6 ms·

The key point here is that it has a 60% efficient. The question is, why is it important? Well in the later part of Afghanistan war, significant time, money, a

The key point here is that it has a 60% efficient. The question is, why is it important? Well in the later part of Afghanistan war, significant time, money, and lives were spend shipping diesel around. If you can avoid that, you can save a shit tonne on logistics.

Terry_Roll 5y ago
So like all technological achievements, things will improve so the amount of power that can be transmitted will increase and the distance will increase. At some point in the future it might become feasible to beam the energy down from a Low Earth Orbiting Satellite, which would transfer logistical costs into the preemptive side of accountancy instead of reactionary accountancy, but if they could do this from a LEO, then perhaps its also become a bit of a non ballistics weapon which may not be covered/restrained by current international agreements.
- FredPret 5y ago
  There is a power plant in Sim City that operates on this principle. Would be cool to have a nuclear reactor in orbit!
  - Terry_Roll 5y ago
    Tesla built the means to transmit power in the early 1900's. https://en.wikipedia.org/wiki/Wardenclyffe_Tower https://en.wikipedia.org/wiki/Wardenclyffe_Tower https://en.wikipedia.org/wiki/Wireless_power_transfer#History https://en.wikipedia.org/wiki/Wireless_power_transfer#Histor... I would imagine alot of Radio transmitting knowledge would be useful in this domain of knowledge.
    - uuyi 5y ago
      Ex RF engineer here. No he didn’t. He was a con man.
      - Terry_Roll 5y ago
        I thought he had actually built that tower, tv documentaries portray him as a genius who invented stuff but wasn't commercially successful.
        uuyi 5y ago
        It was built but that’s not the real story. Ignore the TV documentaries. The real story was the tower was built for information not power delivery. But Marconi got there first and made it irrelevant. Tesla decided to repurpose the thinking around some fanciful bullshit for power delivery to pay off all the money he’d borrowed to build it. This cycled into non delivery, because quite frankly it didn’t work, and he ended up bankrupt, living in a hotel for free after giving the hotel owner a “death ray” for security. This turned out to be some primitive measurement device. Tesla did a lot of good work on AC power delivery however. But that was it. I’d rather remember him for this than the legendary bullshit.
- DennisP 5y ago
  Most solar power satellite designs put the sat in geostationary, which simplifies things dramatically. It makes the power density low enough at ground level that birds can fly through the beam without harm. The receiver has to be several square kilometers but it's mostly antenna wire. The transmitter would be a phased array antenna, and getting even that much focus would require a reference signal transmitted from the ground station.
  - walrus01 5y ago
    In my opinion by the time you're going to the trouble to clear a flat plot of land and get into the construction project of erecting a several square km sized receiver array, you might as well just go whole-hog on commodity ground mount photovoltaics on the same area of land. And totally eliminate the cost of the satellite. There's plenty of contractors out there who specialize in building such things from existing COTS systems/subsystems and components. Look at the specifications and size of some of the large ground mount PV systems in China and India. Margins are very thin in this business and very competitive on $ per kWh feed-in tariff rates paid to contracted systems. The construction process has been optimized to nearly as good as it can get now. Labor is a major cost.
    - DennisP 5y ago
      And add the cost of batteries.
      - walrus01 5y ago
        doesn't necessarily have to have batteries, as in many common installations, daytime PV is used to flatten the curve of fuel consumed by regional coal, gas, other fossil fuel power plants servicing the daytime peak of load demand. Conveniently enough in many places with hot weather when the peak of load demand is occurring mid afternoon with everybody's air conditioner running, the PV system is also performing at its best. Or can be connected to something long distance similar in tech to the pacific HVDC inter-tie to move power long distances to where it's needed, or can be used to pump water uphill in a nearby pumped-storage hydroelectric system.
toephu2 5y ago
Actually it's only 1.8% efficient. From the YouTube comments: Video carefully avoids to state that the overall efficiency of the system is 1.8%. Input power was 91.2kW at the TX antenna, out of which 1.65kW was produced at the receiving side. https://ieeexplore.ieee.org/mediastore_new/IEEE/content/media/9171629/9673801/9662403/roden.t2-3130765-large.gif https://ieeexplore.ieee.org/mediastore_new/IEEE/content/medi...
hilbert42 5y ago
Whilst 60% is efficient and it's an excellent figure don't be fooled by the hype. I reckon what they've said in the the video is outrageous in that much of it is deceptive and misleading in the extreme. Let's briefly look at some of the issues: 1. We need to carefully look at where that efficiency happens and then examine every place where loss of energy can occur, especially those that aren't stated. Let's take a brief look at some of the more obvious ones: 2. Conversion of energy into power suitable for generating microwaves at the transmitter. On earth, and assuming direct connection from the power grid, we need to consider losses in the power transformers and power supply or switching power supply, these days efficiency can be very high perhaps even 90% or more. As this equipment will be used primarily for military use, it would likely couple with diesel motor/generators suitable for use in the field, if so then I'd be surprised if the combo was more than 35% efficient at best (someone who knows up-to-date specs on these units correct me if necessary). If the unit is ultimately used in space then the conversion efficiency of its solar panels must be taken into account. As far as I'm aware no solar cell has ever reached 60% or over—even the best GaAs ones (from memory, this 60% figure would exceed theoretical 'quantum efficiency' figures). 3. Assuming no other loss at the power supply end (such as offline batteries, which are a distinct possibility in the field in military use) then we have to take the efficiency of microwave sources into account. I've not up-to-date figures on the latest 10GHz generators so I'd be guessing these figures, suffice to say that until recently generating microwaves was comparatively inefficient (unless magnetrons are used and they have messy and inconvenient HV power requirements). 4. Next comes the waveguides, antenna horn and focusing unit and the antenna (these, if optimized, could be quite efficient). 5. Now comes the path loss between transmitter and receiver. Exactly what that is remains to be seen. I've worked with microwaves and I can assure you that it is dead easy for the antennas be slightly off alignment and you receive almost no signal. For this scheme to work efficiently there would have to be some kind of efficient control system (servo/feedback, etc.) that keeps the TX and RX antennas in precise alignment. Moreover, at 10GHz a storm or a heavy rainfall downpour could kill the circuit altogether (I've actually seen this happen to the extent that only over a path of a half dozens or so miles that not only the fade margin, normally >30dB, on microwave links was exceeded but also the signals fell so low that the circuit was actually lost. Moreover, for reliability, two microwave links were run in parallel and both circuits failed for some 5 or 6 minutes until the rain cleared). 5a. Now the killer bit: as mentioned, commercial microwave links have huge fade margins to protect against variations in atmospherics and objects—planes etc., blocking the way. These links have what is known as AGC—Automatic Gain Control—to keep signals level. That cannot apply in power transmission; in practice, even a temporary path loss of 6 - 12dB (which could easily be expected) would essentially be catastrophic, that is effectively kill all received power at the receiver (they'd want to have pretty good battery backup and often in military operations that's not always possible, extra weight etc.)! 6. Now comes the horror bit (this could also apply to the generation of the microwaves at the transmission end). That is, the rectification of microwaves at the receiving end will generate considerable RF hash and noise. To be efficient, the diodes rectifying the incoming RF would have to have an f(t) of well in excess of that frequency and heaven help anyone operating a microwave receiver within many miles of the receiver (radio astronomers for instance). As the rectification diodes have to be near or on the antenna for efficiency, screening them to stop them radiating locally generated crap everywhere would be a near impossibility—remember your Fourier lessons, you're chopping sine waves up to get DC and that means harmonics—the more efficient the process the more noise generated! Any attempt to filter the hash and noise generated by the diodes would further reduce efficiency. This is the sort of scenario that spectrum managers and planners have nightmares about. Whilst this isn't quite the same, here's an example that illustrates what can happen. I had an Amateur Radio friend who used to do moonbounce on 432MHz and he'd often complain to me that various LED lights (i.e.: diodes) in his neighbors' possession would interfere with his incoming reception to the point where on occasions he'd have to abort the exercise. Now keep this in mind, he raised this matter with me over 10 years ago when LED lighting was far less common that it is today. Face the facts, much of this pronouncement is little more than spin. Likely the principle reason the video was made was to keep their funding masters happy. Little of it will fool the technical cognoscenti. Also keep in mind that all 'niceties' are off during military conflicts, interference to services other than to the military's own communications equipment would likely be irrelevant (as we saw in WWII, the military was the principal user of spectrum, what it wanted it got). As for a permanent space port 'broadcasting' power to earth the idea is ludicrous—that is, until thousands of questions about likely problems have been asked and that genuine engineering solutions for them are actually found. Seems to me their PR department has taken a leaf from the wordbook used by social media and politicians—that's the one that redefines the word 'fact'!
powersnail 5y ago
The article mentions rain. What about sandstorms or snow? Is microwave heavily hindered by any other climate adversities?
walrus01 5y ago
based on terrain and other logistical challenges in Afghanistan I bet you $5 that sending a 20' ISO container packed with solar panel/ground mounting/advanced battery system would accomplish a whole lot more kWh per month than a "power over microwave" system from some central point to regional FOBs. 1.0km and 60% efficient is not very impressive. various parts of the DoD are very interested in things like hydrogen fuel cell generators, more advanced/efficient diesel generators, prepackaged photovoltaic power systems, etc. they fund and buy prototypes all the time. they're well aware of the problem in transporting liquid fuel around.
- CyanLite2 5y ago
  Yea, seems like easier technology is out there for real battle zones. I think this wireless power idea would be best in disaster scenario areas on the US mainland after weather events. They could pre-ship out the dishes to EMA agencies around the country. Quickly deploy in a few hours and re-power areas that have been destroyed by hurricanes/tornadoes/wildfires until the electrical grid is re-established or a ISO container can be sent.
  - TomK32 5y ago
    That was my first thought as well, but, when you are able to deploy this transmitter, you are most likely also able to deploy a huge generator and some big generator trucks can deliver a thousand times more energy than this wireless thing.
- manquer 5y ago
  Plenty of applications at 1 km and 60 % are possible, many devices are small and becomes easier to operate around a outpost if powering them wasn’t impractical with wiring , or have short battery lives Recharging drones is a good example, depending on how compact the receiver can be developed you could even integrate into the drone and keeping it up continuously . There are bots like the stuff Boston dynamics builds that can work in say a minefield or other hostile environments for more time or continuously if you could be beam power to them. You could use it to recharge cctv and other perimeter monitoring system sensors rapidly in a new output where you haven’t time to do wiring , or the outpost is temporary . In a urban environment you could to keep you active EM emitting equipment like radar / satellite dishes equipment 1 km away and be safer from missile strikes. Sure it would be nice to have 100s kW at 10s of km but a kW is plenty of power for a lot of devices and there are solid applications

Terry_Roll 5y ago

So like all technological achievements, things will improve so the amount of power that can be transmitted will increase and the distance will increase. At some point in the future it might become feasible to beam the energy down from a Low Earth Orbiting Satellite, which would transfer logistical costs into the preemptive side of accountancy instead of reactionary accountancy, but if they could do this from a LEO, then perhaps its also become a bit of a non ballistics weapon which may not be covered/restrained by current international agreements.

FredPret 5y ago
There is a power plant in Sim City that operates on this principle. Would be cool to have a nuclear reactor in orbit!
- Terry_Roll 5y ago
  Tesla built the means to transmit power in the early 1900's. https://en.wikipedia.org/wiki/Wardenclyffe_Tower https://en.wikipedia.org/wiki/Wardenclyffe_Tower https://en.wikipedia.org/wiki/Wireless_power_transfer#History https://en.wikipedia.org/wiki/Wireless_power_transfer#Histor... I would imagine alot of Radio transmitting knowledge would be useful in this domain of knowledge.
  - uuyi 5y ago
    Ex RF engineer here. No he didn’t. He was a con man.
    - Terry_Roll 5y ago
      I thought he had actually built that tower, tv documentaries portray him as a genius who invented stuff but wasn't commercially successful.
      - uuyi 5y ago
        It was built but that’s not the real story. Ignore the TV documentaries. The real story was the tower was built for information not power delivery. But Marconi got there first and made it irrelevant. Tesla decided to repurpose the thinking around some fanciful bullshit for power delivery to pay off all the money he’d borrowed to build it. This cycled into non delivery, because quite frankly it didn’t work, and he ended up bankrupt, living in a hotel for free after giving the hotel owner a “death ray” for security. This turned out to be some primitive measurement device. Tesla did a lot of good work on AC power delivery however. But that was it. I’d rather remember him for this than the legendary bullshit.
DennisP 5y ago
Most solar power satellite designs put the sat in geostationary, which simplifies things dramatically. It makes the power density low enough at ground level that birds can fly through the beam without harm. The receiver has to be several square kilometers but it's mostly antenna wire. The transmitter would be a phased array antenna, and getting even that much focus would require a reference signal transmitted from the ground station.
- walrus01 5y ago
  In my opinion by the time you're going to the trouble to clear a flat plot of land and get into the construction project of erecting a several square km sized receiver array, you might as well just go whole-hog on commodity ground mount photovoltaics on the same area of land. And totally eliminate the cost of the satellite. There's plenty of contractors out there who specialize in building such things from existing COTS systems/subsystems and components. Look at the specifications and size of some of the large ground mount PV systems in China and India. Margins are very thin in this business and very competitive on $ per kWh feed-in tariff rates paid to contracted systems. The construction process has been optimized to nearly as good as it can get now. Labor is a major cost.
  - DennisP 5y ago
    And add the cost of batteries.
    - walrus01 5y ago
      doesn't necessarily have to have batteries, as in many common installations, daytime PV is used to flatten the curve of fuel consumed by regional coal, gas, other fossil fuel power plants servicing the daytime peak of load demand. Conveniently enough in many places with hot weather when the peak of load demand is occurring mid afternoon with everybody's air conditioner running, the PV system is also performing at its best. Or can be connected to something long distance similar in tech to the pacific HVDC inter-tie to move power long distances to where it's needed, or can be used to pump water uphill in a nearby pumped-storage hydroelectric system.

toephu2 5y ago

Actually it's only 1.8% efficient. From the YouTube comments: Video carefully avoids to state that the overall efficiency of the system is 1.8%. Input power was 91.2kW at the TX antenna, out of which 1.65kW was produced at the receiving side. https://ieeexplore.ieee.org/mediastore_new/IEEE/content/media/9171629/9673801/9662403/roden.t2-3130765-large.gif https://ieeexplore.ieee.org/mediastore_new/IEEE/content/medi...

hilbert42 5y ago

Whilst 60% is efficient and it's an excellent figure don't be fooled by the hype. I reckon what they've said in the the video is outrageous in that much of it is deceptive and misleading in the extreme. Let's briefly look at some of the issues: 1. We need to carefully look at where that efficiency happens and then examine every place where loss of energy can occur, especially those that aren't stated. Let's take a brief look at some of the more obvious ones: 2. Conversion of energy into power suitable for generating microwaves at the transmitter. On earth, and assuming direct connection from the power grid, we need to consider losses in the power transformers and power supply or switching power supply, these days efficiency can be very high perhaps even 90% or more. As this equipment will be used primarily for military use, it would likely couple with diesel motor/generators suitable for use in the field, if so then I'd be surprised if the combo was more than 35% efficient at best (someone who knows up-to-date specs on these units correct me if necessary). If the unit is ultimately used in space then the conversion efficiency of its solar panels must be taken into account. As far as I'm aware no solar cell has ever reached 60% or over—even the best GaAs ones (from memory, this 60% figure would exceed theoretical 'quantum efficiency' figures). 3. Assuming no other loss at the power supply end (such as offline batteries, which are a distinct possibility in the field in military use) then we have to take the efficiency of microwave sources into account. I've not up-to-date figures on the latest 10GHz generators so I'd be guessing these figures, suffice to say that until recently generating microwaves was comparatively inefficient (unless magnetrons are used and they have messy and inconvenient HV power requirements). 4. Next comes the waveguides, antenna horn and focusing unit and the antenna (these, if optimized, could be quite efficient). 5. Now comes the path loss between transmitter and receiver. Exactly what that is remains to be seen. I've worked with microwaves and I can assure you that it is dead easy for the antennas be slightly off alignment and you receive almost no signal. For this scheme to work efficiently there would have to be some kind of efficient control system (servo/feedback, etc.) that keeps the TX and RX antennas in precise alignment. Moreover, at 10GHz a storm or a heavy rainfall downpour could kill the circuit altogether (I've actually seen this happen to the extent that only over a path of a half dozens or so miles that not only the fade margin, normally >30dB, on microwave links was exceeded but also the signals fell so low that the circuit was actually lost. Moreover, for reliability, two microwave links were run in parallel and both circuits failed for some 5 or 6 minutes until the rain cleared). 5a. Now the killer bit: as mentioned, commercial microwave links have huge fade margins to protect against variations in atmospherics and objects—planes etc., blocking the way. These links have what is known as AGC—Automatic Gain Control—to keep signals level. That cannot apply in power transmission; in practice, even a temporary path loss of 6 - 12dB (which could easily be expected) would essentially be catastrophic, that is effectively kill all received power at the receiver (they'd want to have pretty good battery backup and often in military operations that's not always possible, extra weight etc.)! 6. Now comes the horror bit (this could also apply to the generation of the microwaves at the transmission end). That is, the rectification of microwaves at the receiving end will generate considerable RF hash and noise. To be efficient, the diodes rectifying the incoming RF would have to have an f(t) of well in excess of that frequency and heaven help anyone operating a microwave receiver within many miles of the receiver (radio astronomers for instance). As the rectification diodes have to be near or on the antenna for efficiency, screening them to stop them radiating locally generated crap everywhere would be a near impossibility—remember your Fourier lessons, you're chopping sine waves up to get DC and that means harmonics—the more efficient the process the more noise generated! Any attempt to filter the hash and noise generated by the diodes would further reduce efficiency. This is the sort of scenario that spectrum managers and planners have nightmares about. Whilst this isn't quite the same, here's an example that illustrates what can happen. I had an Amateur Radio friend who used to do moonbounce on 432MHz and he'd often complain to me that various LED lights (i.e.: diodes) in his neighbors' possession would interfere with his incoming reception to the point where on occasions he'd have to abort the exercise. Now keep this in mind, he raised this matter with me over 10 years ago when LED lighting was far less common that it is today. Face the facts, much of this pronouncement is little more than spin. Likely the principle reason the video was made was to keep their funding masters happy. Little of it will fool the technical cognoscenti. Also keep in mind that all 'niceties' are off during military conflicts, interference to services other than to the military's own communications equipment would likely be irrelevant (as we saw in WWII, the military was the principal user of spectrum, what it wanted it got). As for a permanent space port 'broadcasting' power to earth the idea is ludicrous—that is, until thousands of questions about likely problems have been asked and that genuine engineering solutions for them are actually found. Seems to me their PR department has taken a leaf from the wordbook used by social media and politicians—that's the one that redefines the word 'fact'!

powersnail 5y ago

The article mentions rain. What about sandstorms or snow? Is microwave heavily hindered by any other climate adversities?

walrus01 5y ago

based on terrain and other logistical challenges in Afghanistan I bet you $5 that sending a 20' ISO container packed with solar panel/ground mounting/advanced battery system would accomplish a whole lot more kWh per month than a "power over microwave" system from some central point to regional FOBs. 1.0km and 60% efficient is not very impressive. various parts of the DoD are very interested in things like hydrogen fuel cell generators, more advanced/efficient diesel generators, prepackaged photovoltaic power systems, etc. they fund and buy prototypes all the time. they're well aware of the problem in transporting liquid fuel around.

CyanLite2 5y ago
Yea, seems like easier technology is out there for real battle zones. I think this wireless power idea would be best in disaster scenario areas on the US mainland after weather events. They could pre-ship out the dishes to EMA agencies around the country. Quickly deploy in a few hours and re-power areas that have been destroyed by hurricanes/tornadoes/wildfires until the electrical grid is re-established or a ISO container can be sent.
- TomK32 5y ago
  That was my first thought as well, but, when you are able to deploy this transmitter, you are most likely also able to deploy a huge generator and some big generator trucks can deliver a thousand times more energy than this wireless thing.
manquer 5y ago
Plenty of applications at 1 km and 60 % are possible, many devices are small and becomes easier to operate around a outpost if powering them wasn’t impractical with wiring , or have short battery lives Recharging drones is a good example, depending on how compact the receiver can be developed you could even integrate into the drone and keeping it up continuously . There are bots like the stuff Boston dynamics builds that can work in say a minefield or other hostile environments for more time or continuously if you could be beam power to them. You could use it to recharge cctv and other perimeter monitoring system sensors rapidly in a new output where you haven’t time to do wiring , or the outpost is temporary . In a urban environment you could to keep you active EM emitting equipment like radar / satellite dishes equipment 1 km away and be safer from missile strikes. Sure it would be nice to have 100s kW at 10s of km but a kW is plenty of power for a lot of devices and there are solid applications