 You're probably all familiar with this picture. This is one of the most overused pictures that's taken. It's basically a map of, I mean, it's a picture of where you have light. And it's essentially a map of energy consumption in the world, which is also a, you could say it's a map of economic activity in the world. Now, the problem with this picture is that it is not real. At no instant in time, it looks like this. Well, first of all, half of the earth usually is the day, and you have night only at half of the time. And it's all usually covered with clouds. And that's important, and that has a significant impact. Because I guess everyone agrees here that energy is one of the most pressing challenges of our time. And I would argue that there are different aspects to the challenges associated with the energy. It is not just the production. In fact, if you look at solar energy, the amount of solar energy that you can generate by covering a small fraction of the surface of the planet with solar panels is sufficient to cover us and way beyond what our predictions are over time. So it's not a question of generation. It's more a question of generating and being able to use it where you need it. So the question really, and that's what really leads to the question of storage and why people spend a lot of time and energy on storage, trying to store batteries and things of that sort. How do you store the energy? Because you can generate solar energy. That's not a problem. So with that mindset, we are looking at Caltech. What we are looking at is a very radical potential solution for this problem that's based on essentially an idea. The original idea is not very new. It was, in fact, it was first discussed in a short story by Isaac Asimov. Called The Reason from 1941. So Asimov, in his story, talks about the situation, the space station, whose primary purpose is to collect solar energy and transfer it to Earth using microwave. And that's exactly what you're talking about. The idea here to put solar panels and put photovoltaics in space and transfer this energy to Earth using microwave signals. So that's the idea of this project. Now, we would say, why on Earth would you want to do that? Why don't you put the solar panels on the ground? Now, think about it this way. Remember the picture we just saw? That picture showed you something that was not real. So is a picture that shows the entire planet during daytime. Now, in fact, in space, you have eight times more solar power available to you because of the fact that you're not subject to the tyranny of day and night and the climate, the cloud covers. So you have eight times more power for the same area that you put in space. And if you can transfer this energy efficiently to ground, you will do two things. You will make it more economical. But more importantly, if you can do this transfer dynamically and send it where you need it, you will have dispatchable energy. So you will also deal with the problem of transmission of the energy. And those are the two things that are very essential to this thing, making dispatchable energy, sending the energy where you need it, when you need it, as well as doing it at a high efficiency. Now, and the way to think about it, the way to do it is, so there's a little bit more detail view of how this will look like. You are thinking about putting these satellites in flying information. We'll talk a little bit more about in details of this. In space, potentially in your stationary orbit. And they absorb the solar energy and they convert it to electrical energy. And that electrical energy is converted to microwave energy and transmit it down to the surface of the planet. So this is, and how do you recover it? From the surface, you will have different ways of recovering it. You can have fixed stations, which basically you can recover this energy, and send it to the grid, and you can augment them if you want with terrestrial solar energy, if you will. But more importantly, you can also have portable units that can recover this energy from the surface. And use that for local powering of places where there is no infrastructure for transfer of energy. So this space-based power station, if you will, a lot of people have thought about it. And what really makes it possible is realizing that there are challenges associated with this, and how do we go about dealing with these challenges. So we have a three-pronged approach. It's a three group, basically, that we are collaborating together with two of my colleagues, Professor Harry Atwater and Professor Sergio Pellegrino. We are coming at this problem with three different sets of expertise and try to solve it. The key to this thing is to make it such that it can be done in an effective, cost-effective, robust, and efficient fashion that's safe. So those are the key questions. So one question about it is that, how do you transfer this power to the earth? How do you deal with this? The power transfer, we talked about dispatchability. You want to be able to send it where you need it. And it really goes back to a concept that's presented in this animation, which is the concept of interference. This is a simple concept. If you go on a pond and start having two things going up and down and creating waves, what you see is that there are regions where the energy is more concentrated, for instance, in this case going straight up. And you can see these troughs, these regions in the blue, where there's very little energy. So at some places, the waves interfere, if you want to talk more technically, constructively and in some regions, destructively. Now, if you take this concept and expand it to multiple sources, what you can do by controlling the timing of this thing, if you can get the timing of this. So this is now eight sources in this case. And what happens is that you will see that most of your energy is going upward. So by creating these sources whose timing are synchronized, you can control the energy flow. And this is a concept known as phase array. So this idea allows you to, by controlling the timing, focus the energy in one direction. But what it does, it's even better than that. What it does, it allows you to not only create these beams of energy, but also steer them, turn them in different direction. And this is what you need because this is very powerful. Timing is everything here, obviously, because like in a lot of other places. But what it does, it allows you to concentrate the energy in a different direction and electronically steer it. Now, beauty of electronic steering is that there are no mechanical movement in space, there's no need for mechanical movement. And what that does makes this very versatile in terms of where you can send your energy. Now, of course, being an academic, if you wanted to have fun. So this is something that's a quality of wave, electromagnetic or waves on the pond. So this is an example of a wave you can see on your right-hand side. What you see, you can see a wave front that's propagating. And the way we did it, by basically controlling, giving everyone a number and basically going one, two, three, four, five, six, seven, eight, nine, ten. And everyone was kind of creating their contribution to the wave. And this collection of contributions creates a wave that travels in a desired direction. So now, with that, the question is, okay, so that sounds interesting, but what are the challenges? Why haven't people done this before? If it was first conceived this concept in 1941, why haven't people done it before? There are several challenges that are very significant. The first one is the cost. And as Fiona mentioned earlier, cost in space for satellite system is really almost equivalent to mass. You really are limited by the launch cost when you want to put things in space. Because we haven't found really effective ways, better than rockets, which are very inefficient if you think about them, of putting things in orbit. So if you want to make something low cost, it has to be very, very light. Extremely light, that's by far the thing that makes a difference. And that's one of the things that we believe our system is very different because it's very modular, and I'll show you what I mean by modular exactly. And lightweight based on technologies that enable that. Second thing is that you want to make sure that it's robust. You're putting things in space. Repairing things in space is not very easy. It can be done, but you've all heard about repairing the space telescope, Hubble telescopes and all those things and how much effort goes into something like that. So you want to make sure that it's robust in such a way that if a part of it fails, the entire system doesn't. And that again goes back to modularity. It needs to be efficient. The power transfer efficiency needs to be high from space to ground. And it has to be safe for people on the ground. And all of these things are things that we are considering and we are actually trying to implement. So the enabling technologies, one of the enabling technologies for this, the chart you will see on your right, essentially is something that shows the growth of the integrated circuits, the chip technology. This is real data. What you see is the number of transistors, which is the functional unit of electronic systems. On a single chip over the years. And you can see that the first ones were in the couple of thousands. This is the first microprocessor that Intel built. And over that period of about 45 years, we have gone to a point that each chip contains more transistors that there are people on this planet. And unlike all the people on this planet, every single one of them works. For the entire chip to work, that's an absolute necessity. And essentially you're building ultra cities on a penny. And what you see on the left hand side is I put one of these chips. You can hardly probably see it. It's a tiny, tiny thing on the scale. And what you see is that you see that it's so lightweight. It's 8.5 milligrams. So that's very important to what you are trying to do. Because there's a lot of electronics, a lot of processing that needs to be done for these systems to work. And each one of these units that I will show you shortly will have to have all of that functionality. So that's what we are doing, integrating all of that. Now this is what we call, you can think about it as a LEGO unit, the building block. We call it a tile. This is a 10 centimeter by 10 centimeter unit that absorbs the solar energy. What you will see is that on the right hand side, you will see that there are reflectors, parabolic reflectors concentrate the energy on a very thin layer of photovoltaic to make it lightweight. That DC power is converted to microwave power and transmitted from the other side. And this basically, and what I will pass around here, is a prototype. Or you can think about it as a mock-up of that to give you a sense of the mass of the system. You can go ahead and pass it around. And what this is, really, the entire system is built out of it. So what you see here is a hierarchy of the system. So on the left hand side, what you see is the 10 centimeter by 10 centimeter, that tile that you are carrying. And that tile, actually, if you look at it carefully, you will see in the middle there's an integrated circuit. On the back side, there's a radiator. And the photovoltaics, you will see thin strips on the top. Black strips, those are photovoltaics. So that contains the entire functionality of this thing. And those tiles come together to form what we call panels, which are about two meters on the side. And they go together to form a module, which is about 60 meter by 60 meter. And the modules are independently flying units. And you put a collection of these things in formation, flying information in space. And that forms the entire system that's about three kilometers by three kilometers. Now to give you a sense of scale, this is something that you are holding in your hands right now. The tile, if I switch to stand on it, that's the size it would be. I mean, that's the panel, I'm sorry. And then the module that gives you a sense of scale. And the entire system would be about the width of the island of Manhattan. So how do you send this in space? Now these are designed, structures are designed so that they're basically an origami system. So they are folded and rolled in such a way to turn it into a cylinder. So each one of those 60 meter by 60 meter modules becomes a cylinder that's about one by three meters and weighs about 135 kilograms. So it's extremely lightweight and it deploys in space. So this allows you to launch it in a cost effective fashion. Now, and the way they will formation flies, so basically they will be in space. You want to make sure that they are facing the sun to collect the maximum amount of energy. Because you really want to use that 24-7, 365 availability of the solar energy in space. And that's what they're trying to do. And when they basically are in space, they would do formation flying. They would be basically going around and collecting the solar energy and beaming it constantly. And that electronic steering that we talked about allows you to dynamically and constantly focus the energy where you need it in a very predictable fashion. Now, this is a picture of what you're holding in your hand or another version of that. And this shows the mass. You can feel that it's pretty lightweight. It's about 1.5 grams, a little bit over 1.5 grams. And the one that you see on the left-hand side is a eurocent. It's about 2.3 grams. And if you take a US penny, it's about half the weight of the mass of this tile that we are looking at. It's about half of a US penny, depending on which year you pick. It can be even like about a third. They used to be copper and now they're going to zinc and aluminum and things of that sort. Anyway, so what that shows you is a sense of what makes it possible to think about these kind of solutions. And of course, things like this don't happen in vacuum. They are usually done by groups of people. And it's a work of a group of people that makes this possible. But when you have something like this, it makes it possible to think about what we call a space-based utility plus, where you actually have the ability to power multiple different locations simultaneously. And this is particularly relevant in places that don't have the infrastructure for power. Sending the power down where you need it and deploy these receiving stations on the ground that can recover that and make it possible to send power to different locations, have it where you need it, when you need it, and as much as you need. And by doing that, you can think about ways of enabling the transmission of power to various locations on demand. And with that, I'd like to just leave you with a thought. It's not that it's a done deal. It's that now the technology is at a point that we think that there may be a viable way forward. That's what we're exploring. And I think that that's our job to do in academia. And with that thought, I'd like to thank you for your attention.