248: Big Perovskite Solar Panel Advances - Dr. Chris Case Interview

https://youtu.be/gbRn1j39M0E

Matt had the chance to chat with Dr. Chris Case, CTO of Oxford PV, about the future of solar energy and their breakthrough perovskite tandem cells. With decades of experience in photovoltaics, Chris shared how this cutting-edge technology is pushing solar panels to unprecedented efficiency levels, all while keeping sustainability and scalability at the forefront.

Watch the Undecided with Matt Ferrell episode, How Record Breaking Perovskites Are Here NOW https://youtu.be/vEgkTnkNhRs?list=PLnTSM-ORSgi7uzySCXq8VXhodHB5B5OiQ

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Matt Ferrell

Host of Undecided with Matt Ferrell, Still TBD, and Trek in Time podcasts

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Sean Ferrell

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What is Still To Be Determined?

Join Matt Ferrell from the YouTube Channel, Undecided, and his brother Sean Ferrell as they discuss electric vehicles, renewable energy, smart technologies, and how they impact our lives. Still TBD continues the conversation from the Undecided YouTube channel.

Hey everybody, today on Still to be Determined, we're talking about Perovskite solar energy research. Well, we aren't, at least I'm not, but some people are, and that'll be exciting for everybody. Hey everybody. I'm Sean Ferrell. I'm a writer. I wrote some sci fi, I wrote some stuff for kids, and I'm just generally curious about technology.

And luckily for me, my brother is that mad. of Undecided with Matt Ferrell, which takes a look at emerging tech and its impact on our lives. And Matt, how are you today? I'm doing well.

I think I've mentioned this before, but by the time people are seeing this, uh, I've had COVID for three weeks.

I'm finally getting over it. The first time I've had it, and it was like, it was making up for lost time. It's been a fun ride.

It's been so long that you've had COVID that when this call started and Matt was like, good news, I tested negative. My first thought was for what? Oh, right. I forgot that you could test negative for that.

That's right. So as I mentioned at the start, perovskite solar energy research is on the table today and this is nothing new for the channel. Perovskite has come up many times before. Matt has been talking about it and the various research that's gone on in that field. And Matt recently had a chance to talk with Dr. Chris Case, the CTO of Oxford PV. Which is a team that is looking at perovskite tandem cells, and they've recently had a breakthrough. And after decades of research, Chris has recently shared how this cutting edge technology is changing solar panels and increasing efficiency levels. And Matt, we've always talked about efficiency isn't the only metric, but of course it is a big one.

So, on now to Matt's conversation with Dr. Chris Case.

Chris, thank you for joining me today to kind of kickstart our conversation around perovskites, tandem cells, what Oxford PV is doing. Before we get into all that, I want to learn a little bit more about you. Could you kind of like tell me what your career path was like, how you ultimately ended up at Oxford PV?

Uh, sure. Uh, and by the way, I've been involved in PV even from the beginning of my career. So, my PhD is in thin film solar cells. So I started in solar. A lot of people who are in solar today are transplants frequently from the semiconductor industry, but I'm actually a pure, you know, pure play solar person.

Uh, but that, and that background was for thin film copper indium selenide or the things that today are called CIGS, those materials. And it's so old and so long ago, all the patents I had have expired. So it just shows you that challenge around bringing technologies to, you know, to commercialization.

Often they take decades. And if you go to the history of solar cells, all the modern and new concepts like PERC and back contact and heterojunction, they date to the eighties and nineties, even the seventies in some cases. And so Perovskite is a little bit different, but I also spent time at a university doing engineering.

This was in material science and also doing solar. And then I had a stint at AT& T Bell Agritouries. And if you think about it, kind of a fun place to have worked because besides being, you know, a place where the transistor was invented, it was also the place where the solar cell, silicon solar cell came from, so a nice place to have been, but, you know, different things.

And then I, uh, sort of transitioned to some industrial companies, uh, did again, uh, factories in, in plant design and chemistry and materials, but ended up, uh, moving to the UK about 25 years ago. So I'm a, a UK resident, a UK citizen, and I've been working here for, for quite a while. And I just, uh, about 10 years ago, received a call, hey, You know, we know you had a solar background.

Can you come help us? This was Oxford PV commercialize their technology, which was a fascinating decision.

What drew you to, like you mentioned, you've been studying solar cells for ever. What drew you to that? Like I'm sure

like you have the same sort of background as a kid and you just like certain things.

And I like a number of things, but they included optics. So, uh, you know, I was building telescopes and mirrors and things like that. I was absolutely fascinated with wireless and remote things. So communications by, you know, uh, by radio. And so the concept of communicating things over the air and that's your transmitting electrical signals of the air.

It's in what you're transmitting light through the air and photons, all those things. So, all I ever did as a kid was build stuff and power it with little bits of solar cells and making gadgets and trying to, you know, make things from radio control planes to little miniature robots and stuff like that.

So I've been doing that really since I was a kid. So combining, you know, photons and electrons together, which of course conceptually is all a solar cell does, it's the simplest. Electrical device. It's a p n junction, right? It's the simplest device. Sometimes it can contrast it, you know, when people say, Oh, is it like, like a chip, like electronics in your red circuits?

Well, chips today have a hundred billion transistors, right? Made in factories that cost 10 billion with a thousand processed steps. We've got something which is effectively half a transistor, but sorry to make a startling different kind of comparison, but it tells you a little bit about the challenges you face, because it's a very different kind of product you have to make.

And you know, the solar cells I used when I built my first house, I paid I think 200 times more for them 30 something years ago than they cost today. They were definitely not economically, uh, smart things, but I wanted to have something cool. Yeah.

Have a power plant on your roof.

Well, well, you know, the Oxford PV Company originally was not doing this.

It was doing BIPV. It was going to make, Oh, wow. Yes. No, the company didn't start with, first of all, didn't start with perovskites, but it started as doing organic solar cells. To make semi transparent building glass that could generate power. So the, you know, I had this concept, vertical power plants.

Imagining the Shard, the biggest building in London, becoming a vertical multi megawatt power plant. You know, it was a great story. It's still a great story, converting buildings into power generation. But it really is a difficult task. Anyway, we, we change paths and to work on this.

Transitioning into perovskites, uh, for those that are less familiar with it, could you kind of walk through like why there is so much interest in perovskites compared to what we're typically using in solar cells?

Well, you know, first of all, to understand that perovskite is the name of a sort of family of compounds, uh, in particular that have a sort of a similar, uh, crystal structure. So it's the perovskite crystal structure and this came, uh, from a mineral that was identified in, discovered in 1839. Name is named after some Russian mineral up mineralogist, and it was called perovskite.

That mineral was calcium titanate, calcium, titanium, and oxygen. But the organization of those atoms, the calcium, titanium, oxygen in a particular organization is the perovskite crystal structure. But just like everything that we understand today about materials, it's the interaction of different atoms and their orientation in crystal structures. I always like to remind people, you know, salt and diamond, the same crystal structure. But boy, are they different materials, right? Very. Just as, you know, graphite and diamond have different things, but they have the same material. So the orientation of those atoms is quite unique.

In the case of the perovskites, in the case of the perovskite for solar, there is no calcium or titanium or oxygen. In the perovskite chemical that's used in the perovskite solar absorber, there are different atoms that were combined, yet they uniquely do something that makes them very good as a solar absorber.

And you know, today, most people, if they think about solar in detail or solar photovoltaics, you know, things that generate electricity, they think of silicon and silicon, very abundant material in the Earth's crust, I think is the second most abundant element of the Earth's crust in the form of sand, right?

Silicon is actually a really poor solar cell. Now you probably are shocked that I'm making that statement, right? Because it is the solar material for 95 percent of the solar cells and solar panels of the world. But it, you know, when it emerged in the, in the fifties, in fact, actually the development of the silicon solar cell came from Bell Laboratories work in the thirties.

When they were looking for replacements for the, for the vacuum tube and they sort of discovered silicon was pretty good and they set it aside during World War II because, you know, they had to focus on, on the war effort and radar at the time. But they actually had that silicon solar cell back in the late thirties.

And then after the war ended, World War II, they went back to work on it and they were trying to find a material that was good at converting electricity, right? So they could power telephone systems in the jungle where batteries constantly fail because of high humidity conditions. But if you look at silicon by itself.

It isn't a very good solar cell material because it's an indirect bandgap semiconductor. So part of the energy that's converted from photons and electrons is wasted sort of in the lattice of the silicon. And its absorption coefficient isn't very good, so it takes quite a chunk of silicon, a good, good thickness to absorb the photons.

And unfortunately, its peak absorption edge is in the red part of the solar spectrum, Which is although a lot of photons come from that in the Sun. They're the weaker part of the spectrum. I mean, everybody probably remembers that when you go out to the beach and you get suntan or sunburn, it doesn't come from the stuff that's keeping you warm, it comes from those photons in the UV part of the solar spectrum, the higher energy.

So silicon has all these poor characteristics, and guess what? Perovskite doesn't. Perovskite actually, and sorry, I was getting eventually getting to the answer to your question. First of all, it's a multi component material. So by having multiple components, you can adjust the ratio of the different atoms in this composition.

So you can change characteristics of the material. Uh, so in the case of silicon, it's got one atom. It can't change its characteristics. It is what it is. Bandgap is what it is. It's absorption coefficient is what it is. In gallium arsenide, it's a binary component. There's two things, and you still can't change anything.

That's its compound. But when you get to three and four and five elements, you can change things, and one of the things you can change is, for example, its bandgap. So in fact, one of the things that's done with perovskites is you adjust the band cap, so where it absorbs best in the solar spectrum to that part which is closer to the blue range and part of the spectrum where the photons are actually in higher energy.

So and in fact other characteristics of the perovskite is it's a direct band cap semiconductor so intrinsically it doesn't waste energy in the conversion of the photons like silicon does. And then the final thing is pretty inexpensive. The raw materials that go into it are actually cheap. And beyond that, and this is something people don't recognize, another disadvantage of silicon, although it is very abundant and intrinsically inexpensive because of its abundance, it is expensive in the form that it needs to be used, which is high purity.

So you spend a lot of energy and a lot of chemicals and a lot of heat. Purifying the silicon because unless it's purified to like one part in a billion or even a trillion, those impurities act as places where the photons after they generate their carriers recombine. So unfortunately, silicon needs to be ultra pure.

Perovskite doesn't. It actually can be utilized in multicrystalline, polycrystalline, thin film, obviously, form without being ultra pure. So the raw materials are available, they're relatively inexpensive, and you don't have to pay for all that high temperature purification. So the payback in energy to produce them as a material is much shorter.

So from a sustainability standpoint, this is really, it's almost the ideal solar cell. And I'd say the ideal solar cell is gallium arsenide. It's got the perfect band gap. It's matched to the peak of the solar spectrum. And gallium arsenide would be the ideal solar cell material except for, well, gallium is relatively scarce.

You could not produce terawatts of that material. Arsenic, well Probably you don't want to use more arsenic than we already use in the world today. And of course, you know, the fabrication is very expensive. So other than that, it would be ideal. So to me, this is like poor person's gallium arsenide. It performs like gallium arsenide, From absorption from a pretty good band gap and from, uh, working in a thin film, but it does so much more.

Yeah. So the perovskites, I mean, it's kind of the Holy grail for solar technology because we can tune it to what we need to do. But one of the big things that, you know, in all the research we've done on this, it's like, It's very prone to short lifespans because it doesn't react well to a lot of stuff that solar panels are going to be subjected to.

So one of the questions I have for you is like, how, how is that not cracked where you can give it a much longer longevity? And get all this benefit of the perovskites you just described.

Well, first of all, let's, let's admit, and I will absolutely admit that the pedigree for perovskite historically and the stories around it were not about its inability to achieve high efficiency.

That you sort of get that for free, but it was questions about durability, et cetera. And it's very, Moisture sensitive, the composition chemicals that go into it tend to be either hygroscopic or sensitive to moisture. And when they react with moisture or exposed to moisture, their degradation products, of course, not only reduce the performance of the solar cell, actually create some things you probably don't want, like a Schneider.

But fundamentally, it is that sensitivity to moisture that can be controlled. I mean, if you think about it, you don't take ordinary solar cells and put them out into the environment. You protect them. And the generic way to protect solar cells is behind glass. And of course, that's both for mechanical protection, but also is for the protection of the solar cell itself.

So effectively, what you have to do with the perovskite is also protect it. But fortunately, you can protect it using Variations of the same approaches you'd use for silicon solar panels, which is encapsulated behind glass. In our case, we've chosen glass at the front and glass at the back. And I have to tell you, glass is pretty good stuff.

I mean, it's virtually impervious, you know, to diffusion. You can diffuse, stuff does diffuse through glass, lots of science fiction stories about you know, things, slow glass, things going through the glass over millennia, but, but it's, it's very impervious, those things. So it's a good capsule for solar cells.

Now that doesn't tell you enough of the story because it's also important that you choose the right chemical constituents for the composition. And you do things that are traditionally important to stabilize solar cells, including silicon because it's defects. Defects in the silicon, which cause its degradation, it's also defects and imperfections in the perovskite.

They're more, they're less prone to those defects, but they still have defects. So managing what happens at interfaces. So between the layers of a solar cell and at the grain boundaries. So the things where, you know, stuff can diffuse between the things is important. And we've spent certainly the bulk of our R& D on perfecting and improving reliability and reducing degradation.

And the approach was not mysterious because. We found that some of our devices, eight years ago, lasted tens of thousands of hours under high stress conditions, but not all of the devices. So that told us something important. It can be made to work, but we had to figure out why it wasn't working. You know, what was it didn't work, and if we could sort of master that or stop that, then we could probably figure out a do it.

So, again, you know, when you have a complicated problem, which is multi components, multi chemicals, and multiple layers of materials, and, you know, things from the raw chemicals all the way through the device, and all the way through to the package device, a lot of stuff, and then you throw into that mix variable temperature and variable light, that's because remember, panels expose during the day to light, and at night they're not, and during the day they get hot, and at night they cool.

That's a complicated problem. Ripe for machine learning approaches. So, we identified the key sort of degradation and defects at each of the places, just the key ones. Not all. That's for the research people to identify the rest and they can do that for the next 50 years if they want. We care about the key ones.

So we can come up with a product that's good enough for the market. And that's what we've done. So, we do have things that we do to control uh, stuff at the interfaces and to passivate those grain boundaries and of course to make a package very effectively sealed against the environment. So not perfect, but good enough.

Yeah, that leads right into the, the actual product that, uh, Oxford PV has released on the market now, which is a tandem perovskite silicon solar cell, which there's benefits to tandem, which I want to talk about. But one of the questions I have is why wouldn't. Is the ultimate goal to get to a pure perovskite cell or do you think that these tandem cells are the future because of how we can tune them to work together?

Well, first of all, it's a great question. And initially when we looked at this, really initially meant when perovskite came into the company before we started the tandem, uh, and I joined the company at the beginning of this journey on, on the multi junction solar cell, people just looked at perovskite as a replacement for silicon.

Okay. Because of all the reasons I described earlier, it's characteristics, it's cost profile, it's sustainability, and the fact is direct band gap, it's just a better solar cell if you can make it stable. So you could make it efficient, you could make it cheap, could you make it stable, in which case you should replace silicon.

But you know what? It's not so easy to displace an incumbent. That's the first problem that has now, look at all the airlines that say, I'm going to come in with a low cost competition for some market that's owned by in one of the major carriers. Six months later, they're out of business because the big carriers simply match the prices and sit there and they don't care.

So how are you to compete with 95%? You can't. And so the first thing is I thought if you combine the two things together into the multi junction approach, you can create a product that's different from everybody else's product, which is a solar panel. And even 10 years ago, All the solar panels look the same.

I mean, there are differences between them that subtly impact their long term performance, but they're not that different, which made it very difficult for the companies that sell them to differentiate on anything but price. But if you had a higher efficiency product, now you have something to differentiate yourself.

So the first concept was to have something which was different than what other people had. But then understanding, you know, the, the role of efficiency and panels in solar cells, the realization came in that you don't need more efficiency in the silicon range. There are products today that can make 20 percent panels, 22 percent panels, and there's thin film products from Cad Telluride, that make thin film that are reasonably efficient, but you need higher efficiency because the solar cell is actually only a small part of the panel's cost.

So, if you continue to drive down its cost, you actually don't reduce the cost of the energy. Only way to change that cost pro, pro, pro, is to raise the efficiency. And as it turns out, there's a lot of other good reasons to raise the efficiency, like let's take your roof on your new house, and you put in 22 kilowatts, what was the size?

It

was

17. 1 kilowatts. Okay, sorry, but that's a pretty big array, and I'm sure you took advantage of a lot of your rooftop space, but I'm sure you would have happily said, well, could I put more than that on? And the answer is, you can't with conventional technology because you're space constrained. So, uh, higher efficiency means you can put more power into the same area.

As it turns out, it's not just homes and commercial buildings that are constrained in space. It's the utilities. There just isn't a lot of available land close to the grid connections where you can put out these hundred megawatt, multi hundred megawatt utility installations. So you need higher efficiency and the only route, the viable route to higher efficiency Multi junction, right?

What do you mean that, that was described in 1960 by Shockley and Quiesser in their paper. But yeah, it is the only, and it's the standard route for, for solar cells that go into spinx. They're all multi junction, very expensive. A thousand dollars a a square meter, and sometimes a thousand dollars a watt type compound semiconductors.

But that is not a solution for the world. So multi junction just makes sense. And combining perovskite, which has the adjustable band gap and is low efficiency with the de facto silicon was the perfect match.

All right. So you can end up with a tuned panel that breaks what we're, like you just mentioned, typically you see what 20 to 22 percent efficiency.

Right. Okay. And your panels are 24 and a half percent, I think it is.

And that's our introductory product. The capability is much higher than that because if you think that silicon has achieved what's achieved since 1954, you know, 70 plus years of development, perovskite's achieved what's achieved in less than 10 years or around 10 years.

And the silicon efficiency limit, the theoretical limit, published in 1960 again, uh, is 29 percent. A direct bandgap solar cells limit is 33 percent. Today the record silicon solar cells, 27, 27 percent. That's unbelievable. Okay. So you got 27 out of 29 within 10 percent of theoretical. You're not going to get to 29 by the way.

Anybody who claims that, you know, is pulling your leg. There's always losses that are just unavailable or unmanageable. But to get to almost 27/29, today the record perovskite solar cells are close to over 34%. It's unbelievable, right? And again, in this sort of multi junction form, combining perovskite and silicon.

But the theoretical limit for that perovskite and silicon, 43%. We have a whole bunch of the future headroom. So that's why our roadmap takes this product, you know, well beyond 30 percent as, as a module. In fact, we tell people it's 27 percent in 2027, it's 30 percent in 2030. And Silicon, no matter what you do to it, can't do that.

So, this is really a transformative way to deliver higher efficiency, which we think helps to accelerate the adoption of solar. And no one, I think, except maybe the latest election winner, has any qualms about the deployment of, uh, of renewable energy. Sorry. I probably should have said that. I should have warned you at the beginning.

I didn't see exactly where

you're coming from on that. Oh, right. So, uh So, it's 24 and a half now, you're saying by 2030, it could be around 30%, um, so there's definitely way more headroom for growth with this kind of technology, this tandem approach because of how you can tune it and refine it over time.

One of the questions that came up on my team as we were pulling the kind of research together for this, this video we're putting together was on multi junction cells. You have different components, you have silicon on one layer, you have my perovskites on another layer. Right. Do they degrade at different rates?

Do they Well How do they behave

with each other? So, so, so the degradation rate of silicon is pretty well established because people are offering, you know, product warranties that exceed 25 years. And typically that means nearly a guaranteed minimum performance at the end of 25 years of typical outdoor life.

So, our first target was to make sure that we could match that sort of degradation profile. Now one thing to understand is, you know, when you do this combination of putting the perovskite on the silicon, effectively you're filtering the photons from the silicon because you're converting those high energy photons at the band edge of the perovskite, which is around 1. 5 to 1. 6 eV, so it's smack in the blue range. So once you've converted those, the rest of the photons below that band edge, make it to the silicon. But you've now used up about two thirds of them. So the contribution to the photocurrent of the silicon It's actually about one third, so you're

not as worried about the silicon's contribution after all, because the bulk of the heavy lifting is taken care of by the perovskite, but you still want that silicon to contribute to the overall performance.

So our goal has been to reduce the degradation or, or sort of prove the performance and life of the device. So the combined device meets that same kind of 25 year performance expectation. Another question that comes up, and it's probably come up in the work that you've looked at, well, but the sun during the day kind of changes color.

Well, no, of course the sun doesn't change color. What happens is, you know, the atmosphere has varying effects on what you perceive. In terms of the absorption of different photons in different parts of the day, different thicknesses of the photons transport from the sun to the solar panel. So during that change, doesn't the performance of your perovskite get altered?

And if your perovskite is getting altered, then how do you match this sort of photocurrents from the top and the bottom cells together? So these are all legitimate questions, but in the end, it turns out they don't have big impacts on the device. We sort of, we and others have figured out that you can match, because our device, by the way,

and it's important for some people to understand the distinction is what's known as a two terminal multi junction solar cell. So the perovskite is deposited directly on the silicon. So, when you're finished, the solar cell rectangle, rectangular, square, typical. It has two contacts, you know, a plus or minus cathode or anode, just like a regular solar cell.

It kind of looks like the solar cell, and therefore you can sort of install it into modules and connect it up in series like regular solar cells. But it also means that the performance of the top cell and the bottom cell from a current perspective have to be pretty similar because the device is two series diodes so the voltage is had but the currents need to be pretty matched.

But we worked all of that stuff out. And there are other people who are pursuing different routes where they should make the perovskite sort of in large format like thin film and then place it over, you know, a conventional panel. Like imagine taking your rooftop filled with, uh, your panels and placing another panel on top, the perovskite, and sort of boosting it.

And it's a great concept. It's sort of a great dream, but boy, now you get an extra weight, now you're going to have to have separate electrical inverters to deal with because, you know, the different voltages in different systems. We just decided back in 2014 that that was not the right approach.

Others continue to pursue that, we don't. That's fascinating.

One question that does come up when I'm staking on the kind of degradation stuff for a second, testing. A lot of people have questions around like, how do you test a panel to show that it's going to last 25, 30, 40 years in a short time frame?

How, how does that kind of testing work?

All right. Uh, so it's the basic question, of course. And remember, I was telling you that we tried to figure out where the major loss and degradation mechanisms were. So the only way not to wait out 25 or 30 years, uh, and Silicon, by the way, has waited out the 25 or 30 years.

So we're pretty confident that it has pretty good field performance in those panels I built 20, 35 years ago. Actually, they have very, in fact, they had no failures. They degraded over time, but they had no failures. But, so, the typical thing you do is accelerated stress testing. In fact, the certification protocols, known as the IEC protocols, are just that.

Elevated conditions, usually that means, uh, either light or temperature or combinations that place the, the panels in conditions that tease out in a shorter period of time what the performance might be over a longer period of time. So that's exactly what we do. Now, the standard conditions are you cycle the modules from, uh, from 85 degrees to minus 40 degrees.

Okay. And you do that many, many times. Or you place them at 85 degrees centigrade into a chamber at 100 percent relative humidity and sort of bake them to death. Or you do that with the addition of light. So we do all of those tests and then we do them even under harsher conditions. So what does harsh mean?

With higher temperature, we don't really talk about exactly what we do, uh, but our goal is to do something that basically tortures the device so that we can learn in a much shorter period of time. So our tests are designed to provide feedback for our learning in less than a week. So, we really, uh, uh, put accelerated conditions in terms of temperature and light to our devices to test them.

And then, whatever we see, then we try to either mitigate it, etc. So, our panels undergo those same standard tests, okay, which is what customers mostly expect and they expect it because the standard tests also include a component of safety to make sure that, you know, the product, uh, isn't a fire hazard, is not electrical hazard, uh, and can withstand, you know, a certain amount of environmental exposure in particular hail.

That's one of the, you know, the big problems that happens and by the way, hail exposure has gotten worse as the You know, climate crisis has gotten worse and people are suffering more hail damage. Uh, but that's, that's the effect. So we try to tease out that long term performance in short time periods and I think we've done a good job.

One of the things you were talking about before about because this is a higher efficiency panel, you need fewer of them. I'm assuming that's how, cause you're, you're, these are on the market. These are actually installed. They're providing, from my understanding, electrons to the grid right now. Fit. Because they are installed somewhere.

I'm not sure where they're installed, but.

But I can tell you a little bit about where they're going in or their details too. Sorry, I'll let you finish your question.

I was going to ask, like, these panels I'm assuming, we don't have to get into the exact costs, but like, I'm assuming per panel it might be a little more expensive than a competitive panel that has a lower efficiency, but when you're looking at the lifetime, the LCOE of the entire installation.

It's going to come out ahead because you need fewer panels to get the same amount of power output. So if you're looking for a hundred megawatt installation, you could, that's a lot of panels, a lot fewer panels you might need compared to a competitor product. So I'm assuming that is where the benefit from a utilities point of view comes in.

Right. For the utility, of course, first of all, the, the buyers of utility energy are actually, they don't care about the technology at all. Yeah. I mean, I use this phrase occasionally. They couldn't care if the field was filled with little hamster spinning miniature turbots. Is one. Okay. Sorry.

That's an image.

That's a great image. Okay.

But as long as it generated, they were, you know, reliable return on their investment. That's all they care about. But of course they do want either lower cost energy. Or, a better return, and the correct metric is, as you pointed out, the levelized cost of energy. In a flaw in most procurement behavior, and this is in almost anything due in the world, people buy on price.

So this industry has been driven by price per watt. And you go out and sort of, Oh, that's a little cheaper on the perovskite. It should not be your decision making. Just like don't buy a car based on its price, well, hence, you maybe want to do that. But you should look at its reliability, its insurability, right?

Or its maintainability, and of course, its fun factors and all those other things. And ultimately, all that should go into your decision making. But a lot of people walk in the showroom just buy what they like, or because they have the color. For the purpose of buying energy, it should be the levelized cost of energy, and unquestionably these panels cost more to make, because we start with silicon.

There is effectively a silicon panel that we've had to do something else to those silicon solar cells and add some more cost. It's not a lot of extra cost, but it's definitely more cost. And what we charge for them, well then that depends on what they're worth. And what they're worth depends on what is the energy that they deliver, this levelized cost of energy.

And I assure you that the levelized cost of energy of the product that we're offering to the utility customer is lower than what they can get in the products they're buying today. So that's what they're excited about. Of course, they want to test it out. And make sure our claims stand up to the performance.

And that's, and they also of course understand that not only do we have today's performance, but we have the promised improvements that we'll deliver as the product is further developed in the next, you know, five to 10 years. So, this is, we have manufactured, sold, and delivered hundreds and hundreds and hundreds of utility modules to a large utility customer in the United States.

And the key parts of that, well the statement I just made is sold. By the way, that's very important for a startup company, the word sold, because it means, in fact, we've been paid for, because they had to pay on, on, on shipping, I think, not even delivery. They paid when it was shipped. Uh, they have been delivered, so that's good.

They're not yet installed because they're going into a much larger installation. They're going to, I don't know, 20 or 15 megawatt grid tied installation where we'll share a portion of that field. So they're on a conventional tracker installation. They're an elevated installation in the U. S.

And they will be monitored with the other, I'm not sure what else is in there that that's their choice, but they'll be monitored for their comparative performance at the same time. But it is grid tied. So we will be generating electricity, I'm not sure when it goes online, probably towards the end of the year, but they, they are already, you know, on site in their shipping containers.

Yeah, they're on site

getting installed.

Ten years for us, from concept, which is 2014, our first demonstration is 2015, product delivery, and it sounds really long, but it, uh, it's still pretty good.

I was going to say, you say it sounds pretty long, and I would say most viewers and people that watch my videos.

There's a thread in the comments a lot. Oftentimes when I talk about these, here's a research team at a lab at a university that did something really cool and they're like, Oh, well, we'll never see it. And it's like, well, it might be 15 years before you see it. I don't think a lot of us have a concept as to like the time scales it takes to go from like a lab idea to early production to full scale production.

It takes a lot of time. So that ten years actually to me sounds very reasonable. We've pulled up.

So for me, because I'm a relatively impatient person for those who know, you know, it's logger. And of course we were hit by things, you know, COVID and supply chain and the Russian invading Ukraine and all this stuff, which in some cases helped because it pushed people to resurrect energy security as a concept to trying to do more sustainable energy.

But it's still hurt in terms of extra delays. But in the history of photovoltaic and solar cells, it actually is pretty fast. But what we need to get people to expect is this material now is so recognized as the future of solar. And I think it is recognized that it will be incorporated into most solar patents.

And I think for the next 10 plus years, through the multi junction approach, and this is the critical time period for our planet. What are the net zero targets? Well, it depends on who you look at anywhere from 35 terawatts to 70 terawatts, right of what we need. And what do we have installed today?

Well, I don't know, two terawatts, both of, of, of, of sustainable, uh, uh, energy, wind and solar predominantly. And what's the manufacturing capacity? 1. 1 terawatts, 900 which is gigawatts of capacities in China, by the way, that's a separate issue. But regardless of the capacity, so when people say, oh, we have too much capacity, it's over built, wrong.

To achieve that target of 35 terawatts, we need to build and install at the rate of two to three terawatts a year for the next 10 or 15 years. First of all, that's a tremendous business opportunity. Everybody should be drooling that's part of this business. It also means we can't do it by ourselves. So we're just absolutely open to, you know, doing partnerships and collaborations and joint ventures with anybody.

We want to see deployment like you did, as you've said in some of your videos. The all electric world, by the way, we should talk about some things that you could also try out in your house. Some other ideas sometimes we can talk offline. I think one key thing that you could have done is put a DC grid, these DC bus in and skip your reverse.

Yeah. I put a DC bus in my house 35 years ago. Oh, wow. Okay. Because everything in your house effectively runs off DC. I mean, it's almost nothing except a few synchronous motors. And why go through the conversion losses of the inverters?

Yeah. Yeah. No, it was something that was on my, my like possibility list, but I kind of wrote it off as like, yeah, it still feels like from a consumer point of view, it's a little tougher to find the things that would work with

it.

You got to sort of do it yourself type stuff, but boy, it's another opportunity. And of course the big data centers do that. You know, their computers don't have power supplies. There's no AC to DC power supply at a data center, Dell or whoever makes the computers. They're direct connected to the DC buses.

So, yeah. I mean,

well, you just said a second ago, it does tie into one of my follow up questions I had for you, which was, I know Oxford PV is ramping up their manufacturing, how many of these you can actually make, but you just made the point of like, even if you guys, opened up four new factories. You're still not going to be able to supply enough.

So it sounds like you are open to licensing and partnerships to try to get this technology out there as fast as possible.

Yeah, absolutely. And, and, you know, we have something like 600 patents, which isn't the point of it, but we've obviously figured out things that not everybody has figured out.

Otherwise, you know, we wouldn't be out there with a commercial product, I think, but there's hundreds of companies doing this and 10, 000 plus people working in this field. I mean, this is the stuff people want. It is absolutely going to be done across the board and solved. And you know, first of all, for me, it was been, you know, working in solar more than three decades.

This is my dream and vision. Don't do it just because it's fun. I do it because I want to see us have a successful, you know, energy transition and nothing beats solar. I

mean, that, that ties in nicely to one of my final questions I had for you, which was like kind of your personal takeaway on a personal note.

Like. What excites you the most about Oxford PV's role in this energy transition and what legacy are you hoping to leave behind?

Solar is not new, right? You know, what, what some of my wines are four and 70 X the joules of energy are beamed to the earth's surface every 88 minutes, you know, it's enough to power the planet, you know, for an entire year.

Often a quote, uh, Edison and his quote about, you know, solar energy, I hope we don't wait till fossil fuels run out before we do it. It is the perfect energy source and just think effectively it's like what's happened with the internet. The cost of, you know, transmitting the internet has dropped dramatically.

The cost of storing things has dropped dramatically. You know, 20 years ago it became cheaper to store things digitally than on paper. And as soon as you saw that barrier crossed, you should say to yourself, the future is always electronic storage. And there was an opportunity to understand what was going to be higher density storage and opportunities there.

It's the same thing with solar energy. The energy today is recognized as the cheapest form of delivered and distributed energy in most parts of the world, and far cheaper than, you know, coal and stuff, especially if you factor in the impact of hailstones and other environmental benefits. What can you do with really cheap energy?

Well, you can start to do things you didn't think about, like what's a high energy intensive thing? Desalination. What's another big world problem? Water. Water, water everywhere, not a drop to drink, unless you can desalinate. And now you can produce, you know, energy at a cost that makes desalination viable and address another one of the human condition challenges.

Just like there's still 800 million people without electricity, same pan around the world, you know, Sub Saharan type places, PV is the only and most effective way to deliver those solutions and who knows what, what, uh, what people, you know, and, and, and talent work in those 800 million people. So, this can change the world and save the world.

So, do I think we're the ones doing it? No. Do I think we can help? Absolutely. And, and I think, uh, you know, that's, that's really the thing that I'm most excited about, being part of that, uh, that path.

My final question is, I like, I like asking this of everybody I talk to. What advice would you give to somebody that is looking to get into sustainable technologies or renewable energy or like young engineers and scientists, like what advice would you give them?

You know, it's, it's probably the same advice I provide to anybody. You need to get involved in these activities at a young age. I mean, the, the, really the fix to this goes back to schools and things. I mean, I got exposed to sort of gizmos and gadgets, you know, when I was young, okay, partly because I came from an engineering family, but that does make a difference.

And if you look at, you know, some of the recognized, you know, technology leaders in the world, you know, Gates and others, and look and read their stories about their histories, they also got exposed. Uh, maybe because they were a little luckier where they lived, but they got exposed earlier to these things.

So somehow you got to get exposed and if that means pushing your parents, you know, to take you to museums or other places or even asking for different kinds of programs at your schools, do it. If you don't play around with this stuff, how can you learn what it feels like?

That's great advice. I love that.

And I agree with it completely. Is there anything else we haven't touched on that you'd want to touch on?

Well, I don't know. I, first of all, I'm sorry if I talk too much and I probably extended my answers well beyond the your ability to cut and edit into, you know, proper soundbites, uh, and, again, come visit us, or let me see your house.

Yeah, if you're in Massachusetts, give me a call. By the way, that house, uh, that I built wasn't just a regular photovoltaic house, it was a photovoltaic thermal house. Oh, wow. So I built photovoltaic thermal solar panels. And I bought 3, 000 round, 1 watt, monocrystalline silicon solar cells from Arco Solar.

They were supposed to be $40 each, and I got them for $10 from my friend, Charlie Gay. Uh, it was a long time ago. They carried them back on the plane from Chatsworth, California, in these styrofoam boxes. And I wrote a check for $33, 000, which was a lot of money. And I brought back these boxes. I said, you drop that stupid box.

You have $5, 000 of broken solar cells. And I spent an entire summer building the modules, gluing the solar cells, laminating and soldering by hand. And I glued little aluminum heat sinks to the back and then I create air channels and then I put in 20 tons of granite rock that I imported from Illinois so it didn't have a high radon signature, circulated that through the panels, used air to air heat exchangers and air to water heat exchangers for the storage.

And had a little relay logic thing that decide what to do and the overall energy conversion is 60%. 10 percent from the electricity and 50 percent from a relatively poor, you know, solar thermal panel, but still pretty cool. And in a modular home type we built, all sealed up, where I was worried about, you know, contamination from formaldehyde and those things like that.

And I add a heat pump, and the first grid connection, utility tied, synchronous inverter in the state. And it took me nine months to compel the state, to gimme permission to do the connection . So, wow.

You are a trailblazer. You, you are a

trailblazer . So, so this is really, really embedded in what I, you know, like to do.

So, yeah, hopefully it, uh, it helps us, you know, try to toss a solution. So anyway, that's why I admire what you do. Every single thing you've done looks great. So I appreciate that very much.

Thank you to Dr. Case for sitting down with Matt, and thanks to all of you for sitting down to watch or listen. What did you think of this conversation?

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