Welcome, everyone, to 100 Climate Conversations. Thanks so much for coming along. Today’s number 38 of 100 conversations happening every Friday, and the series presents 100 visionary Australians that are taking positive action to respond to the most critical issue of our time, climate change. We are recording live today from the Boiler Hall of the Powerhouse museum. Before it was a museum, this was the Ultimo Power Station. It supplied coal powered electricity to Sydney’s tram system in the 1960s and we’re now moving forward to the next step, I guess, looking at how we replace that particular approach.

I’d like to acknowledge the Traditional Custodians of the ancestral homelands upon which we make today the Gadigal People of the Eora Nation, and we respect their Elders past, present and future and recognise their continuous connection to Country. I’m Craig Reucassel, you might know me from such documentaries as War on Waste or climate documentaries like Fight for Planet A and Big Weather.

Professor Michael Fuhrer is trying to solve the world’s significant computing carbon emissions. His research focuses on alternatives to silicon computing chips and explores new materials that are just a few atoms thick. Fuhrer leads the Australian Research Council’s Centre of Excellence for Future Low Energy Electronics Technologies at Monash University and founded the Monash Center for Atomically Thin Materials. We are so thrilled to have him join us today, so please join me in welcoming Michael. So, Michael, you grew up in Texas. You have journeyed around America and the world. You did your PhD at Berkeley in physics across the bay from Silicon Valley. You worked for years at the University of Maryland, and you now relocated to Australia. What area of physics has your career been in?

Yeah, so the area of physics that I work in is what we call condensed matter physics. And so, condensed matter means solids and liquids. I’m particularly interested in electronic materials, materials that could be useful for electronics and how materials conduct electricity and things like that. And particularly interested in nanomaterials and materials that are somehow structured on the scale of nanometers or a few atoms.

Now I know that people in physics who are very theoretical in just dealing with the theory, are you more hands on? You’re more kind of, I guess, experimental with your physics?

Yeah, that’s right. I do experimental physics, so we do experiments in the laboratory. I work with a team of students and postdoctoral researchers. We use a number of different techniques. We make new materials, and we study their properties in a variety of ways in the lab.

So, you actually create new materials that have not been made before in a laboratory?

Yeah, exactly. I mean, we are making new materials that haven’t been made, I would say, almost on a daily basis. I mean, not a new material every day, but most of the time we are studying things that only a few labs around the world are studying.

So, you’re the director of the ARC Centre of Excellence for Future Low Energy Electronics Technology, which is FLEET. What’s it kind of looking at?

So, FLEET is trying to reduce the amount of energy that is used in computing devices. So, all of the things that we use for computation, that could be our devices that we have on our desk or in our pocket. And it can be server farms and all of the devices that pass information from one place to another. All of the computing technology that we use, and we want to reduce the energy that’s used in that technology.

So, we’re going to talk soon about the kind of particular approach you’re taking; Is FLEET looking at lots of different ways, like have you kind of got a lot of different experiments look into this?

Yeah, it’s a hard problem. The current technology that we are using to make computer chips is about 40 years old. It works very, very well. We’ve spent an enormous effort developing that technology and making it better and better. And so, coming up with something that’s really radically new is very difficult. And it needs a basic research approach. We don’t know what the winning technology is going to be, and so we do have to try a number of approaches.

Right. So, let’s get into this. Now, in this series, I guess we’ve looked at climate and a lot of issues such as, energy and agriculture and that kind of thing and policy. Now, I must admit that personally, when I kind of look at my computer, I don’t really think of that as being a big part of my carbon footprint. I don’t think of that as being a big part of the problem here. But what kind of scales are we talking about in terms of emissions and energy use when we come to computing?

I think to address the first thing you said, I think one of the things is that we’re not aware of the energy use because a lot of the energy use that’s happening is happening not in the device that’s in our hand or on our desk, although that is some of the energy consumption. But it’s happening out there in the cloud. And so, what we’ve seen in the last couple of decades is this really big move to moving all of the computation that we’re doing off into some server farm somewhere. And those server farms use enormous amounts of energy. So, it’s a big problem. It’s a, well, it’s a big issue, I would say.

Now, computing uses about 10 per cent of the electricity that we use worldwide. I think the bigger issue is that it’s growing rapidly. So, many of the sectors that we look at in terms of energy consumption are flat or maybe even declining. Energy use in computation, the recent estimates that I’ve seen say that it’s really starting to take off and perhaps doubling every three years. So, this is something that is – the energy that is being used in computation is going up rapidly, that’s for sure, and may be going up very rapidly in the next coming decade or so.

That’s fascinating, I guess I think of my computer and my phone and I go, well, I’m charging that off solar it’s fine. But a lot of the – most of the energy that I’m actually using when I’m using those is being used in a server farm somewhere. Talk me through these server farms, because you’re right, we talk about the cloud as if it is actually this, something floating in space, but it’s not. It’s an actual physical place, isn’t it?

I mean, if you think about it, most of the things that you’re doing, you know, you upload a video to Facebook and that takes a while, right? What’s happening is that Facebook has taken that video and then they’re going to process it somehow. They’re going to compress it. They’re going to, you know, downsize it, whatever they’re going to do. And so, it’s a lot of processing that’s going on, but it’s not happening in your phone. It’s happening on a computer somewhere, not on your phone. And that computer is using quite a bit of energy. And it’s the same thing if you stream a video.

You know, Chromebooks are very popular these days and Chromebooks are essentially doing all of the computations somewhere else. They’re not really on your laptop. So, that’s part of it. Desktops actually can use some energy if you’ve got a computer and you’re actually doing something active on it, you’ll hear that fan running. You know, it’s dissipating a few hundred watts of energy. If you’re a gamer, you know that those computers can use a lot of energy. There’s big heatsinks in there, big fans. People have water cooled computers. You know, all of that heat is coming from energy that was used in the in the computations.

So, if I’m sitting there and streaming away, just what’s the kind of carbon footprint of that?

You know, these things are very difficult to estimate because it depends a lot on well, okay, what was the resolution of the video? You know, where did it come from? But, you know, we tried to nail down this figure. There are some pretty credible estimates that, you know, six hours of streaming video is something like burning a litre of petrol. It can be quite significant. The funny thing is these things are getting more efficient every year. So, it’s not that there’s nothing happening in computing, you know, every year you can buy more efficient computers.

But the point is that every year we want much more out of our computers, and so we want to do lots more. And that’s what’s really going to drive these things, is that we want computers to do more in the future. They’re doing a lot now. And every year we want you know, we want self-driving cars. You know, I would love it if my phone would translate somebody’s speech in real time, you know, which they can do passably well now, and they’ll do it better in the future. You know, there’s lots of things that we want computers to do, and those things are going to take energy. We expect more and more and that’s a good thing, actually. You know, computers do a lot of really great things for us. They make a lot of other industries really efficient. It’s much better if I can get on a really high-quality Zoom call with a colleague in the US instead of going there on a plane. So, that’s an energy efficiency, right? That is actually saving energy, but it does cost something. And so, we want to be able to do those things sustainably as well.

I’ve never felt so good about being so behind on my streaming. This is great to hear. But like, are you talking about the fact that each time we do get a computer coming out or a new phone that they are more efficient, so they’re getting more and more efficient. Let’s start with kind of computer 101. What is the current technology we’re using?

So, the current technology is a particular technology that uses silicon. So, we think of computers as made of silicon, that’s correct.

Dug out of the Silicon Valley. That’s how it works, right?

Yeah, exactly. I mean, silicon is a major component of sand. It’s one of the most common elements on earth. There’s lots of silicon around it. We’re not going to run out. But the technology is called silicon CMOS. CMOS is complementary metal oxide semiconductor. It doesn’t really matter what it means, but it’s a way to take basically pieces of silicon, which is a semiconductor and pattern on the surface of that silicon, little tiny electronic switches. And those switches are called transistors and they’re solid devices. So, there are no moving parts, and they switch electricity. And on a computer chip, there are literally now billions of transistors. So, the computer chip in your iPhone has several billion transistors on it.

So, we have – and when I say we, I mean humankind. Humans have made about 10 to the 22 transistors in history, most of them in the last few years because of exponential growth. So, that’s 10,000 billion billion transistors. So, it’s about 1 trillion transistors for every person on earth, something like that. So, it’s more of any object that’s been made by far. It’s more than there are grains of sand on the earth. We made that, right. So, humans are very, very good at making transistors. I think if you – somebody from the far future wanted to define humans, they would call us the transistor making ape, right. We are – that’s what we do. And we use lots of them. They’re very useful, you know, they do just about everything in our everyday lives. So, they’re great.

We have gotten much better every year at making these transistors. The beauty of the process that we use now is that people looked at it and they said, okay, here’s a recipe where every year we know exactly how to make these transistors just a little bit smaller and a little bit faster and a little bit more energy efficient. And so, well, we’re making them this way now, but next year we’re going to make them a little bit smaller and then the next year a little bit smaller again. And they’re going to get more energy efficient. We’ll be able to pack more on the surface of a chip, so more transistors into one computer chip. And we make them cheaper actually. So, the cost per transistor goes down and the energy use goes down. And so, they just get better and better and that’s great. That’s a phenomenon called Moore’s Law. So, Gordon Moore observed what was happening in the computer industry back in the 60s and said demand seems to be growing exponentially. It’s not really a law, it’s just a plan, really.

And that plan has worked really well for more than four decades, but it’s kind of running out of steam. The transistors now are just really, really tiny. It costs, you know, tens of billions of dollars to build the factories that make the state-of-the-art computer chips. There’s only three companies in the world that can do that now. When we started our center, there were four. One of them dropped out, you know, eventually they’ll just be one. So, it’s very, very hard to make these devices and this idea, this Moore’s Law, every year we’re going to make the devices a little bit smaller. They’ve been kind of falling off the trend. So, used to be every two years the devices would get smaller by a factor of – 30 per cent smaller. And now it’s taking three years or four years. And eventually we’re going to run out to the point where, you know, we can’t do them any better. And that means they’re not going to get more energy efficient. But we still want more computing. So, more energy, but the devices aren’t any more efficient.

So, you’re looking at a new alternative to this. This has slightly blown my mind. So, at the moment you said I’ve got a billion transistors in my phone. So, how small is it currently? And then you’re talking about going a next level smaller than that.

So, how small is it currently, the transistors there are – it’s a bit hard to say. So, currently you probably have a transistor in your iPhone if you’ve got the latest model, which is a so-called five nanometer transistor. Now, five nanometers is about 20 atoms or so across. Now the actual transistor –

For those of us that don’t use atoms as our general measuring. I don’t have my atom ruler out. Can you see it?

It’s too small to see. So, certainly the transistors that are on the chip in your iPhone, if you got out a really, really good microscopes you wouldn’t be able to – you still wouldn’t be able to see them. So, they are that small. I should say that making things smaller is part of the problem. So, we’ve gotten to the limit of being able to make things smaller, so we have to make them better. And so, we’re not necessarily trying to make the transistors smaller. We are using materials that are small in a sense, but we are trying to make them switch with lower voltage and therefore lower energy. It’s basically a qualitatively different approach. They will have to be small, but we want to do it different.

So okay, well let’s go back then. So, it’s not just about size, it’s about making it better. Now I think this goes back to material can be classified in two ways like metals that conduct electricity and insulators which don’t. However, there was a Nobel Prize discovery for physics in 2016 that came up with a third approach, which is called Topological Insulators. Now, I gave up physics at the end of year 11, so you’re going to have to talk us through this. What’s a Topological Insulator?

So, this is really quite astounding, right? I mean, seriously, physicists believe there’re really only two kinds of solid materials in the world. There are things that conduct electricity, metals like aluminium or copper. And there are insulators, you know, glass is an insulator. Silicon is actually an insulator. Semiconductors are insulators, but they’re insulators that have a small energy barrier to conduction. But they’re insulators. And it’s just amazing that at some point a couple of physicists sat down and said, well, you know, there’s actually another kind of insulator and it’s a bit complicated. So, it involves a kind of mathematics called topology.

Topology tells us that a ball is the same as a saucer and a donut is the same as a coffee mug. The donut is the same as a coffee mug because a coffee mug has a hole where the handle is. Topology studies the – essentially, it’s a study of shapes. It says, well, you can deform one shape into another, but there’s a kind of mathematical description of that shape that just tells you that it has a hole. And, in fact, there’s a particular mathematical calculation you can do of the curvature of an object. You take the curvature, and you sum up the curvature over the entire object, and it turns out you get an integer, and that integer tells you the number of holes. And so, there are mathematical theorems that in topology that can describe what a shape is. And there’s a kind of a property of the electrons in a material that is topological. And that’s about all I can say.

So, how does that then contribute to this new approach to transferring electricity? Like have they discovered a new type of material? Is that what’s happening?

So, it’s a whole class of materials. And the outcome of having this topology is that these materials are insulating in their interior, but they conduct on their boundaries. And so, if it’s a three-dimensional material, it’s insulating in the inside and then it has surfaces that are conducting. If you make a material very thin and it’s a topological insulator, then its interior area is insulating and then the edges conduct and these edges, it turns out, can conduct perfectly. So, they conduct without resistance. That’s quite exciting. So, resistance is one of the ways that energy is dissipated in electronics. And so, you can have something that has zero resistance that already sounds pretty exciting for making better electronics.

We talked earlier about our computers working hard, and when my kids are gaming, all the heat that is created. Is it the resistance that’s creating that heat? So, if you have no resistance, does that mean you don’t get the heat, you don’t get the wastage of the electricity?

It’s some of it. Actually, it turns out it’s not the biggest part. So, these materials are exciting, not just for the fact that they conduct without resistance. So, ultimately what happens is these transistors work because there’s a little capacitor that you have to charge up and the capacitance gets charged up and then the switch, the transistor opens and then when it’s done, you throw away the energy on that capacitor and it’s not a resistive energy, but there is energy there. And the way to reduce that energy is to reduce the voltage at which the switches operate. And that’s the thing that we’ve discovered about these Topological Insulators is that they can switch at a much lower voltage.

What kind of energy savings are we talking, if you can get this to work?

I mean, we’re hoping that we can get factors of 10 or you know, I mean, it’s possible in principle, I think to get factors of 100 or something like that. And so, given that we can make transistors of a certain size now if we were just to plug in these new topological materials instead of silicon, we think we could reduce the energy by a factor of 10, maybe more.

Which is huge if we’re talking about computing energy being 10 per cent of the world’s electricity use.

It’s a big deal.

That’s a huge difference. You’re trying to find the materials to do this. So, you’re actually what, creating these? Are you making these materials now in a laboratory?

Yeah, we’re back in the lab, the lab’s in Melbourne. But back in the lab we’re looking at a material right now called Tungsten ditelluride. And so, it’s got tungsten and tellurium, two elements. We grow that material in a vacuum chamber, just a few atoms thick, layers of this material. And so, we are, we’re making it and studying it.

I’ve heard this called two dimensional materials. They can’t really be two dimensional, can they, or is that just the scale.

So, that really refers to the behaviour of the electrons in the material. So yes, we can make materials that are just one atom thick or a few atoms thick. So, graphene is a famous example. Graphene is one atom thick carbon. So, graphite has these sheets of carbon that are stacked one on another. They look like chicken wire. They’re hexagonal arrangement, a honeycomb lattice of the carbon atoms. You can peel off one sheet, study that. So, that was just one atom thick carbon. That’s really interesting material. But, you know, one atom has a thickness, so it’s not really two dimensional. There’s nothing really two dimensional in this world. But the idea is that the electrons in the material act as if they can only move in a plane, and so they’re only free to move in this direction or this direction. They can’t move out of the plane. And so, that really changes their properties, the fact that they really just have no way to move in one of the directions.

So, is that what creates the greater efficiency, that they can only go forwards or backwards?

It is in a sense, that’s part of it. Different things happen, the electrons behave differently when they’re confined, and they can only move in two directions.

We talk about nanotechnology. Is this kind of nanotechnology. Is this what you’re dealing with here?

Yeah, it’s nanotechnology in the sense that these materials tend to be less than a nanometre thick, so a nanometre’s a billionth of a metre. And so, it is about the scale of atoms. And again, the idea is that once you start structuring these materials on that scale, then the electrons in those materials start to behave differently.

So, you’re at the point now of kind of experimenting with new materials. You’re trying to find the best example of this. At what stage overall of this project are you at? Like how long till I can expect to see one of your new materials appearing in my computer or my phone or in something that’s, you know, in the real world. Do you have a kind of timeline on that?

I mean, I certainly get asked that a lot. This is at a kind of a basic research stage where we again, we have a concept for how we want to make a transistor, but in many cases, we know that there should be materials that have a certain property, but we have to actually be able to make that material and then prove that it really does have that property. And then we have to be able to put materials together and build the whole transistor. And so, in terms of this topological transistor, it’s a very early stage. So, we’ve been able to demonstrate that, yes, you can switch these materials. They seem to switch at a low voltage. We haven’t really built them into a transistor yet, but we are working towards that.

There’s a kind of a foundation of basic research that is difficult, it’s long and you often go down paths that don’t work out and you have to redirect. But then I think you hit gold and you really get the thing that works well. I think it can take off fairly rapidly. When it becomes an engineering problem, engineering problems are huge, but it becomes a little bit easier to know, you know, how to do the development to kind of bring it from, oh, now we’ve got a working prototype, we can make it into a, you know, really like a working computer.

So, you’re kind of in that stage, the 2016 Nobel Prize for the topological material, that was for theoretical physics. I mean, they just came up with a theory. You’re in this first step of going, how do we take this theory and turn it into reality? And then the next step is how to be turn it into kind of engineering and a product that comes. So, could this be 10 years away or do you not have a sense of the time?

I think yes, 10 years is about the scale that we’re talking. It could be 10 or could be 20 years.

This technology, I mean, we’ve talked about this from the perspective of greater energy efficiency and obviously the kind of climate perspective of reducing energy use in that. Are there other positives? So, if I’m if I’m a phone user or a computer user, is your chip going to have other benefits? Is it going to be more powerful? Is it going to be able to do other things?

So, computing power and energy use are kind of a tradeoff, right? So, there are two sides of the same coin. So, you either get more computing power for the same amount of energy that you’re using, or you can get similar computing power that you have now with much lower energy, right. So, which do you want, do you want your battery to last longer? Do you want to be able to stream more videos or whatever. So, certainly you can do both with a more efficient technology. And that’s what we want. I think the overall message, though, is that computing is great, and we want more of it, right? I mean, we want to be able to do more with computers, but we want to be able to do that sustainably, right. Again, you know, computing reduces the energy that we use in all kinds of other tasks. You know, it makes lots of things more efficient. And so, we would like to be able to do more of that, but we need to be able to do that sustainably.

Michael, what if I said to you, ‘Well look, Michael, all this stuff you’re talking about, you’re talking about 10 years down the track, you’re going to come up with this new thing. Why don’t we just put renewable energy on all the server farms, you know, cut out the carbon footprint of these servers and these computers, problem solved. And, you know, you can have time, you’ve got time to discover this.’ That’s using existing technologies. Is that a solution that is likely?

We have to make the energy generation, the electricity generation that we’re doing now sustainable. But ultimately, there’s going to be a limit to how much energy, how much power we generate worldwide. So, there’s an upper limit to how much computation we can do. At the current rate, computation will use all the energy in the world in the next two decades. So, ultimately, this is a resource. It’s a resource for the good of humanity. We all would like more of that resource. It makes all of our lives richer, and the amount of that resource that we can use sustainably is determined by how energy efficient it is.

Yeah, and I guess this is the thing is that yes, we can use renewable energy, but we also need to become more efficient in everything we’re using as well because as you say, our energy use continues to grow. I mean, I find it fascinating that we’ve managed to come up with cryptocurrencies. You know, you hear this thing constantly that Bitcoin mining uses as much energy as Greece does, that kind of thing. We just seem to continually come up with new ways to use more and more computation, more and more energy. You don’t see that stopping?

Well, I hope the Bitcoin mining stops actually, I’m not sure if I should say that, but –

It’s okay I’m sure the crypto bros won’t come after you.

Yes, it’s very wasteful, right? I mean, I read a report recently that estimated that Bitcoin mining uses – is responsible for more carbon emissions than beef worldwide. You know, so it’s a big issue. I mean, Bitcoin mining is reopening coal fired power plants that closed so they can put these basically these mining server farms, you know, near the power plants. And look it’s a bad example because I think it’s intentionally wasteful, right. I mean, the idea is that Bitcoin mining is intentionally made computationally difficult so that it costs money to do it, resources, somebody’s effort but really ultimately it costs energy, right. And that was a bad plan, you know, so they should’ve done something a little differently there.

But, you know, that’s a wasteful use of computation because it’s – but there are certainly uses of computation that are good. And we want those uses. And so, I do think that we will have lots of really good uses for computation in the future. You know, we’d like to understand global warming. We’d like to understand how the climate is changing. It’s a very complex modelling problem that requires really powerful computers to tackle, and they use energy. Now, that’s unfortunate because that’s the problem we’re trying to solve. But, you know, we would like to spend a little bit of energy doing really important computation so that we can save more energy somewhere else.

What I find fascinating about this particular conversation is that in 2016, this entirely new type of material is discovered in a theoretical sense, that you are currently trying to create new materials every day. I think we sometimes think of ourselves as being, you know, we’re at the forefront of science and we know the answers. But there are still so many answers out there. So, many things that we don’t know the answer to. I mean, you know, how many parts of our scientific knowledge kind of hit a wall and go, we don’t know the answer to this yet?

Look, it’s very exciting to work in science. I love what I do. We’re generating new knowledge and there’s lots of surprises. There are many things that we discover that were unexpected. Every year there’s something really interesting that totally unexpected that comes out of this field. Just it’s quite amazing. I mean, it’s basically a field where, you know, complexity is at the heart of it, right? We deal with systems that have huge numbers of electrons. Those electrons all interact with each other. And they can do things that you couldn’t necessarily predict. And they do exciting new things. And some of them turn out to be very useful.

When I ditched my physics at the end of high school, I thought I was going into the kind of creative fields and choosing the creative subjects. But it’s interesting because I’ve heard you talk about your work and the creativity of your work, how much creativity it takes to kind of do these things. So, I guess talk me through the creativity of science.

Creativity is interesting. I mean, we talk about creativity a lot in science, and I think it’s an important aspect of science and it’s an important aspect of scientists that they think creatively, that they’re open to new ideas. It’s an interesting balance, actually. So, there are some people that they don’t necessarily have that kind of creativity. They’re really fantastic scientists, but they’re, you know, not coming up with new ideas on their own. And then you actually can go too far the other direction. There are some people who will chase every new idea down a rabbit hole. And so, there’s a kind of a balance between creativity and coming up with interesting new ideas and seeing new things that are happening and also kind of figuring out which are the ones that are important. But creativity and being able to think outside the box, open to new ideas is definitely part of science.

Do you find that the best breakthroughs come from just slowly stepping through, or have you sometimes kind of gone, why don’t we try this? You know, just kind of thinking outside of the box?

We definitely have a quite a bit of, oh, why don’t we just try this? It’s funny because I think people learn in grade school that science is about, well, you have a hypothesis, you start with the hypothesis, and then you figure out a way to test the hypothesis. You know, it’s either right or it’s wrong. You go back, you modify your hypothesis, etc. A lot of what we do is actually discovery driven where we don’t actually know what’s going to happen, but we have a hunch that it might be interesting. And there are lots of good things that come out of that.

Graphene, this first two-dimensional material. We had a lot of ideas that it might be interesting. I think probably 2 per cent of the interesting properties of graphene were thought of before somebody actually made it. And one of the interesting things that it led to was this concept of a Topological Insulator, which the theorists only got thinking about because graphene existed. And of course, there’s no reason that they had to wait for graphene to exist to start thinking about that problem, but anyway, that’s the way it happened. So, a lot of it is based on discovery and serendipity and accident. And it’s quite a bit messier than you might think.

Well, I tell you what, Michael, you’ve certainly shown me that I know very little about the computers and phones that I use, and I take so much for granted. It’s extraordinary to see the amount of science, the amount of knowledge that has gone into creating those. And we wish you the best of luck with solving the next problem and creating the next material which will make our phones and our computing more efficient in the future. Please thank Michael Fuhrer. You can follow the program online, you can subscribe wherever you get your podcasts. You can also visit the 100 Climate Conversations exhibition or join us for a live recording like this one. You can go to 100climateconversations.com and just search for 100 Climate Conversations in your pod catcher of choice.

This is a significant new project for the museum and the records of these conversations will form a new climate change archive preserved for future generations in the Powerhouse collection of over 500,000 objects that tell the stories of our time. It is particularly important to First Nations peoples to preserve conversations like this, building on the oral histories and traditions of passing down our knowledges, sciences and innovations which we know allowed our Countries to thrive for tens of thousands of years.