Welcome to zero. I'm Akshatrati this week red photons, blue photons and profiting on sunshine. When you think of the iPhone, there's one person that comes to mind, Steve Jobs. Same with electric vehicles. Elon Musk looms large, even though the industry now extends well beyond him. But what if I asked you about the solar panel? Does anyone come to mind? Probably not, even though it's one of the most revolutionary
pieces of technology. We have to reduce emissions. So I'm going to offer up a candidate, Professor Martin Green, who has been called the godfather of solar.
We held the world record facilic and sell performance for three of the last four decades. The two main competitive technologies, which last year count of an ninety percent of the world's production, originated in air laboratory in the nineteen nineties.
Martin Green is a professor at the University of New South Wales in Sydney and the director of the Australian Center for Advanced photovold Takes. And I want to emphasize something he just said, because it's wild. Ninety percent of the solar panels produced last year were based on the inventions that came out of Hayes Lab. Martin made his first solar panel in nineteen seventy one, more than fifty
years ago. The industry at that point, if you would call it, that, was tiny, but it got a boost in the aftermath of the nineteen seventy three OPEC oil crisis as the US and other countries sought to reduce their reliance on imported oil.
Oh it scranger around for research fund theater research program going there that provide additional funding for academics like me, So you know, the timing was pretty good.
With the money, Martin funded a scrappy operation. He combed through warehouses in the US and shipped secondhand equipment from the microelectronics industry back to Australia. There he and his team would assemble the equipment to make the test panels and it worked. By the late nineteen seventies, he was out competing scientists at NASA to create better and better solar cells, the same NASA that had just put a man on the moon.
We were able to cream all these NASA subcontract His little Tin Park group in Australia got some international attention, which helped us with fundraising and we got a first world record in eighty three, so that was an eighteen percent efficient cell.
Efficiency is an important concept in solar but simply it's a measure of how much energy from the sun that hits a panel is converted into usable electricity. The higher the efficiency, the more electricity the panel produces from the same amount of sunlight. And this matters because the more electricity a panel prity uses, the quicker it pays for itself, and the cheaper it becomes relative to other forms of
electricity generation. While an eighteen percent efficient cell doesn't sound all that much, it was a milestone achievement at the time, and then year after year, Martin's team beat their own record, holding it for all but six months between nineteen eighty three and twenty fourteen. This is the first reason that Martin is referred to as the Godfather of solar. The second is his link to China.
One of my students, in particular, doctor Jenrong. She was fired with this ambition of establishing manufacturing in China, and we knew how difficult it be, so I personally tried to dissuade him. Just luckily I didn't because we wouldn't have the modern industry without his determination to go ahead.
Martin is responsible for training hundreds of Chinese engineers who have gone on to build the vast solar manufacturing capacity that China now has. That includes the one he just mentioned, Shur jug Rong, who founded Suntech and became the world's first solar billionaire when his company floated on the New York Stock Exchange in two thousand and five. What Martin's team has proved in the lab his students have gone
on to build and sell around the world. His inventions and his lab underpin this vital technology for decarbonization, and he is still going strong. So on my visit to Australia this summer, I had to sit down with him to hear his story firsthand, the crucial role he has played in commercializing solar and his predictions for the industry's future. Professor Green, welcome to the show.
Oh, thank you very much, pleasure to be here.
You are often referred to as the godfather of solar and you madea first solar cell in nineteen seventy one. Did you go in realizing what kind of impact solar could have on the world back then?
Probably not really, like I think it's only become clear over the last five years, perhaps just the huge impact that solo is going to have in that it's our best weapon we have in fighting climate change. So we certainly didn't think that would be the case in nineteen seventy one. We thought it might do something useful, but it wasn't expecting it would be the key.
A lot of the inventions that power of the solar industry have come from here in Australia, through the University of New South Wales, through your work. What is it that made Australia such a hub for advances in solar at such a large scale?
Yeah, no, I guess we held the world record facilic and cell performance for three of the last four decades, so you know, from the early nineteen eighties through until quite recently, when you're out in front and you've got a critical mass of good people in your team, it's easy to stay out in front, I think. And we kept working on new ideas and some of them paid off.
So the two main competitive technologies, both what's now known as top con and PERK, which last year count of a ninety percent of the world's production, originated in our laboratory in the nineteen eighties, so we suggested and first demonstrate both of those technologies, but the PERK was the one that was first to make commercial impact.
A solar panel is made up of multiple cells. The exact number varies, but it's these cells where the magic happens and where Martin's team has made huge improvements to increase the panel's efficiency. Martin mentioned PERK, which stands for passivated emitur and rear contact. It's a type of cell that was first developed in Martin's lab in the early nineteen eighties and set a new world record for solar
cell efficiency in nineteen eighty nine. Very simply put, PERK cells work by adding a reflective layer on the back surface of the cell, which bounces light back into the cell so that more of those photons can be converted into electricity. Despite the technology being nearly forty years old, it didn't become widely available until the mid twenty tens. Since then, it's taken the world by storm, but its supremacy is already being challenged by another of Martin's inventions.
Top con TOPCN stands for tunnel oxide passivated contact, and it has the potential to be even more efficient than PERK. The tiny tweak it makes to gain that extra efficiency is too complicated to explain, even more complicated than the name. Until recently, top CON cells have been more expensive to make than PERK, but advances in manufacturing mean that in twenty twenty four, top CON production is due to overtake PERK, according to analysis by Bloomberg NAF so.
There's now more PERK modules installed worldwide than all the solar electricity generation in the history of the human race. Is one way I like to look at it. So we're very proud of that, obviously, but it looks like the next one is going to be top CON, which also originates in our lab. We gave priority to BURK because it was so simpler technology to manufacture and got us to our twenty five percent efficiency target that we set back in the eighties and realized in the nineteen
nineties in our group. So both of those technologies are kind to play a big role within the industry over the rest of this decade, and.
A lot of the inventions made in the solar cell in your lab in the nineteen seventeen and eighties didn't really become commercial until the twenty tenths. Why was that.
Yeah, there's a number of reasons. One was the industry was not really existent, you know, before the twenty first century. Back in the twentieth century, it was I used to describe it as a boutique industry. So the companies that were involved were a lot of them were the oil companies, solar companies, you know, part of their public relations activities.
It wasn't really until the present century that the industry got really competitive and switched from being a bow tiki industry to a very competitive industry where every possible advantage was key the success of the companies involved.
Now very few people know. And the reason why the godfather title is given to you is that many of the students that you trained are the very people who are now running big Chinese solar companies or powering the technology that big Chinese solar companies are deploying today in the market. And China is nearly half the world production of solar panels today. So how did that come about?
So, you know, as I said, I guess in the twentieth century boutique industry, and it was really my students who got interested in manufacturing in China at the turn of the century that really created the modern industry and made solo selles a reality in terms of being competitive
in costs and production volumes and so on. But one of my students, in particular, doctor Jenrong, she he was fired with this ambition of establishing manufacturing in China, and we knew how difficult it be, so I personally tried to dissuade him. Luckily I didn't because we wouldn't have the modern industry without his determination to go ahead.
Scherzanrong's new venture was Suntech, founded in two thousand and one as the first mass market solar manufacturer in China. While there had been a handful of small scale solar producers in China up to that point, Sure leveraged his experience at Green's lab to make punnels that were both more efficient and cheaper. He blew his competition out of the water, and for several years was the world's largest solar manufacturer.
His progress was noted by US investment banks, you know, the big ones like Goldman, Sachs and Morgan Stanley, with the two that I'm aware of that got interested in getting him to list on the US exchanges. Because Chinese stocks were very popular in that era and everyone could see it going very well, which it did do, and Changroong listed in two thousand and five, only three years
after his first production of the sales. He listed on the New York Stock Exchange, but it was the biggest technology flow of two thousand and five, so huge success. And Changmong had started his activities with six million US dollars raised from local companies, and all of a suddenly he got four hundred million US injected into the company through this capital raising, and he still owned most of the company, so he became the first solar billionaire through
that listing. But that was really important because it created an avalanche of US investment banks looking for other Chinese companies they could pass off as a clone of that perst successful company. And it also, of course the plenty of Chinese companies interested in getting a wind for cash
injection of four hundred million. So between two thousand and five and twenty ten, there were ten Chinese solar companies that listed on the US exchanges New York and Nasdek, and six of those ten are in the still in the top ten manufacturers twenty years after that period, so it helped form the backbone of the industry.
Suntech reached a peak valuation of sixteen billion dollars, but by late twenty thirteen, the New York Stock Exchange delisted the company after it racked up billions of dollars a debt while facing stiff competition from other Chinese solar manufacturers. Shure Jianrong was made to step down as chairman and
the company declared bankruptcy in early twenty fourteen. If you'd like to know more about this turbulent period and Solar's boom and bus cycles, please listen to our conversation with Bloomberg and EF Solar analyst Jenny Chase that's linked in the show notes. Now, you mentioned shir Jongrong who created Suntach Power, but you trained a number of other students in the University of New South Wales.
Yeah, so, chingong success prompted other Chinese based companies to want to get into listing on the USA exchanges, and part of the due diligence of the US investment banks was making sure they had contact to good technology. So because Genrong had come from our group, cruiting people from our group became a priority to take a leading technical role in the company, so we lost a lot of our staff over that period. But it turned out to
be really important because you know two things. It's lowered the cost of solar enormously so that you can now talk about it as a viable option in climate change mitigation. It also created a huge industry in China, and China is installing, you know, forty percent of the world's solar now, and that's the country where you already want sold to get installed. Otherwise they would be installing more coal plant, which is the last thing you want China to be doing.
So both those reasons, you know, we can feel proud that we were able to kick start the industry in that way.
So scientific inventions of these kinds can be hugely profitable. There are obviously places where many times entrepreneurs from universities benefit from them. Did you ever consider moving from academia to business given the kinds of returns you could have got.
I've started a few spin off companies, but I've enjoyed my career in academia because it's been so rewarding, so I was never tempted to give up my full time job to take on a company activity, although I have acted as research directors and so on of different companies that have spun off from our group. So I've been involved with the industry, but I've never been tempted to throw my hat into the ring and become a full time industrial participant.
China's role in the world has also drastically changed over the past three decades as its economy has grown so much, things have soured a little bit less spit it that way. How have you seen that period, especially when you had Chinese students come over and then you train them, they go back to China and then build this manufacturing capacity which other countries now see as a threat because they want solar panels, but they don't want to depend on China.
How have you seen that play out as students have come to the university to train on solar technology here in Australia.
Yeah, so Australian universities are quite depended on Chinese overseas students because that make up a huge fraction of their total budget. So we don't want them to stop coming. But there is a chance in the present more aggressive Chinese international stance that something like that will happen. But you know, the other thing we did was at the turn of this century, we created the world's first undergraduate degree program in photovoltaic engineering, and about half of our
students are overseas students from China. But I think it's been a good outcome from the world in that it's given us the cheap solar cells, and now other countries have the chance to get into solar cell manufactur I don't think they'll ever be able to match the costs in China, but the costs have come down so low that I don't think you need to have the absolute lowest cost to be competitive with the other options that
are available. So I'm working with a company in India, for example, to try and get them up to manufacturing, and I think India has the best prospects of establishing a viable industry because they, like China, really need the cells and they're quite determined to make a success of getting into cell manufacturing.
Well, that's an interesting way of putting it, because you're saying for solar to continue to be a viable industry, you don't actually need the cheapest sell. You just need to be able to make it effectively in places that have a demand for it.
Yes, I think that's right, because I think the cells have overshot in terms of the prices that are required
to be competitive with what else is out there. You know, the International Energy Agency a couple of years ago said LA provides the lowest cost electricity in history in some cases, and you know the cells are only going to get cheaper that you know that overshooting might have been required just to convince you know, the more conservative parts of the energy industry that you know, the time it come to make a switch.
After the break. Is Martin's work in the lab solar's final frontier or is it destined for space? You hang out with a lot of people who are in the solar industry and you know, people in government surely, having seen the kind of work that has led to commercial success outside of Australia, there must be feeling within Australia that they probably lost out on something, something that was invented here that they could have commercially benefited from.
Well, you know, the way that the technology did get distributed was through joint ventures with China, So Australia and Chinese joint ventures. So that's the normal way the new inventions are brought to market. The invetors set up a company and then someone buys them out and the invetors cash in on their invention. A lot of my former students are a lot richer than I am as a result of being brought out of joint ventures in China
that like. I think the particular circumstances that have got us to where we are with sol are the very low costs and very active competitive industry results from how students wanted to set up in China. So I think in Australia you just wouldn't have grown to the same size and volume and everything. So I think, you know, a bit of a pipe dream to think that Australia could have done something in the same part as China
has done. There wouldn't have been the same interest from US investors in investing in Australia as they was in China because it was the size of the Chinese market that was encouraging that in investment, and the Australian market is very small by comparison.
We had one of our Bloomoginia analysts, Jenny Cheese.
I don't know if Jenny well so.
Jenny says that solar manufacturing is very bad business because the technology is changing so rapidly that even before you make the money on the equipment you have invested in to build a particular type of solar cell, the technology has changed and you have to bring a new equipment and obviously make new investments. Why is it that the Chinese are able to be profitable in such a fast paced technology environment.
Well, it's all our team's fault in that my students set up the industry in China and they just got to a scale that wasn't matched anywhere in the world. And then everything they could do in China lowered the cost Some of my students used to use a figure of three. If they could buy a piece of equipment from China, it was going to be a third the costs if they bought it from Europe or the USA. And now they're doing everything in China. There's a lot
of movement of people between different companies. They get head hundred if they're doing well, so they might only stay eighteen months at one company then move on to the next. That's quite typical. And then all the equipment suppliers are in China and they're only too willing to spill the beans on how well their company's competitor is doing with their equipment and how they're doing it. And the other thing is a lot of the Chinese industry are on
we chat. There's five hundred of our lumni have their own we Chat group, so they know they're talking about how well a company's doing and things like that. So the information passes around in a way that difficult to see it happening to the same extent in other countries, and that brings everyone up to best practice very quickly and pushes the whole industry on.
You're still active in research. What keeps you going.
Ain thing is we haven't done the job yet. As an academic, you want to push things to the limit. So that's what we did with silicon cells. We thought we'd push the limit. We twenty five percent, which we got to in ninety ninety nine, was you know, about
as far as you could practically go. But you know, now I'm just doing a paper and suggesting that twenty eight percent is where the industry can get to, and twenty nine and a half is the absolute limit for a silicon cell, So you know, twenty eight percent would be probably as far as you can go, although another ten years I might be revising that figure upwards. But single cell, like a a solar cell sort of like a photon converter. You know, a photon with enough energy
will create one electron in the external circuit. It doesn't matter if it's a blue photon or a red photon, they still do the same job.
Photons, the little packets of light that hit solar panels and are converted into electricity, have different energy levels. Blue photons are full of energy, so much so that they can give you some Red photons have less energy. Silicon cells are very good at capturing red photons, but not so good at catching blue ones. That means a lot of potential electricity is not being produced. Martinsteam has made cells of different materials that are much better at capturing
the blue photons. By stacking these cells on top of each other into what's known as a tandem cell, you can catch both types of photons and create a much more efficient solar panel.
If you can stack a cell that's good at handling the blue photons on top of a silicon cell, you can get an improvement in performance. You basically sort of specializing the cell function so you have a cell that can really handle the blue wells stacked on top of a silicon cell. It'll grab all the blue photons and convert them more efficiently than a silicon cell can. And then the red ones who go through to the silicon
which can convert them quite efficiently. So overall you get an efficiency boost from that process.
And this is called the tandem cell. One after the other, and you've built the world record TENEM cell.
Yeah, so we have a tandem converter actual vaball take system that you stick out in the sunlight rather than just testing indoors under flashlights or something. But it converts forty point six percent of the sunlight falling onto the aperture into electricity. So that's presently the world record for real outdoor solar conversion by any technique. And that has four cells converting different parts of the solar spectrum.
And is there a theoretical limit to that type of cell where you mix different technologies.
Yeah, under terrestrial sunlight, it's sixty eight percent is the theoretical limit. So I don't think we'll get anywhere close to that. That requires probably you know, twenty or thirty cells stacked on top of one another, but going up to six cells in a stack. You get an efficiency improvement each time. And you know, the forty percent that we're demonstrated, I think is quite realistic type of figure
to achieve in commerce production. It's not going to happen soon, but maybe twenty years down the track we'll have that type of efficiency in our commercial panels.
And you describe that as terrestrial sunlight, which means sunlight that is coming to the surface after being filtered through the atmosphere. You suggesting that we could have solar in space that could be even higher efficiency.
Yeah, it probably not higher efficiency because the spectrum is slightly different in space because of the filtering that occurs going through the atmosphere. But you've got more energy in space and it's all coming from the same direction. So there's some advantages of converting in space if you can get the energy back here on Earth, you know, efficiently and effectively. The other thing you can do in space is get electricity sort of virtually around the clock, you know,
close to twenty four hours per day. So that's the other advantage of going to space. And you know, there's a reawakening of interest over recent years in that role. But you know, I think terrestrial soil is going to be cheap, and you know, there's probably no real need to go that direction, but yeah, there might be some applications where that proves an effective way of generating electricity.
Solar panels in space sound like a bonker's idea, but it's got some serious minds behind it. In April, the European Space Agency commissioned two concept studies for space based solar panels as part of its Solarist project, with the results due by the end of the year. This is not the only breakthrough being pursued in solar so far. Most of the episode has focused on solar panels made from silicon, but there are a number of other materials
being explored for making even more efficient solar cells. There's a huge bus currently around one technology, in particular, a type of solar cell known as a perovskite, named after the cell's molecular structure. In recent years, it has made the most rapid advancements in terms of efficiency. These cells
are made from lead based compounds, raising questions aboutxicity. However, if they can be commercialized at scale, they have the potential to reach even higher efficiencies than silicon based cells. I wanted to know from Martin what he thought about perovskites and whether they are likely to take silicon's crown.
Yeah, yes, I've been quite interested in that question. You're going back to the eighties, I guess. But silicon has four attributes that's very difficult to match in other materials. You know, one is an abundancy, you know, it's the second most abundant element, neoscruss, and the other is toxicity, it's non toxic. The third one is it makes very
stable material. And fourthly, you can get good efficiency. There's only seven materials in total that have demonstrated over twenty percent efficiency in converting sunlight, and silicon is by far the most stable of those and is the only one
that takes all those for criteria that I mentioned. So there are other materials that have gone into production for solar like catiam Tellier is one, which is a compound of cadmium, which is a highly toxic, very nasty metal, and tullurium, which is very scarce material, like it's even scarcer than gold. It's just that no one's really had a use for it in the past. You know that there's no problem with supply at the present, you can see the problem with that technology. It wouldn't be able
to supply even the present world production of solar. So we've been trying to find materials that tick all those four boxes. The most promising candidate at the moment is perovskite material, but unfortunately it involves lead, which doesn't get a clean bill of health on the toxicity front. It can give you the good efficiency, so you got very big tick in that area, but the stability is the main problem. The outdoor environment is really tough and even
silicon has trouble coping with it in some situations. So a material that is at the opposite end of the spectrum in terms of stability, it's very hard for me to see. Progress has been made, but it's been more linear progress, whereas exponential progress. Instability is required for a viable products. So we're still looking for other candidates because you know, a lot of people are interested in propscites
and working on it. You have many more than working on silicon, I would guess, but I'm not sure that that fundamental difficulty will be overcome in time for it to have an impact. Hopefully these tandem stack cells will come online, you know, sometime around the end of this decade.
We hold the world record at forty point six percent with a lab type process so prohibitively expensive to go into manufacturing with that approach, that what we're hoping is we can repeat that feat of making a forty percent efficient module with technology that slow cost and can be commercialized.
Well, you've been on the top of the game for the past few decades, and I wish you good luck to be on the top of the game for the next few decades. Thank you for coming on the show.
Well, thank you very much. It's been talking to you.
The inventions Martin and his lab have made and his students deployed in the Chinese solar industry have made modern solar possible. It is rare to have one mind contribute so significantly to a world changing technology. Thanks so much for listening to Zero. If you liked this episode, please take a moment to rate and review it, subscribe on Apple Podcasts or Spotify, Send it to a friend or to the most efficient person you know. Get in touch at zero Power at Bloomberg dot Net. Zero's producer is
Oscarboid and senior producer is Christine driscoll. Our theme music is composed by wonderly special thanks this week to David Stringer, Jenny Chase, and Kira bindram i'm Akshatrati back next week