals in order to constrain the beam to an (cross sectional) area so that it remains safe for organic life?
The interval between relays largely depends on topographical, regulatory, and environmental conditions.
In any case, all our systems are designed to be absolutely safe for any organic life form.
Despite initial perception (mostly driven by the 5G frenzy I presume), if you do the research you'll realise that it is the most environmentally friendly solution out there. This is how EBDs can go green! No ELF, no people or animals immersed in RF or electrocuted, no carbon emission, no cutting through forests and rivers with huge pylons and no underwater cables disturbing marine life.
I hope this addressed your concerns?
We don't have high capacity (centralised nor distributed) grid scale batteries in many places yet.
What it boils down it is, even if this works, which I doubt, 20% transmission loss makes this a niche market at best.
NZ is proposing to go fully renewable by 2030 as well as promoting higher EV targets for 2023. We already import many right-hand drive Nissan Leafs reaching their 7-year EOL from Japan, so re-purposed batteries for off-grid storage will become very cost effective in short order.
Our aluminium smelter is also slated to close in a year which frees up about 10% - 15% of national electricity, and we have pumped storage for day/night loads separate from hydro.
Given the political climate here, niche opportunities abound imo.
Is the patent application still unapproved and thus unlisted, or has it been rejected?
The major exceptions are if the inventor files for nonpublication along with withdrawing the application (usually because they think it won't be patentable) or the US Government classifies it.
(I guess this idea can no longer be patented if it is novel, as this comment has just established prior art!)
When an actual expert shows up they often waste effort on the first comments before the good comments have shown up. This was a good effort from an expert and answering questions in no way damages credibility or disproves the efficacy of the technology or any of the other nonsense that has been asserted by a community in decline.
AFAIK, Tesla's theory about how to do wireless power transmission was to use a specially modified absolutely gigantic Tesla coil (a "magnifying transmitter") to resonate the electrostatic sphere of the Earth; spark-gap radio and lightning strikes, only tuned to resonate.
It remains unclear to me if this was ever actually attempted - Tesla's original attempt, Wardenclyffe Tower, was never completed and AFAIK no-one has since attempted it.
None of this has anything to do with this attempt in NZ, since it's a beam, instead.
AFAIK, it's unclear. Spark gap radio (and some interesting observations about lightning strikes) indicate that you can "do stuff" to the Earth's electrostatic sphere, but whether or not that means you can resonate it? And then use that resonance as a way to transmit power? Not clear. (and ofc even if all that works, what're the side-effects?)
AFAIR, most of the "of course it wouldn't work" critiques posit something like a radio broadcast model; instead of the OP's microwave beam, just a microwave broadcaster, essentially, which ofc runs into inverse square law issues. But that's critiquing an entirely different theory of operation, so...
I suspect it's either unworkable in practice (the "resonance chamber" is too complex/dirty to properly resonate) or unfeasible (resonance chamber too damn large), although I wonder if the work done on wave-displays (where you use wave interference patterns to display text) would allow you to deal with those issues. I also wonder if the same ideas writ tiny could be used in MEMs, but that's ridiculously idle and uneducated of an opinion - I know next to nothing about MEMs.
I'd start by looking at spark-gap radio, and progress into Tesla's work from there.
What do you mean about “doing stuff” to the earths electrostatic sphere?
Apparently, lightning strikes do the same thing to the electrostatic sphere. One of the super interesting things here is that, if you measure the speed of 'wave', from, say, Altanta to Sydney, the apparent speed is FTL.... but if you measure the distance as through the Earth instead of across its surface, it works out.
It's also why (apparently) spark gap radio works in caves and tunnels.
I'm relatively sure this isn't faked:
The San Francisco/New Zealand connections make this seem quite likely related...
https://www.atlasobscura.com/places/electrum https://www.lod.org
With only about 300 people, the community on Stewart Island can't justify an undersea cable. But a microwave power beaming system could be built for much less, and supply energy much cheaper (and greener) than burning diesel.
Electricity -> Hydrogen by electrolysis -> Hydrogen at pressure -> Electricity by fuel cell
even if the input electricity is almost free, everything hydrogen seems very expensive.
> However, a key drawback of this “power-to-gas-to-power” route, if electrolysis is used for hydrogen production, is the round-trip efficiency, which is “around 45%,” it says. The report provides an example to illustrate the cost penalty per MWh associated with the power-to-gas-to-power route: “Hydrogen generation from low-cost renewables at $25/MWh with a capacity factor of 50% yields a cost of $1.70/kg of hydrogen produced. Storing this hydrogen underground will add about another $0.30/kg, thus the hydrogen costs $2/kg. If this hydrogen is used to generate power, the resulting cost is $100 to $200/MWh. In ideal conditions (e.g. a CCGT turbine at 60% utilisation), the cost is $100/MWh, while simple-cycle turbines at 25% utilisation would deliver power at $200/MWh.”
> Still, the report is optimistic. Because hydrogen production costs will drive up to 80% of total power generation costs (Figure 3), if the technical feasibility of a 100% hydrogen turbine is proven, the capital expense of hydrogen turbines could “rival that of natural gas turbines by 2030,” it says. For now, however, “companies should use hydrogen-based power for high-value flexible generation first, and two, hydrogen baseload power generation for deep decarbonisation in situations with constrained renewables potential will require strong policy support.”
> The Provincial Growth Fund is putting $3.16 million towards building two wind turbines on Rakiura / Stewart Island
> Mr Parker said building an initial two wind turbines as part of the island's power generation network was the most economic and environmentally acceptable option.
> "It provides a renewable energy source. It is estimated to reduce diesel use on the island by half, which will enable the price of electricity to be stabilised."
https://www.rnz.co.nz/news/political/403869/renewable-energy...
This smelter is also about to shut down in August 2021. So now there's going to be a huge surplus of electricity way down south (the smelter uses ~13% of the country's total electricity!), with the big city way up north.
There are a lot of ideas circulating about what to do with the Tiwai plant, including setting up a Tesla factory (it has a deep water port handy). There just happens to be a source of the purest silicon sand in the world nearby, so one intriguing option is to set up solar panel production, which given the hydro power supply would have very high sustainability credentials.
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Oblivious, because the image was a double negative.
"The photo was a promotional stunt by photographer Dickenson V. Alley; a double exposure. First the machine's huge sparks were photographed in the darkened room, then the photographic plate was exposed again with the machine off and Tesla sitting in the chair. In his Colorado Springs Notes Tesla admitted that the photo is false:
"Of course, the discharge was not playing when the experimenter was photographed, as might be imagined!"
https://commons.wikimedia.org/wiki/File:Nikola_Tesla,_with_h...
Which led to a situation mentioned in one of his biographies, where he was on the far side of the shop and somehow the switch got thrown. It was either make a new exit through a wall or window, or leverage the fact that discharges are sphere shaped but shops are generally box-shaped; army crawl out through the little 'triangle' of space between the floor and the wall/benches outside of the radius. I would hope some new safety protocols were introduced after that, but I couldn't rightly say. The rest of that story sort of overshadows such details in your memory.
Exposing lightning, and an indoor inventor, would require very different apertures and shutter speeds.
As I understand it, sitting nonchalantly while his Tesla coil threw gouts of lightning was a stunt which Tesla would frequently perform.
It took a bit of trickery to produce a photograph of it, sure. But anyone who has been to Burning Man has seen such feats as bands 'obliviously' playing music mere feet from a running Tesla coil.
> To give an idea of the magnitude of the discharge the experimenter is sitting slightly behind the "extra coil". I did not like this idea but some people find such photographs interesting. Of course, the discharge was not playing when the experimenter was photographed, as might be imagined!
https://commons.wikimedia.org/wiki/File:Tesla_colorado_adjus...
If the only issue was one of lighting it, I don't know why he'd express reservations. He says that it was only done to give a sense of scale, not to demonstrate safety ("of course" he wasn't actually sitting there- why "of course" if not for the issue of safety?). If he'd wanted to defend the image on the basis of being basically accurate (ie if he really did have a habit of hanging around next to his apparatus in full force) then it seems like he'd have mentioned it. Why would he "not like" such an image if he didn't think it was a little deceptive?
This book reads it exactly the same way:
> Perhaps the most memorable image was of Tesla calmly reading a book in front of a deluge of sparks; yet this photograph proved little about the inventor’s experiments. Alley had cleverly used a double exposure since it would have been too dangerous for the scientist to actually sit so close to such an electrical storm. Tesla later admitted, “The streamers were first impressed upon the plate in dark or feeble light, then the experimenter placed himself on the chair and an exposure to arc light was made and, finally, to bring out the features and other detail, a small flash powder was set off.”54 The publicity-conscious experimenter claimed he didn’t like such trick photography, but he argued, unconvincingly, that “some people find such photographs interesting.”
https://nvhrbiblio.nl/biblio/boek/Munson%20-%20Tesla%20inven...
This guy hanging around a Tesla coil at point blank range seems to be taking some precautions in the form of a full-body Faraday cage:
So he frequently demonstrated pulling an arc from a Tesla coil using his fingers, with nothing but a brass thimble to protect him from burns.
But the whole point is that it is possible to generate surprising lightning displays with relatively low power (eg high Voltage but low Current).
I would think that in the 5-10 years it'll take to get this safe enough for a commercial product, solar + battery would be scaling and they'd never be able to catch up on price due to the efficiency ceiling.
Maybe there's something possible in aviation for this. There might be electric drones/planes applications which would be way better if they didn't have to carry batteries.
They struggle to get powerlines/phone lines through already so I'm not surprised they're thinking this might be a valid option to relay power for small settlements.
You must live in a large, flat, country.
Take a look at a topographical map of New Zealand.
The tyranny of the rocket equation makes launches super expensive because rockets have to carry fuel to lift the fuel and so on.
So it we can provide energy for a launch from the ground it could be amazing.
However, electric planes could benefit a lot from not having to carry their battery.
But if you did have such an engine/transmitter maybe you could make an electric plane that gets recharged as it passes over transmitting stations on the ground.
If you get a lot of power, the simplest concept Would be an electric heater to increase the temperature of the propellant above what it could get through combustion. The higher the temperature the greater the expansion and the more thrust per pound of propellant is obtained.
I don't want to do the napkin math but my gut is the most practical electrical mechanism to get enough delta-V to LEO is a railgun but doing the acceleration up front would have probably have undesirable effects on the payload.
[0] https://en.wikipedia.org/wiki/Variable_Specific_Impulse_Magn...
Imagine a spacecraft with a mass of 100 tons (including fuel and payload). Let's also assume a specific impulse of 2,956 (the highest thrust version of VASIMR according to this source: http://www.projectrho.com/public_html/rocket/enginelist.php#...). If we require an acceleration of 2 g and assume that our engine is 100% efficient we would require about 28 GW of electricity. This is approximately equivalent to the average electricity consumption of California. I don't think it would be possible (with current or projected future technology) to build a receiver that could handle 28 GW of electricity and still stay under 100 tons. If we could build such a receiver I don't think it would be able to survive accelerating through Earth's atmosphere.
The silver lining, though, is that wireless power transfer is a very useful technology for use in space after getting to orbit. Lasers are probably a better technology than microwaves for transferring power over interplanetary distances, but the concept is the same. If we ever travel to another star there is a pretty good chance that the journey will be at least partially powered by an array of very large lasers.
I've always been curious as to how effective a hydraulic lift could be at reducing necessary launch weight. A disproportionate amount of fuel is used at the beginning of the first stage when it is the heaviest, so seems like the benefit would be quadratic - Saturn V took 12 seconds to clear the tower. Would require major infrastructure, but if you could "throw" the rocket so it starts at a greater initial speed, seems like you could bend the rocket equation favorably. Perhaps even a giant underground potato-canon or railgun.
I suppose you'd be able to approximate the effect by comparing the delta v needed to launch from a sea-level site (Cape Canaveral, Kourou, etc.) with that needed to launch from one of China's inland sites (e.g., Taiyuan, which sits at 1500m). I have no idea whether this data is publically available, though. I'd guess the bulk of your performance improvements would come from increased engine performance due to the lower ambient pressure (~0.83 atm according to Wolfram Alpha) rather than the increased altitude, since most of the energy is needed for horizontal acceleration [0]. The increased thrust would mean lower gravity losses, but I wouldn't be able to say how much.
https://www.nasa.gov/topics/technology/features/horizontalla...
So far all demonstrations have been of rockets mounted under a jet engine powered aircraft, which then detaches at space launch. But I don't think there is any reason why you couldn't have a SSTO air/spacecraft, other than we don't have the propulsion technology yet - it works in KSP though :-)
But that’s the whole point, with traditional rockets every second spent on the way up is wasted fuel combatting the cumulative force of gravity.
But if your energy is being beamed up, as long as that energy is enough to overcome gravity, you eventually achieve orbit. You’re no longer burning a limited resource just to “hover + 1”.
I’m not saying it works, but it does fundamentally change the equation if you can beam “fuel” to the rocket on the way up.
Unfortunately energy =/= fuel. In the end, mass has to exit the rocket at high velocity out one end in order to provide acceleration in the opposite direction, and that mass is limited.
would also like to know if/how it will affect mobile phone towers
Are you gonna screw with my WiFi way over here in Sydney?
;-)
At 2.4GHz, λ is approximately 0.125m. Since the wavelength is small, the antenna is likely to be "electromagnetically long", i.e. the size of the antenna is of comparable size to the wavelength.
The edge of the near field in this case is defined by the Fraunhofer Distance [0][1]. Let's assume we want the edge of the near field to be 1km away. Running that through the Fraunhofer distance equation to compute the largest dimension of the radiator, we get ~7.9m. That's huge. For 10km it is 25m.
0. https://en.wikipedia.org/wiki/Near_and_far_field#Electromagn...
> ...system uses a net of lasers surrounding the beam to detect obstructions, like a bird or person, and it automatically shuts off transmission until the obstruction has moved on...
I guess i assumed any obstruction would suffice in triggering the lasers...but now re-reading it, maybe the obstruction has to be more significant.
More: https://teslauniverse.com/nikola-tesla/articles/tesla-invent...
https://en.wikipedia.org/wiki/David_Edward_Hughes
Nether Marconi or Tesla could claim to have "Invented" Radio as the principles were well documented before they started work.
- we are using nearfield. No sidelobe.
- 2.4 - 5.5 GHz
- long distance (I am assuming km’s)
Is there anything to read so I can better understand the technology?
For example, 10 foot antenna, 4Ghz == 12 meters of "reactive near field" or ~250 meters of "radiating near field" though the claim is it's not radiating, therefore it's safe.
Either this is bs, or something important isn't being said.
The sensor + electronics part is what is different today from what Nikola Tesla could do.
But the ISM band usage might suck for anyone who needs high SNR for other use, because the scattering on moisture + a 1kw/sqm power delivery means it will look like shining a laser through a dusty room.
Is this in my head? Am I safe to use this radio at full gain? Should I not keep it by my desk?
Microwave ovens operate at 2,450 MHz.
https://www.seeedstudio.com/RF-Explorer-model-WSUB1G-p-922.h...
... along with a high dB external attenuator because it is designed for low power. According to the docs a 60dB external allows for 1 milliWatt to 2 Watt measureable input. I think the default power for 2.4ghz Wifi is 100mW.
That said, they are looking at tissue heat as the main threat. This IEEE study shows tissue degeneration in lab tests associated with WiFi exposure, with most effects showing in later measurements across a 6 month period.
https://www.researchgate.net/profile/Azuwa_Ali/publication/2...
This paper also demonstrates very significant effects on liver enzymes, consistent with the other study. It was interesting to see both studies observed increasing effects over longer periods of exposure. https://journals.sbmu.ac.ir/aab/article/view/19283
Most of the info on EMR on the web is disastrously bad. Somatosensory amplification is common among people with certain behavioral health diagnoses, and the web has certainly amplified that- but a lot of this dates back to the days of tin-foil hats. I’ve tried to focus on finding decent quality info and found a lot of noise and fear-mongering opportunists around this subject.
My little survey this evening leaves me still a bit concerned. I find no reason to think those papers aren’t credible, but I would welcome any criticism you can point me to.
Intuitively it seems to me that if EM energy is powerful enough to move large amounts energy and information, it’s powerful enough to erode systems in its path, even without ions or heat.
While I understand case 1 and I worry some people don't understand that even if we get the tech figured out it's going to only make sense in certain contexts (at least until/unless we have infinite `free` power), but I think #2 is a bit weird.
Yes building that infrastructure to the wind farm is costly/difficult but also... It seems weird to bottleneck the generation at the gen site. I guess if the infrastructure costs for wireless transmission are minimal you could get things bootstrapped easier/cheaper but it def seems shortsighted if you're already creating a big loss at the first stage of generation.
The system consists of four components: A scientifically illiterate public, a gullible trade press, desperate capitalists, and wide eyed entrepreneurs riding the hype cycle all the way to the exit.
> microwave energy—an electromagnetic wave just like Marconi’s radio waves, only a bit more energetic
Sorry for the nitpick, but, the difference between microwave and longer wavelength radio waves is frequency, not energy! I see this all the time in popular science reporting and it drives me nuts... Microwaves are electromagnetic waves, just like UHF, VHF, etc., except that they are a higher frequency (and thus, shorter wavelength). In fact, in general, longer wavelength radio waves are often transmitted at higher power than shorter.
Unless they mean that this microwave energy transfer scheme itself is using more energetic radio waves than other types of radio systems... but it doesn't read that way to me.
If you feed 1 watt of power into a 10Mhz isotropic antenna you get a photons of a certain energy spreading out in all directions. If you feed 1 watt of 10Ghz into a isotropic antenna, are you saying that the photons have more energy than the 10Mhz version? Where does the extra energy come from?
I'll admit it's been way to long since physics class, so forgive me.
Power != Energy
You see it reported all over as energy because that is the correct term for what is being discussed.
Disclaimer: I'm involved with them.
Except instead of a LED converting electricity into visible EM radiation, it's an antenna that converts electricity into a focused beam of microwave EM radiation. And on the other side instead of a solar panel you have an antenna to convert back from EM into electricity.
A similar example is WiFi/Bluetooth where you have antennas converting electricity to EM radition and back. Except they're at much lower power - well under a watt for phones/laptops, and up to a watt for routers, and generally the antennas are omnidirectional instead of focused.
If you really wanted to use visible light instead of microwave and not have antennas you could do a laser and a solar panel to get effectively the same product. Pretty sure laser power transmission is a thing with some niche use cases.
This setup proposes to use 100mw/cm^2. That's just not acceptable unless you're sure no humans or animals are going to cross the beam (or even it's sidebands!). Even a horn has diffraction sidebands, and unless they're all at least 8dB down in all situations that's bad. The laser trips won't cover this.
This exceeds the safety standards established by the US Navy back when they were dealing with their high powered radars for the first time. They found that anything over 10mW/cm^2 can cause enough heating in animal eyes to cause clouding of the eye. Humans' deep set eyes and brow ridges help (depending on freq) but 10mW/cm^2 can still cause health issues. The measured e-field for that powerlevel, depending on wavelength, will almost certainly be above the electrical field limit for exposure in the USA. I hope that's also true in NZ.
I wasn’t able to find a report of that happening at the Hofn station, but the same story of this happening to an anonymous microwave technician does appear in other locales.
Snopes did a debunking on these and they say it’s false: https://www.snopes.com/fact-check/nuke-of-earl/
Note: They are ~900Mhz, so short of "microwave", but pretty close.
If you got locked in there.. then sure... maybe.... but staying in there and not feeling it (or just feeling "warmer", until you die...) nope.
(Technically, an Earth-based space elevator would still most likely be beaming from inside Earth atmosphere, but at least it would be pointed approximately straight up and probably be positioned in the ocean or other sparsely-populated area.)
This place is pretty depressing sometimes.
A lot.
Do you harsh on people who remind you how dangerous it is to work on live electrical outlets or wear long sleeves in a chemistry lab?
Some of the “negative” HN comments gave me exactly the information I was interested in that the article hadn’t mentioned.
NZ has a strong system of regulations and licensing around transmitting.
Maximum exposure to non-ionising radiation is set out in NZS 2772.1, which is based on the guidelines from the International Commission on Non-Ionizing Radiation Protection.
All transmitters require approval from Radio Spectrum Management, and any system like this being deployed would require a resource consent from a territorial authority under the Resource Management Act, at which point the Department of Conservation would submit on any adverse effects on local wildlife.
This is such a typical internet armchair thing to do. Point out some Google-able “flaw” and wonder aloud whether the team of scientists and engineers have considered it.
(with or without Near Field considerations)
Why do you think that Radio Astronomy dishes are so humongous?
Surely you do not expect Emrod to discuss in detail the subject matter of its patent applications?
But some guy on the internet says it won’t work.
I believe this was an ad buy bought by marketing at PowerCo rather than some "R&D" department (hint: they don't have those at NZ power companies). It likely didn't get more than a layman's eye.
Have a meeting with a few stakeholders there next week, will ask about it. Also reaching out to Callaghan Institute who funded this.
Another way to say it is 1 kilowatt per square meter. It's a lot of energy. A 1500 watt electric heater can get my entire bedroom quite a bit hotter than with just the central heat running. Put 2/3rds of that energy into your body and there are certainly going to be effects.
This is an urban myth.
http://www.schoolphysics.co.uk/age16-19/Wave%20properties/Wa...
That may or may not be true, but you're bringing up a point they already addressed.
“Even a horn has diffraction sidebands, and unless they're all at least 8dB down in all situations that's bad. The laser trips won't cover this.”
I don’t really understand this. My guess is that they’re saying that besides the targeted microwave band, other high/low frequencies will be emitted (sidebands) and that these will diffract and be way outside of the directional beam that’s protected by the laser trip wire.
I would assume the inventors have at least some explanation for this, but a fluffy article won’t go into those details.
Live wire accidents happen because people operating equipment capable of hitting the wires are looking elsewhere because looking elsewhere is a fundamental part of doing their job. The crane operator looking at the load or the helicopter pilot watching something on the ground is who hits a live wires. Not hitting live wires is caused by knowing where they are ahead of time and planning your work so you don't hit them. Making the wire invisible doesn't really change that. It's not like this tech would be used for residential lines where every Joe schmoe is operating a man-lift.
Unfortunately, this is typical armchair, internet commentary some people prefer instead of doing actual research.
I have crunched the numbers again on a new envelope, and with some realistic Tx/Rx panel size (3 meters) at 5 GHz, I see how you may end up with 70% efficiency assuming diffraction limited panels but also with 100% efficiency of the electronics.
Since I have the idea that you are part of Emrod, I would like to ask you why you opted for rectennas at receive and not some other antenna tech? Is it simply the integration between antenna and rectifier (smaller footprint?) or are there more reasons?
3 meter diameter panels @ 5 GHz gives a diffraction-limited beamwidth (FWHM) of lambda/D = (3e8/5e9)/3 * 180/pi = 1.5 degrees
0.75 degrees (1.5 degrees is the full angle) gives tan(0.75×pi/180)×(2×40) = 1 meter panels at receive (40 meter from transmit) to intercept the FWHM power. So a 3 meter receive panel will intercept more than the FWHM --> 70% seems like a realistic number for the percentage of power intercepted.
A Rectenna is just a dipole with a rectifier at the feed point.
They could be in a phased array (of dipoles), or in the center of a parabolic reflector.
There is no possible way to increase on efficiency in a passive antenna.
So could any other type of antenna, basically. It doesn't have to be a dipole, though.
> or in the center of a parabolic reflector
Based on the images, that's not what happens here
> There is no possible way to increase on efficiency in a passive antenna.
That is absolute horseshit. Large dipole arrays will suffer from high mutual coupling which could drastically reduce performance (depending on design choices). Different antenna types might be more suitable for different scenarios, but that's why I would like EmRod to explain their choices.
Furthermore, a rectenna gives you DC power out, but why would EmRod want this?
The ITU has allocated 12 different ISM bands world wide, with some local differences.
see the "Table of Radio Spectrum Usage in New Zealand"
https://www.rsm.govt.nz/assets/Uploads/documents/pibs/ff001f...