Ernest Worthman – Energy Harvesting and The Technology of the Future

15 October 2018

Ernest Worthman is the executive editor of Applied Wireless Technology. We discuss energy harvesting – past, present, and future – with a focus on RF technologies

This episode was recorded in October 2018

Yuval Boger (CMO, Wi-Charge, @TheChargeGuy): Hello Ernest and welcome to the podcast.

Ernest Worthman: Thank you very much Yuval, it’s nice to be here.

Yuval: It’s good to have you. So who are you and what do you do?

Ernest: Well, I am Ernest Worthman and I do a number of things. One of which is I am the executive editor of a publication called Applied Wireless Technology, an AGL publication. It talks about basically all of the edge of the envelope segments of wireless RF,  basically, and the peripheral elements that come into it. Things such as the cloud, the edge, security, cybersecurity specifically. A number of items that come with it. Over the years, I’ve worked in a number of different fields. Power and batteries, energy harvesting, some fiber optics, I’ve worked in the semiconductor industry, but my focus has mostly been in RF and RF-related industries. I have a bachelor’s degree in electrical engineering, league member of the IEEE, and a member of the VTS liaison for the IEEE as an officer. I’ve taught, I’ve done a number of things, corporate work, and finally and lastly I also have a consulting practice where I do technical writing for a number of companies from Agilent to IBM, to others.

Yuval:  That’s great, so you’ve been doing this for quite some time. In those years, you’ve seen sort of the wireless data and the cellular revolution come to fruition, be as large as it is today. When you think about wireless power, how would you date wireless power? Is it like the 1980’s of cellular, like 2000? I mean where on the development spectrum do you think wireless power is relative to how cellular was?

Ernest: In the RF arena, wireless charging, or wireless power, and as you say, that can be sometimes used interchangeably, although there are some minute differences between the two. The largest–you know it’s a relatively new industry when it comes to things like cell phones, tablets, mobile devices. The reason for, in my opinion, that it has taken to develop, is because the power factor, the usage by such devices has to be brought down so that the batteries–and the battery technology has to be brought up so that low energy or low power charging has the capacity to make products work well quickly. People aren’t going to sit there and put their tablets on a charging pad or near a power source for 12, 14-15 hours to get a battery charge. So in that sense, it’s still sort of an emerging segment of the industry.

Yuval: Though by the way, this is if you have to put it on a pad. But if energy was somehow plucked out of the air, and you didn’t need to do anything special with your tablet, you just put it on your coffee table or just next to you. While that’s happening it would charge, then charging time probably is less of an issue, than if you have to actually give it up and connect a cable or put it on a pad.

Ernest: That is one of the segments that we’re looking at when it comes to wireless power and wireless charging. However, as we know, the major challenge there is distance. As the device gets moved farther and farther away from the emitting source, the available power drops tremendously with RF.

Yuval: Now in the intro, you mentioned energy harvesting. Would you define that for me and what is your view on where we are with energy harvesting these days?

Ernest: Right. So energy harvesting. It’s not all that new, but it has moved into areas that previously were well outside the wheelhouse because there was no practical way to harvest that energy. One of the advancements that has happened in energy harvesting, is being the ability to develop low power devices that can pick up micro-volts and mili-volts and actually convert them without losses. The key here is without losses. There are a number of energy harvesting segments, there’s medical there are communications, there’s bio-mechanical, there are several others that have been looked at to harvest energy.

One of my favorites is taking energy from kinetic motion in a bone or a joint for example and using that energy to transmit data back to a router or an access point or whatever they want to do. For medical uses, and I’ve looked into that and that’s kind of interesting. But in the RF field, they’ve looked at energy harvesting from antennas. The problem still comes in with the distance. You have to be close to the emitting source or you have to have a lot of sources and you can collect the energy. Either way, it’s a difficult situation until we get down to basically zero loss conversion of captured energy into used energy.

So in that particular sense, we are looking for some very interesting and very new edge of the envelope applications with light or with RF or with motion or with something. Which is one of the things that captured me, Yuval, when I was at the trade show talking with you about that. This is something that I hadn’t seen before, and it’s extremely interesting.

Yuval: Now in your definition, is energy harvesting sort of secondary, a by-product of something else, meaning I have WiFi in my home and if I could put a little sensor that would also pick up some of that WiFi energy so the battery would never need to be replaced. Is that the meaning, or do you look at energy harvesting as a term for the primary reason of getting energy from a source?

Ernest: I think both of those definitions are somewhat correct. I think they are separate fields in some way. When we talk about incidental energy harvesting, and again one of my prime examples is using the kinetic energy that comes from motion to capture that energy, or counter that energy. Whether it be heat, whether it be movement, whether it be gravity. Anyone of those items can use that. On the other hand, there’s big energy harvesting such as windmills, such as solar cells, such as water hydro-power. You’ve got two ends of that energy harvesting to look at when you talk about energy harvesting in general.

Yuval:  One thing I know that you’ve worked on is security with IoT devices, and I was thinking about the analogy with power. If I have power beaming happening at home or the office somehow, how can concerned are you that someone will basically steal my power? That an unauthorized user will just tap into my power source and get free charging that way?

Ernest: That is not, in my humble opinion, as big an issue, as it is with wired data. Again because radiated energy, and we’re talking RF now, is hard to capture beyond a few meters of the source. So if you’re in your house, you’re charging your phone or your laptop, whatever device you decide to use, it would be, I think, very difficult to drain off excess energy from that. The initial power levels, at least at this stage of the game, are still relatively low.

Yuval: I would assume that it would remain low, right? Because if you tried to crank them up, you’re going to run into a whole bunch of safety and health issues. I don’t know of a lot of people who would want to have radio power in their living room.

Ernest: That’s precisely what happens. Plus the FCC regulates all of this. You can’t just put an energy source in your living room as you say, a cell tower, and turn it on. There are all kinds of regulations that prevent that. And that also becomes one of the major challenges in developing any sort of wireless power because of the possible potential, I should say, not possible. Potential damage or issues that arise with any type of electromagnetic radiation. As you know, there’s been discussions for years now of the dangers of cell phones in your ears. While none of that has been proven, there is some circumstantial evidence that long term use over a long period of time consistently does have some negative effects on the human body.

Nobody is really saying it’s bad for you. Probably because the cellular industry would scream bloody murder, but you know there is some tangential and circumstantial evidence that that does happen, although there’s nothing that has been proven. However, just because it hasn’t been proven doesn’t mean it doesn’t exist. Therefore we go back to the issue of saying, “How much power can you have, and how close you need to be for that power, and how long”.

With 5G coming up and if we start talking about millimeter-wave frequencies, 20, 40, 60, 80, 100 GHz. Those frequencies are more likely to produce negative effects on living tissue than the lower frequencies. There are some issues there with power distance. Of course higher frequencies, there are a lot more propagation issues that you deal with, so that hasn’t been studied yet, but I think it’s coming up, and a way to do that. So when you’re working with wireless power, you can either use a directed source such as a laser beam, or you’re kind of stuck with scattered energy and trying to capture it in the best physical position you possibly can.

Yuval: And therefore would you think that a directed source a point-to-point transmission like what we do in Wi-Charge with an infrared laser is promising in that regard? No incidental energy exposure and also not a lot of variation for power versus distance. I mean if you think about a laser pointer, you could get farther and farther away from a wall and still have a very tiny dot on that wall. So you don’t have the same level of efficiency loss when the distance increases. What’s your view on that?

Ernest: When I met you, and one of the reasons I became interested in what you’re doing was because there is a huge market for wireless charging. And the solutions at this point are not very–there’s not a lot of solutions out there. So when I saw what you were doing, I thought it was very interesting. And when you explained to me how this works, I said “Yes. This is the technology of the future.” Immediately my little brain started thinking about, “Well. Let’s say you’re in your house, lets say you have wireless speakers, wireless light sockets, wireless appliances.”

By having a source that can direct energy with a laser, which as you explained to me, you don’t lose any power in the transmission because the beam is so tightly coupled and so narrow. Then you’ve got this interesting scenario, where you might have in each room, an emitter. A laser emitter, and it might be able to, though of course, a number of electronic connections and communications back and forth, know what’s going on with each of these devices. Supply power as it needs it, and it wouldn’t have to be a constant source. If you’d deliver a lot of power, fast charging, high capacity batteries, or even smaller batteries that could be charged, pulse every so often, I mean to me that’s a very exciting technology that I hadn’t heard of before and I like it.

Yuval: I think the other thing that we like about infrared, is in a sense, it’s natural light. I mean 50% of the sun’s energy is infrared so you and I and our ancestors have been living in an infrared rich world for eons. As opposed to RF which is sort of man-made radiation. Yes, there are some cosmic rays in the galaxy right? But there’s not a whole lot of natural RF going on down here.

Ernest: And that is correct. You’re right about that. We’ve been trying to harvest light for a long time through photocells. The visible light spectrum, more or less, well the complete light spectrum. While photocells have been an attempt to do that for many years, it just doesn’t work well because the light is too scattered. Photocells are going to be a quantity over power distribution issue for the rest of our lives. Unless we can find some way to, and I don’t see this happening, to take that energy and get it either concentrated or closer to it’s source. So portable cells is not particularly, it has some great applications but it has a very limited technology base that you can work with. And I think, what they’re now 20% efficiency over the last 10-15 years, they’ve gone up 20%. We’re a long way on that one, and I don’t think that’s ever going to become a major source of energy without miles and miles of cells and all kinds of other technology thrown in there.

So concentrated light just seems to be a really good solution for that. And this is not, I’m not saying this because this is what you do, but I’m saying this because you interested me in something that I think is a really good technology and I have no dog in this fight so to speak. I’m an RF guy, but I find it as a real potential solution to a lot of things happening in today’s world, especially in low power, high-frequency stuff that needs power. And how to get the power, and with the internet of everything and anything as I like to call it, the IoX, there’s going to be billions of devices out there and somehow we’ve got to power all those. And they’re not always going to be within range. Some of these devices may be a kilometer, 2, 5, 10, 15 km out of range. I suspect that this kind of focused beam energy delivery might be a really good solution for something like that. Especially if its the top of the mountain.

Yuval: When you think about all these applications, powering the smart speakers at home or charging IoT devices on a building or a street, or charging in a car beyond just putting your phone on a t-charger, if you had to venture a guess, where would you see the market develop for us then? And we can set a date for three years out too, in 2021 to see how well you did.

Ernest:  You know what, that would be fun to do coming back. Frankly, I think the number one application for this would be the home. Smart Home. Secondly, I think Smart City would be a potential for this. Although most city centers are attached to devices that have power, I’m not sure how that would work, however, there’s got to be a lot of areas where there really isn’t power available. That would be the second guess. The third guess would probably be the vehicle, although vehicles again tend to have the power to be tethered to relatively small contained areas so wiring to a vehicle isn’t that critical. Now the fact that you have a design that follows the device and continually keeps the beam and charge in contact with that device is a very unique approach to it. You don’t have to sit there and spray energy everywhere and hope you hit something. So any place that has a rather contained area that has a need for this, I think is a great candidate. Even probably transportation, buses, trains, airplanes especially. There’s no power on airplanes. This would be a great solution.

I think that it’s going to take maybe, well it depends on what happens in the next year or two in certain elements with the IoX especially in 5G, but I think we’re a couple-three years out before this becomes really visible to people who realize that, “I’ve got all these devices, I need to do something with it”. And I think the answer to that question is going to be, the more devices people have, the faster this is going to take off.

Yuval:  And as we start coming to a close, what do you think the role of standards here is? How important are they? Is it first important to just show that you can actually deliver useful power levels safely to home devices and then rally industry players around standardizing it? Or should the standard work come first?

Ernest: You know I believe that it could be a partnership. I think what we have to do, and I know this is true in the RF industry. We have to show the standards body what we can do. Once we show the standards bodies what we do, then we can form consortia and we can form working groups and we can do all of that stuff to help develop the standard. And of course, the standards have to be guided by the industry players that really know what they’re doing. So is it a chicken and an egg? Not necessarily. I think it’s more of a lock-step. The technology gets developed, it gets shown, it gets proven, even in its infancy stages. And from a mathematical perspective, safety perspective, then we talk to the standards about it and say, “We’ve got this, how do we make this happen as I said.”

Yuval: That sounds great. So Ernest, how can people get in touch with you to learn more about your work and what you’re doing?

Ernest: So there’s a couple of ways. I’m happy to put up my phone number. 303-290-9700, my email is ernest_worthman@ieee.org, and also I’m on LinkedIn, and basically, if somebody wants to just google my last name out there, I come up way too often. So those are the best ways. Any way you want to get in touch with me let me know.

Yuval: That’s excellent. Well Ernest, thank you so much for coming on the podcast today.

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