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.
What frequency are you using and over what bandwidth? How many dB down are your sidelobes from your main beam? Are you using parabolic reflectors for your primary antennas, how big are they relative to your wavelength (what's the beamwidth)? What role do meta-materials play, are they the collimating relay? What about the sidelobes on the relay?
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.
The antenna size is governed by the wavelength and the distance between Tx and Rx (or relays).
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 :)
As far as I understand it near-field effects stop being relevant at a couple of wavelengths away from the transmitter. For 2.4ghz that would give you what, a meter of distance?
Can you link me to reading material explaining how an antenna can have no sidelobes?
Near-field is only a few wavelengths away when the antenna itself is a half wavelength in dimension. Otherwise you would calculate the size of the near field as a function of the physical dimension of the antenna and the wavelength: r2 = 2d^2/λ.
E.g. The radiating near field of a 2.4GHz antenna about 8 meters long would extend about 1km.
Right, but even a phased array will give you sidelobes, it's only a question about reducing them, right? Your claim that there are no sidelobes at all seems a bit dubious to me.
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}".
"I'm not disclosing basic performance metrics because you might reverse engineer my secret sauce from the basic performance metrics"? Really? Seems unlikely.
Yeah, there aren't enough details here to prove the claims. Not to mention, how much power do the "transmitting relays" use. Those sound like they need to be active devices that require a power source. Yes you can siphon off power from the beam, but with all the losses involved it doesn't seem to make sense.
Does this mean that the meta-material lenses are custom built for each relay station? For example, to bend the beam around fixed obstacles like a mountain. Do you believe this will be a barrier to manufacturing and installation?
Or are you creating a generic lens that is factory tuneable to the needed characteristics?
If path loss doesn't matter to you then you've revolutionized both communications and war.
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.
Eliminating path loss has always been relatively easy if both ends never move. I’m assuming they mean negligible spread over the distance tested instead of no spread.
I work with radio, and I'm not sure how exactly you are "eliminating" path loss on any sort of real world link, even ones fixed in position. Even very high gain antennas and very small wavelengths are going to spread the energy out to some degree over any non-trivial distance (most links I work on are 10km+, so maybe your definition of non-trivial distances are different than mine).
Maybe they found a frequency that is not absorbed by the athmosphere that much. Seems far-fetched with the gas mix that the athmosphere is, but I guess that such frequencies would be company IP.
Instruments that sweep all frequencies have been available since shortly after the dawn of radio and public atmospheric absorption tables have been available for nearly as long. Also, absorption bands tend to be very broad in this region, so after 10 or 20 data points there's nowhere for a magic frequency to hide.
You are correct. There's no magic at work here. We don't break the laws of physics, we just flex them with clever engineering... like most innovators that came before us.
Path loss through free space at these relatively low frequencies (<6 GHz) isn't from air/water vapor losses. It's from diffraction spread.
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.
The equations governing diffraction are relatively straight forward. We are operating within the near-field (or more accurately in the Frensel range). I'm sure you can do the math and see how focusing a phased array can reduce diffraction at this range :)
This reference from 2007 wherr a lab at MIT demonstrated wireless power transfer, may be relevant for explaining inductive coupling and the idea that this is not radiative (far field) power transfer - correct me if this technology is fundamentally different:
Coupling has nothing to do with Emrod tech. Its intrinsically limited to low power and small range. It is also has a much more significant impact on health and safty.
Ok understood. The "near field" comment made me think it was the same thing... I don't understand how this works then (not a criticism, just a walking back from thinking I got it)
Indeed [1]. For context I design antennas for a living (yes including "meta-materials", AESA, and high power), so not the first wireless power transfer design I've encountered. If this is different, awesome, I'd love to read a whitepaper.
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
You posted personal attacks repeatedly in this thread. If you do that again we will ban you. We've had to warn you more than once about breaking the site guidelines already.
If someone else is making false claims, show how the claims are false, so we can all learn something. Don't just tell that they're false and especially not in noxious ways like this. Not only do you poison the community when you post like this, you also discredit any truth that you're trying to defend: https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor...
Other commenters have expressed skeptical reactions while staying within the guidelines. Please be like them in the future.
By the way, the claims in the OP probably are too good to be true, because most claims are too good to be true. But if we're to have an interesting forum in the long run, people need to correct bad information by respectfully providing good information, not by bashing each other in uninformative ways. Perhaps you don't owe someone who is making false claims better (I'm speaking only of the general case here, not the OP)—but you definitely owe this community better if you're posting to it. Please do better from now on.
My first knee-jerk reaction was rather negative. But I came across this:
> 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.
Given NZ's geography, a niche like providing remote pilot projects power until cable or renewables are constructed would make the tech worth pursuing. You could back out without sunken costs or environment damage if the pilot doesn't go ahead.
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.
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?
This is NOT "incredibly dangerous". This is the sort of lazy internet commenting that doesn’t rely on actual research.
There will always going to be sceptics. All we can do is rely on solid science and engineering and engage people to address genuine concerns.
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.
Dismissing legitimate concerns by calling them "lazy" and "sceptics" is unhelpful.
Stating your technology is safe due to "science and engineering" without explaining the science/engineering is unhelpful.
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".
> Dismissing legitimate concerns by calling them "lazy" and "sceptics" is unhelpful
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.
having gone through the employees of the company and looked at their backgrounds and how long they've worked at the company, and the CEO (guy in thread) describes himself as "Serial tech entrepreneur and growth hacker, with over 15 years trajectory in deep tech, Internet, and mobile. Turning great ideas into successful businesses. Specializes in Disruptive Innovation, Rapid Prototyping and Technology Commercialization.", basically, this Emrod guy will have no idea how this really works. Their "lead" scientist is a guy called Ray Simpkin, who seems reputable, but hasn't really worked in this area too much, and so far their only demonstration is something over 2m. I got a feeling reality is going to bite this company in the ass, but happy to wait for actual evidence of long range transmission. It seems everything is pretty much hype based on a lab experiment, likely trying to get some investment $s
Thanks for digging that up, helps in setting the expectations for the whole thing to correct level.
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 :)
Thanks for your 5 minutes of research, biased interpretation, insulting use of quotations and incorrect summary of "this Emrod guy will have no idea how this really works". I know some of the people on the team and can assure you that they know how it works.
There's nothing wrong with creating an account to post a comment about a situation you have some personal connection to. On the contrary, we want people to post about what they know—and if they wait for a topic they know something about, so much the better for the rest of us.
>an attempt at watered-down explanations assuming a non-technical audience
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.
I'm about as unqualified to comment on this general topic as your average 6th grade dropout. To me, a "sidelobe" sounds like something you'd get at a shopping mall ear piercing stand.
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.
It's interesting how 'I'm not an expert and even I can see that...' sounds like a convincing argument, but it is often the preface of someone missing something non-obvious.
(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.)
I'm probably about to embarrass myself, but I got stuck on this comment. I am trying to make sense of it and I can't. Can you please help me out:
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?
Haha, I don't see how your comment should be embarrassing. So often when something seems "obviously wrong" for , the reason for that is not because it is actually wrong, but because it only appears so for non-obvious reasons that elide those without subject-matter expertise.
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.
Thank you for the elaboration. And thank you for sticking with me here :)
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.
The cases in which B is educated doesn't really matter for the point I'm trying to make.
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.
I haven't found any of the comments in this thread particularly alarming. However, I find your overall defensiveness, inability to answer simple technical questions directly, and your tactic of answering questions with questions casting doubt on the asker to be extremely disconcerting.
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.
Between Tesla FSD, Neuralink, Nikola, the litany of fake listed Chinese companies like Luckin, this is truly the golden age of fraud. No surprise if this is one.
It's also the age of NZ launching it's own satellites. Sadly this thread bumping up against the Nikola investigation seems to have tainted this thread with doubters. Growing up in NZ we are taught to have an inventive spirit even without resources. Using "number eight wire" as we call it. Stories about farmers inventing jet-boats to head up rapids looking for lost sheep, or a young Peter Beck with a rocket on the back of his bike, then naming his rockets after Rutherford. Not saying every kiwi invention is a winner, but don't let the knockers put you off trying is all.
How do you handle rain scatter? I'm not an RF engineer but my understanding is that rain scatters GHz range signals quite effectively. It doesn't absorb them, but it would unfocus the beam.
I hope you have a better source for your claim than that! That page only says that water won't absorb the radiation. Even if water is transparent in those bands, you still have to deal with its refractive index, which can mean reflection and scattering. Have you tested this?
And, do you know for certain that it won't interfere with your laser safety system?
I'm far from an expert in this field but rain scatter is definitely a thing on all GHz bands. It's more of a problem (or a way of propagation depending on how you see it) with 5GHz and up. Climate and the size of the droplets also matter as the wavelength changes.
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.
Why use lasers? Why not just monitor input power and output power, and if the difference is too great infer that the power is being lost somewhere (ie. being absorbed by an obstruction) and back the power off until the losses/obstruction go away? Either have a dedicated radio /other data link to send this information between the rx/tx, or the information could be modulated onto a power beam if there happens to be one running in that direction. Such a system would be inherently safe compared to defining a beam width with lasers, as it is directly monitoring the thing that causes damage (absorbed power).
(I guess this idea can no longer be patented if it is novel, as this comment has just established prior art!)
Cool tech. Out of curiosity have you considered using this technology as a backup source for hospitals and other critical infrastructure? Maybe via dedicated access tunnels underground in a city or a rooftop antenna in a more rural area?
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.
Wouldn't a generator serve this role more easily? Less physical infrastructure, and what happens if the remote (only a few km) transmitter is also blacked out?
Not exactly a fair comparison, and dodging the point. Use a hydrogen generator if you prefer. Or a battery for that matter (as indeed our cars are headed). Point is it might be easier to be self-reliant (calculated local storage) than contrive a secondary power delivery pathway.
How do you reconcile the fact that this would still require local storage or generation resources at the receiving end? If to make this safe there are lasers to detect beam intrusions and shut off the link, users who require a steady supply could never depend on your technology.
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.
Hi, not sure how you came to the conclusion that "still require local storage or generation resources at the receiving end". the whole point is replacing those with a steady connection to the national grid. the only difference being it would be wireless rather than copper based.
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?
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.
Else where in thread someone said 100 mw/cm^2. Not great, not terrible. Maybe 1/5 of putting bird in a microwave. Cooking time would be long but you may be able to get it to work
Can you clarify the 70% efficiency claim in the article? I assume this is 70% efficiency of DC conversion of received power, and not any sort of end-to-end metric?
Reporters sometimes tend to pretend they are novelist and get many details wrong (to put it mildly)
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.
Wow! Please do set up an aggressive schedule to build the first space solar station. The Earth urgently needs its Dyson swarm already. With such distances under test you are very close to the goal.
I bet Musk will be your best friend if you brief him with such project ;)
Your Linkedin profile mentions a US patent for "SYSTEM AND METHOD FOR LONG-RANGE WIRELESS POWER TRANSFER", yet the only Google result is that Linkedin profile or yours.
Is the patent application still unapproved and thus unlisted, or has it been rejected?
Almost all patent applications are published after 18 months, even if they are still unapproved, or indeed will never be approved.
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.
Its in the article. ISM band. typically 2.4-5.8GHz. there are a number of safety measures. some based on a feedback loop, laser safety screen and others. cant go over all those details in a gimmicky article :))
You're posting in a tech community that specifically wants the details that go deeper than a "gimmicky article." Based off of your comments here, you're acting like a rude charlatan.
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.
Will this disrupt other signals in the ISM band? If E2E efficiency is 60% there's maybe 30% radiating uncaptured? 400w is enough to jam anything else using the band for a long ways, maybe a kilometer?
No "erratic blasting" intended :) this is NOT like a strong WiFi.
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
End to end efficiency is absolutely critical for making any wireless power endeavour viable.
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.
HackerNews commenters can always be counted on to do two things: assume that they are more informed than anyone else and refuse to read the article.
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.
There's lots to read! Unfortunately, separating the woo from the real...
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.
It's been awhile... You sever seen a slow-mo of a water balloon being hit by something? There's a wave that kinda travels through it.
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.
It's been awhile, and my understanding wasn't great the first time, but.... no? Spark gap radio works in caves, but not in space. EM waves == photons, right? That's Marconi radio.
70% efficiency is nothing to sneeze at. Stewart Island, which they envision serving with a commercial system, is powered by diesel generators with a cost of electricity of ~$1/kW-h. It's about 50km across the water from Bluff, where there is a surplus of energy due to a large aluminum smelter served by a dedicated hydroelectric plant.
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.
Island sited renewables (wind and solar) are probably a better option than high power radar through free air. Two wind turbines are enough to displace half of the diesel fired generation. Just need more turbines, solar, and some batteries.
> 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."
A number of studies have been done over the years exploring wind, solar and other alternatives. Unfortunately, they aren't perfect. non, including the two turbine solution, comes even close to providing the energy required and will still require diesel generation and LPG on the island. there is no more room for anything beyond 2 turbines on the island so it a partial solution with no scalability. Emrod can provide x5 the current energy required on the island, cheaper, replacing Diesel and LPG, future proofing supply continuity, with a far smaller environmental footprint.
> where there is a surplus of energy due to a large aluminum smelter served by a dedicated hydroelectric plant.
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.
This is great to hear, that extra power (if the South<->North New Zealand HVDC Interconnect has the capacity [1]) will help push out New Zealand's last coal plant on the north island and possibly some of the gas generation [2].
We'd have to build a lot (billions) of new distribution infrastructure to get the Manapouri power to Auckland.
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.
> 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.”
Yes, it's essentially the same architecture: two large phased arrays pointing at each other. The terrestrial technology development could transfer to the space application, or vice versa.
I think i've figured out how they are doing it. This is copy paste about a company he co-founded on his linkedin page. Case cracked! Psychic power transfer... awesome.
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"A famous image of inventor Nikola Tesla shows him casually sitting on a chair, legs crossed, taking notes—oblivious to the profusion of artificial lightning rending the air meters away."
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!"
Tesla's biographers Carl Willis and Mark Seifer confirm this."
Tesla had figured out the math for the minimum safe distance from his coils and had a habit of building the biggest one he could get away with in the shop space he had. Which meant they tended to nearly exactly fit into his workshop.
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.
Tesla doesn't seem to have entirely endorsed the procedure:
> 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!
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.”
I wonder how they're thinking about this versus the steady march of solar + battery performance.
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.
Yeah that's the idea. But if you have somewhere remote enough that's there's no power there then solar and wind are competitors to building wires. There are thousands upon thousands of houses in the US that choose to put up solar and wind and use batteries vs spend $50k to have wires pulled. Same for wells and septic vs city water and sewer.
Probably thinking about west coast of the South Island, New Zealand. Its rugged weather down there, still no mobile reception for most of it, sparsely populated and right up against the Alps.
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.
Solar + batteries competes with wires by being distributed. You install as much generation as you need, right where you need it. In this context you could think of it as a "wireless power receiver" and the sun as the transmitter.
Yep, and fair enough, NZ is a lot more bumpy. It's still not that difficult to install rooftop solar etc. in most situations, even if it's not applicable to every case, though.
I don't think wireless electric spacecraft are really viable for getting into Earth orbit, at least not in the foreseeable future. In order to escape Earth's gravity well, a spacecraft must be accelerating at more than 9.8 m/s (1 g), and realistically at double or triple that rate to minimize fuel consumption.
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.
> ...and realistically at double or triple that rate to minimize fuel consumption.
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.
Power density of direct heat exchange engines exceeds anything chemical rockets have to offer us at this stage. Beaming about 80MW would help get rid of the first stage of a rocket which represents about 80% of carried weight. I imagine this would cut space payloads cost significantly :)
Even without the weight of the first stage, I'd imagine this would have to be a massive quantity of balloons. Lifting an adult human takes a house-sized amount of balloons. Fun to imagine dragging a stadium sized quantity of hydrogen balloons a mile up before detonating them with the engines, but likely impractical. Perhaps rockets could be launched from the top of a giant zeppelin once it reaches altitude? (~4 orders of magnitude larger than the Hindenberg)?
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've always been curious as to how effective a hydraulic lift could be at reducing necessary launch weight.
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.
A space plane is going to be more efficient. The idea is you fly the aircraft with jet engines (which use oxygen in the air) to their maximum altitude, and then switch over to rocket engines (which use oxygen in the fuel).
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 :-)
I think the only way to do that (in principle) would be to make an electric jet engine and power it wirelessly, which becomes less efficient and powerful the further from the transmitting array and thinner the atmosphere before replacing the atmosphere with its own propellant (you can't push against nothing in a vacuum).
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.
I guess it really depends on how much power they can transmit.
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.
That's essentially how a jet engine works but replacing the combustion chambers with electric heaters - and it sounds really expensive in terms of power consumption. An alternative is a kind of plasma propulsion engine called a VASIMR [0] engine.
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.
I'm certainly not an expert of electricity nor radio nor microwave emitters, and such...And, the approach here sounds really amazing...But would a heavy enough downpour of rain act as a strong enough obstruction to trigger the lasers? In essence would weather - at least precipitation - have a negative impact here?
Using 2.4GHz-5.5GHz means minimal (if any) weather related interference. Rain wont have any effect...unless its heavy enough to bring down the antennas. but thats going to be an issue for any outdoors structure such as pylons or communication towers.
If you are using 2.4 GHz, how are you remaining in the near field yet extending the distances out to many km?
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.
> ...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.
good question. also, would it be affected by other elemental forces such as strong wind, snow (rural NZ!), earthquakes, temperature, the gamut of the sun's output, etc.
would also like to know if/how it will affect mobile phone towers
If this is functional I think it would have huge implication w/r to disaster relief. Much easier to start transmitting power to an area wirelessly then start repairing broken infrastructure.
All the fussing over Marconi was a bit painful to read through - it's not "Marconi's radio waves" - Tesla was there first too. Unfortunately it happened after both their deaths but Marconi's patents were invalidated and Teslas were held up. It's annoying to see this myth about Marconi still perpetuated.
Thanks, I was thinking the same thing. Marconi deserves credit for developing the concept of radio as we know it for long range communication whereas Tesla invented radio and demonstrated remote control but did not pursue communication.
https://en.wikipedia.org/wiki/Invention_of_radio#Tesla's_boa...
Radio waves were discovered by Hertz long before Tesla or Marconi were working in the field. When it comes to actual applications of radio, Marconi was certainly much more influential than Tesla despite him holding some early patents. It is also with noting that nationalism probably influenced the american court's ruling against the british Marconi Company [1].
No, you're right. They call it near field for a reason. Likely single or double-digit meters in distance depending on the antenna size for that frequency range.
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 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.
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.
The introduction is a bit off. Tesla even invented the concept of radio before Marconi but only utilized it for remote control. Marconi invented the concept of radio for long range communication.
https://en.wikipedia.org/wiki/Invention_of_radio#Tesla's_boa...
The introduction is really off. The image of Tesla and his transmitter was a double negative, no wonder he looks so relaxed. He wasn't actually sitting there with the transmitter turned on.
I’m totally uninformed about wireless power and it’s safety, but it seems like a lot of people in these threads are so I’d like to fire it this question: can high gain 5Ghz WiFi cause any adverse health effects? I just got a new MikroTik router yesterday that has a really high gain radio on it. It shipped with the 5Ghz dedicated radio disabled, and I have it sitting under my desk. When I turned the radio on, I started to feel a tingle and a dullish pain in my ankles. When I switched my phone to the 5GHz network I perceived increased radio noise, and noticed a tingling sensation in my hands. Prolonged use seemed to irritate my forearms. It’s entirely possible this is a psychosomatic effect and I’ve kept the radio on based on that assumption. Still, I’m concerned. It feels similar to the effect I feel standing off-axis from my microwave while it’s running 1100W full blast.
Is this in my head? Am I safe to use this radio at full gain? Should I not keep it by my desk?
Radio technology has been in widespread use for over a century. The only health effects that have ever been conclusively demonstrated are due to heating of the tissue. A typical Wifi router with a few hundred mW of maximum power probably won't do much. The LTE transmitter in your phone is considerably more powerful and much closer to your body. Most likely the effects you have seen are entirely psychosomatic.
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.
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.
I have felt an almost imperceptible tingling when I stand off-axis from the my microwave too. I thought it was a figment of my imagination. Based on the experience you shared, it might not be. I don't experience anything like that with my 5Ghz wifi or anything else though.
You are spreading false information. A microwave oven does not "leak" or generate the kind of dangerous alpha particles, beta particles, and gamma rays (ionizing radiation) detected by a Geiger counter.
Is their a decently affordable type of tool for measuring or capturing em radiation in the WiFi frequency range? I suppose I could glean a lot from running a logger on an ESP32 and walking around, but I have to imagine EE folks and scientists have better tools for the job.
... 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.
"Ultimately, the technology may help power rural areas or transmit energy from offshore wind farms, both cases where it’s expensive to build physical infrastructure to tap or feed the grid."
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.
You can have a satellite at low earth orbit taking energy from the sun or even more ambitiously nuclear fusion(like the sun) that may very well be easier to archive in low gravity of near space, then transmit this to a base earth station. It would be near-free in the same sense that the suns energy is near-free.
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.
Yeah, there aren't enough details here to prove the claims. Not to mention, how much power do the "transmitting relays" use. Those sound like they need to be active devices that require a power source. Yes you can siphon off power from the beam, but with all the losses involved it doesn't seem to make sense.
This is AI generated spam. Spam itself is not notable, and soon AI generated spam will not be notable either. But it's interesting to see the beginning where it starts showing up in the wild.
Edit: As several have pointed out... I'm wrong. I was confusing energy with power.
> 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.
Frequency and energy are directly related, the way this is communicated makes sense. Microwaves have a shorter wavelength, higher frequency and are therefore more energetic than the other light mentioned. You're going back and forth between energy and power which aren't the same thing.
Powerlight Technologies does power transmission via lasers, and does it at non-toy power levels (they have demonstrated 1kW delivered @ 1kM). They do both free-space and power over fiber. The main downside to doing it optically is the cost of the system as the focus so far has been on custom tailored systems for use-cases where there isn't any other way to get power.
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.
Unless there's some physical reason you can't run physical conductor there's every reason not to do this.
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.
Fairly scary working around high power radar. Microwaves heat up the "high water content" parts of your body. Eyes, as you mention and also...testicles.
Yes, the person you are responding to was making a joke by playing off the fact that we all would have immediately thought of Great Balls of Fire, and then they subverted that expectation. Ergo, humor.
An electrician working at a Radar station here in Iceland (https://en.wikipedia.org/wiki/Hofn_Air_Station) was stuck there overnight during a snow storm. For some reason he decided to stay in the radar room, probably since it "felt warmer". He was found properly cooked the next day. Not really an interesting story, but since I was probably 6 years old when I heard it it's stuck with me ever since and caused an everlasting fear of high powered radar.
This actually sounds a lot like an urban legend. Especially given that it’s a story you heard in your youth.
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.
Yep... considering the skin effect, any microwave radiation would start heating the outside skin layer first, and it would hurt long before anything inside you was "cooked".
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.
Ha, stories similar to that were going around in the 90's in the RAF. Particularly if you found yourself out in the cold at an RRH up north somewhere...
That's my thought. One of the technical challenges of space elevators is how to deliver power to the climber. Some of the other options are to use lasers and solar panels, or to use the cable itself as a conductor.
(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.)
Your latter concern is covered in the article: "But if it works as intended, the beam won’t ever contact anything but empty air. 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."
“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.
Ignoring all the other reasons this is unlikely to work, 8dB sidelobe level is very easily achieved though. I'm assuming they're using some sort of phased array, where SLL can be designed to <-20dB or more.
Have you ever gone out on a hot day and stood in the sun? There's a big difference between sun and shade. A head with black hair gets super hot, aside from the general heat you feel.
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.
Microwave ovens operate at 2.45 GHz because of frequency management issues - we just can't afford to have jammers all around the spectrum. The first water absorption peak is actually at 22ish GHz.
Any heat which is absorbed causes water molecules to vibrate. Including sunlight. There's nothing particularly special about being broad vs narrow spectrum in this case.
Actually, from my perspective I thought this was a really interesting idea, then wondered why we don’t use it everywhere all the time and figured there must be some cons that have prevented us from doing this before.
Some of the “negative” HN comments gave me exactly the information I was interested in that the article hadn’t mentioned.
Personally i find people who treat everything as positive and refuse to acknowledge fundamental problems just as annoying who view things as utterly negative and only point out problems without trying to find solutions.
Well, okay guys, I'll give you a "solution" since this is proposing to use RF anyway. Instead of doing it entirely wirelessly use a very thin conductor surface wave transmission line (SWTL). That way only one conductor is needed and the RF energy is mostly contained within a wavelength or so of the SWTL (think "inside-out waveguide). The conductor can be very thin, like 28 awg. Or, for spanning larger distance, SWTL mode has been demonstrated on twisted aluminum cord used in normal power lines. It's just a matter of adapting the coaxial to SWTL launcher (sort of cone).
The modern western world loves Safety(TM). This isn't a bad thing. Obviously we don't want people getting killed in industrial accidents all the time. However, as a side effect any platform (HN, Reddit, Twitter, whatever) which quantifies people's opinions is going to tend toward shallow pearl clutching when it comes to topics like this. People realize that when they make some shallow (shallow has the nice side effect of giving you a wide potential audience) comments about GoodThings(TM) like Safety(TM) their virtue score goes up.
So every time some topic comes up, no matter how mundane or niche it is, there will inevitably be tons of people tripping over each other to score cheap virtue points by going after obvious trad-offs. "What about safety", "what about the poors", people ask questions like that even though they already know and don't care about the answer because their lizard brain knows that when they do that the number in the top right corner gets bigger.
You've got the wrong attitude. It's crucial to thoroughly explore a problem space before launching into half-baked "solutions" that risk compounding complexity.
Everyone loves to try and score some cheap virtue points harping about safety but I don't see how a beam between two poles is worse than a live wire between two poles. Whether it's a metal line or not doesn't matter. You touch that space it's not gonna end well. The danger is constant compared to other electrical transmission and there are other benefits. Seems like a net positive so why not try it for niche use cases where its advantages make sense.
I think you have a fundamental misunderstanding of how live wire accidents happen and are prevented.
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.
So sad. If only their team of physicists, engineers, and scientists had done basic internet research. Too bad. I guess they’ll plow ahead and try it out, anyway. Maybe humanity will just accidentally be a better place, despite the extraordinary negativity.
His error is assuming that the people working on this aren't aware of the potential issues and working to resolve them. I mean, if they can't, they won't be able to deploy this system.
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.
Really? Do you think the NZ government is incompetent, Emrod is a scam, and/or PowerCo have not considered these extremely basic issues? The error by OP is assuming everyone involved in this project are morons who have yet to consider even a cursory search of the feasibility of their proposals.
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.
You're making a few of your own assumptions here. I'm op in this thread and yes, I do think this is going to fail because of the physics of it. The free space path loss is always going to lose most of the power (ie, 40-50 dB off the top, and it's the top that matters) for any reasonable dish sizes, freq choice, and distance over 1km.
Why do you think that, though? If the beam is shaped so that it's almost all captured, and there are negligible atmospheric losses due to the frequency range chosen, why should there be high path losses?
No magic at play here. The equations are open for all to explore. We are not breaking the laws of physics. Just flexing them with clever engineering.. just like innovators that came before us. For example, the radiating near field of a 2.4GHz antenna about 8 meters long would extend about 1km.
Surely you do not expect Emrod to discuss in detail the subject matter of its patent applications?
Someone elsewhere in this thread pointed out who the founder (Zvi Kushnir or Greg Kushnir) is, and some of his past.. "endeavours". He's started a new company every year for the past 5 years; including crypto and "psychic consulting" which he is no longer the director of. Luckily New Zealand Companies is open and searchable.
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.
HN people only correct the "false facts" that people (with their professional career of 2 or 3 internet searches perhaps) assume when commenting on a site full of professionals in the field that is covered in each publication... If you feel like debating, having basically "zero experience" in the subject matter, make a post on facebook or twitter and receive attention from people who are at the same level of ignorance as you, and return when you have a professional career and important information to share.
I agree my math was wrong, I am sorry and I have removed it. I should not be commenting on the internet late at night.
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?
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?
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.
It's a very manageable risk (i.e. this isn't like dredging a canal with a nuclear bomb), but high power electromagnetic radiation can hurt you. Not in the 5G-causes-arse-cancer sense, but you could end up at least microwaving some birds.
Maybe not the test, but current high powered microwave transmitters aren't safe to stand in front of. And I assume the production product would be higher power than those.
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.