Inaugural Lecture Series: Professor Christopher Sansom video transcript

We begin with the University of Derby three hills logo in white fading in on top of a dark blue background. Text appears underneath which reads “Professorial Inaugural Lecture Series: Save the World and Find a New One by Professor Christopher Sansom”.

We fade to black for a moment before a shot of a lecture theatre fades in. We see people sitting along the front row and a stage is in front of them. At the back of the stage, there is a large projector screen which is showing an image of the university south tower with the title of the lecture appearing in front of it alongside two pictures; the first shows a close-up 3D render of the sun and the second shows Chris Sansom standing in front of two large solar panels.

We see Paul Lynch walk into the frame. He is wearing a long, red, academic robe. He is a tall man wearing glasses and short hair. He stands at a podium at the front of the stage and begins to address the audience.

[Paul] Good evening colleagues and welcome to the latest in the inaugural lecture series. Tonight, Professor Chris Samson will be talking about "Save the World and Discover a New One", which fits very nicely with his job here at Derby as our theme lead for zero carbon. What I'd like to do now is to introduce you to Professor Mark Jolly from the University of Cranfield who will introduce Chris to us.

We see Paul leave the stage and sit down in the front row of the audience as Mark walks onto the stage and stands at the podium. He is a medium-sized man wearing glasses and a black academic robe with a red collar.

[Mark] Thank you very much, Paul. Good evening, ladies and gentlemen, it's really wonderful to have been invited here to introduce Chris with whom I've worked in Cranfield for very close to 10 years. Chris was brought up in Wales but makes no claim to be Welsh as he was born in Solihull in Warwickshire and his parents were English. But they moved to Rhyl when he was two years old. Chris's father was an aircraft engineer at what is now Airbus, and his mother ran the boarding house where they lived.

So, at school, Chris loved sport as much as science and he even played hockey for Wales despite being English and at county level tennis. In science, he liked anything to do with heat and light and says he's been working on that ever since his A-levels. As an indicator of things to come, he bought a four-inch reflecting telescope and joined the British astronomical society using the money he'd earned during the school holidays by stacking deck chairs on Rhyl beach and working as a waiter.

Chris eventually obtained his degree in physics from Liverpool University and his PhD from the University of Sussex, carrying out research on the topic of infrared detector materials. His PhD was funded as a collaborative award in science and engineering (we call those case awards nowadays or even I case) and it was Plessy research labs that offered him a job in their infrared detector research group after his PhD and who also turned me down for a job after my PhD *laughs*.

So, Chris moved to the GEC research labs after two years and stayed with GEC Marconi for 20 years. His research at that time was mainly on manufacturing focusing on the fabrication of gallium arsenide semiconductor devices for telecommunications applications. Most of this work was obviously carried out in clean rooms.

For Chris, these were very interesting times; a number of government ministers toured the facility and on one notable occasion the prime minister of Malaysia came, and Chris notably gave him a tour of the clean rooms, accompanied by two guards with automatic weapons which Chris had to wipe those down with a lint-free cloth before allowing them into the clean rooms. To this day he does not know whether they were loaded.

When Marconi collapsed in 2004, he spent some time in a number of different positions, as an operations manager, a quality manager and as an engineering manager for both Amazon(Of all places) and Perkin Elmer. At Amazon, he was the operations manager on the night shift at Marstongate (which is very near Cranfield University) which was the only amazon site in the UK at the time. All the parcels coming off the night shift between2004 and 2006 were his responsibility, so any outstanding complaints from that time should be sent to him at the end of the lecture *laughs*.

With four parcels per second coming off the lines at Christmas time and 400 staff to manage, Chris says he learned to make very quick decisions. Eventually, in 2007, an offer came to join academia as a senior lecturer at Cranfield University and whilst there he began in what was called the precision engineering institute as the knowledge transfer manager and was the MSC course director. He developed his research portfolio around waste heat from machine tools and energy harvesting generally and then, eventually, into solar energy. After a fortunate meeting with academics in Egypt whilst on holiday there, he discovered concentrating solar power (CSP) which has been his research focus ever since.

In January, Chris told me he was about to retire because I was essentially working very closely with him, and he'd been part of my setup and we were still very close and we co-supervised some engineering doctorate students. He was going to cut back his hours but then he was headhunted by the University of Derby, and he told me it was "too good an offer to refuse”, so he says he's left to be the head of the new theme in net zero carbon which is one very close to my heart and my research as I have some very big research portfolios from the UKRI in this area. The latter role overlooks the university as a whole in terms of net-zero and gives him the opportunity to build something completely from scratch, so Chris's retirement will have to go on hold for a while.

He's married to Sarah who used to be my information specialist at Cranfield and is a wonderful woman and they live together in Norfolk when he's not in Derby or North Wales or somewhere else with some strong direct sunlight. But now, it gives me great pleasure to invite Chris to share his thoughts on how to save the world and discover new ones. Chris.*Applause*

Mark leaves the stage, and we see Chris Walk in. He is wearing a blue academic gown and a black hat with a red tassel with glasses.

[Chris] Gosh, how to live up to that introduction? That's going to be hard, isn't it?

Thank you very much, Mark. Yes, I had a great time at Cranfield University and I'm looking forward now to my new career here at the University of Derby. I'm very happy to be here. When I look at the title, it sounds very pompous doesn't it? Please don't think that I'm going to save the world on my own because I'm not, that won't work. But it just occurred to me when I was thinking about what to talk about and how to frame my career so far and that was...that you used to hear people say things like "well, we can either save the world or we can do that" but now I think we should think about saving the world and finding another world. That's important in that title because there are opportunities now both to improve the world that we all live in for obvious reasons because of climate change, greenhouse gases and so on, but also as you will see from the latest ground and space-based telescopes, there are opportunities to look for new worlds in the future and it's by sheer chance that my career has touched both of those things.

I'm very envious of people who say that they planned their careers because I certainly haven't been able to do that. My career has been all over the place and you've got a good idea from Mark of some of those things. I mean, two years at Amazon is not something you would plan into your career perhaps as a scientist, but at the time, they were recruiting scientists because they felt that some of their processes demanded a scientific approach so that's why they recruited us.

Anyway, I'll get on with the talk and perhaps you will understand how saving the world and finding new worlds have been part of my career so far.

A new slide appears on the screen which shows two pictures of two different buildings. On the left of the screen is a picture of a building in Caswell which is an old, ornate building with a large, well-kept garden in front of it. On the right, there is an image of a large, industrial warehouse building covered in snow. There is text above these images which reads “My first job after leaving the University of Sussex –1980. Allen Clark research centre and the Plessy research centre: Caswell, Towcester, Northants. Built-in 1840, Plessey moved research to Caswell house from Ilford in 1940. It is a business park today, but the building still remains”

[Chris] So, I did start in research labs, I started at the Plessy research labs which you can see on the left at Caswell. Plessy moved their research from central... well, it was actually in Ilford in 1940. Ilford in 1940 had some problems with planes flying over dropping bombs on it so they thought that was not a very good idea and so they moved their sensitive radar materials research to Caswell which nestled in a little valley. So, I started at the Plessy research labs, working on infrared detectors. It looks very pretty in that picture on the left, that's what it looked like the winter, I took that in the winter around about.... must have been around the mid-70s, I suppose that sort of time. That was one of the days when we couldn't get into work because it was snowed in, so, there's not much to do in Caswell on a snowy day so we decided to walk to work anyway. It took us about four hours to walk there and four hours to walk back and that was a day's work done as far as we were concerned. It's still there, it's a business park today and so, you can still go there and there's still some interesting research that's done there.

The slide changes and on the right-hand side of the slide we see an image of a large, red cylinder with a valve on one side; the object is later revealed to be an infrared detector. To the left of the image is a graph which shows the development of various types of infrared detectors from 1950 to 2020. Directly above this graph, we can see an electrical diagram showcasing the various elements that go into making an infrared detector.

[Chris] As I said, I worked in infrared technology and if you look at the timeline for infrared detectors, I worked around this time (he points towards 1980 on the slide) I was actually a bit later than 1970 so I'm not quite as old as this might indicate, I worked more around that time on lead telluride which was the led tin telluride which my PhD was on. So, I just continued working on my PhD work in the research labs on infrared detectors and they looked something like that. That was a single element infrared detector which peaks at defectivity around 10.6 microns which, the human being radiates at about 10.6 microns of wavelength, so they were looking for people. So, this is unfortunately for military applications, looking for people hiding on battlefields. I'm pleased to say that my military work did not last too long, and I was able to move on to more peaceful applications.

The slide changes and we see a new one appears which is titled “A Move to Hirst Research Centre, GEC Research Labs, North Wembley (1983). On the slide can be seen two images of the same Victorian building with large, hatched windows several decades apart. Beneath these images is a subtitle which reads “GEC Research Labs (east lane, Wembley), the 1960s (left) and 1980s (right)”

[Chris] I then moved on to GEC research labs, as mark has mentioned, this was in north Wembley. Sadly, this is no longer there at all, and I haven't had the heart to go back and look but I think this is a block of flats now. It was one of the main research labs in the UK right up to the 1980s and early 90s. That's a picture that was taken in the 60s and when I was there in the 1980s when they did industrial research, a bit like university research but without the teaching, if you like.

We see the slide change to show two images. On the left image, we see a group of people in a clean room wearing blue rubber suits and covering their faces with masks and a blue hood. They are gathered around a high-tech-looking monitor and are discussing what they can see amongst each other. In the right image, we see a collection of semi-conductors and circuitry that have been joined together to form a metallic wafer which creates a rainbow effect across its surface in the light. There is text above these images which reads “GEC research labs (later relocated to Caswell)–MMIC semiconductor wafer fabrication for telecoms applications. My job titles over 20 years included senior research engineer, production manager and process manager. The company name changed almost as much, from GEC to GEC-Marconi, to Marconi and finally to Bookham technology”.

[Chris] In that one, I was working (as Mark said) in clean rooms. I was working in clean rooms at Caswell too in the semiconductor industry, so that's basically how I started working in the semiconductor industry. Wearing these bunny suits as we used to call them and working in yellow light most of the day, so you'd come out into the daylight and think "gosh what's that?" since you'd been working in artificial light all day long. It was a lot of fun, and we were definitely considered to be very much state of the art in what we were doing, we were working on something called MMICs, monolithic microwave integrated circuits. You have those in your phone now, you'll have gallium arsenide and indium phosphide devices in your mobile phones today, but they were quite new at the time.

I said I worked on heat and light and even then, I managed to find some way to work on heat and light because I worked on what we called wafer steppers which transferred the patterns from the masks onto the wafers using a deep, ultraviolet light, so that was light. I've always managed to find... no matter where anybody has put me (not always by choice) I would always find a way somehow to get involved in heat and light because I think they're easy to understand.

We see the slide change to show a series of logos for places, including Cranfield University, OpTIC and the University of Cambridge. Below these logos, we see a collection of text that details Chris’s entry into academic work which reads “Entry into academia in 2007, senior lecturer in ultra-precision engineering, knowledge transfer manager, course director of MSC in UPT, short course manager and outreach manager”. To the right of this text, we see an image of a large, modern-looking building consisting of large, brushed steel pillars and concrete. Above this image is text which reads “Integrated Knowledge Centre in Ultra Precision and Structured Surfaces, EPSRC”.

[Chris] So, after my little sojourn into Amazon and various other places when Marconi, unfortunately, collapsed along with the company of GEC which was a real shame for the country I have to say because GEC had around 100,000 engineers or something and we were all basically out of work one day, a number of us working in research labs. The obvious place was to end up in academia because we did research, and I was lucky enough to be offered a job at Cranfield University as Mark mentioned. I had all these wonderful titles as you can see like senior lecturer, knowledge transfer manager and of course, director. I was supposed to do all of those things but I'm not sure I did all of those, I tended to concentrate more on the senior lecturer bit, and I suppose the short courses are what I tended to do mostly because I liked working with the industry, I liked working with companies which is very much part of the job I'm doing here of course, so that was good training for that.

I like working with companies, doing knowledge transfer and I also like teaching students as well from the developing master's courses in this because in Cranfield there are no undergraduates, only postgraduate, so it had to be master's and PhDs. So, I was part of this new development called the integrated knowledge centre, the IKC. It was government-funded, excerpt funded and was around ultra-precision and structured services which sounds very grand. It's really advanced mechanical engineering and I went for the interview, and they said, "are you interested in the job?" and said Well I'm not an engineer, I'm a physicist by training so I don't know anything about machine tools, and I don't know anything about ultra-precision surfaces. They said, "oh don't worry, you'll pick all that up", so I considered myself rather fortunate to get the job.

The slide changes and we see Chris standing with a group of students in front of a large, high-tech-looking machine which is branded with the Cranfield University logo. The title of the slide reads “MSC In ultra-precision technology and applications –first cohort 2007/08”.

[Chris] It soon became clear that I needed to do something more than teaching my students.

This is the first cohort, actually, that's me on the right looking a little younger but not that much younger. That's my first cohort; we had no students on the course at all when I joined. We joined in... I think it was April I joined, and the course was due to start in October and there was no course and no students, so my job was to develop the course and get it through all the approvals very quickly and find some students. These students, I found at recruitment fairs generally looking for work and I persuaded them that they really wanted to be the world expert in ultra-precision structured surfaces. So, if I'm good at anything it's probably selling because they all came on the course. I'm pleased to say that I keep in touch with most of them and they're gainfully employed, so I don't think I misled them.

The slide changes and we see a collection of images showcasing various high-tech materials such as solar panels, semiconductors and large, concaved mirrors. The top of the slide contains text which reads “The importance of ultra-precision technologies and surfaces. Many next-generation technologies and products will be reliant on ultra-precision and structured surfaces. Such surfaces provide fundamental product performance and enable new methods”.

[Chris] So, ultra-precision surfaces, what do we mean by that? I just thought I'd divert into this for a second because it's quite interesting.

In terms of finding new worlds, precision surfaces are used for a whole new generation of products in a number of different areas such as large mirrors... that's actually a lens from work, from a wafer stepper in the semiconductor industry. That's obviously a wind turbine, that's an artificial joint surface which is important to the person actually, using the artificial joint and you've got large area displays (I'll come back to that one) ... And obviously, in aeronautical engineering applications, the surface can make a big difference to the performance of some of these types of products and that was what the IKC was all about.

The slide changes and we see various large pieces of machinery shown on the slide. Below these images are some texts which read “Ultra-precision surfaces –key equipment 2007. Accuracy capability to 1 part in 10 to the power of 8”.

[Chris] These are some of the machines and tools that were used, and this is one which actually, I'll come back to again because it's called a large coordinate measuring machine. At the time, it was the most accurate large CMM in the world.

This up here is called the grinding machine or the box grinding machine. It's called the box because it looks a bit like a box, but it's also called a box because it stands for big Optics, very clever, so that's big optics. This, when it was built was the world's most accurate large grinding machine and the two of these together made ground mirrors for very large ground-based telescopes, that's what it was for which is really exciting. The biggest telescopes in the world had their mirrors ground on this piece of equipment.

These machines were built at Cranfieldby the way, that one wasn't, you can see it's got lights on it but these two were actually built at Cranfield. The nano centre was used again for parts for the James Webb space telescope, so by ultra-precision, we mean one part in 10 to the eight which is scary, that is amazing if you think about the meter scale, that hundreds of angstroms, that is incredible. These machine tools could machine metals, glass, whatever so that was that.

I wouldn't claim to be a precision engineer, I've already told you that I'm not, but I was definitely part of the activity and proud to be part of that activity and doing such interesting work.

The slide changes and we see three images appear. The first shows a complex cross-section diagram of an image slicer mirror, the second shows a large machine used for grinding mirrors and the third shows a 3D render of the James Webb telescope floating through space, which is a telescope with a large, golden solar sail which expands outwards. There is another, a smaller image of a metallic object which resembles the shape of a light switch to the right of these three images. Above the smaller image is text which reads “James Webb telescope, launched December 2021. Image of a MIRI image slider below. Understanding the formation of stars and planetary systems, the evolution of planetary systems and the conditions for life to exist”.

[Chris] This is part of the"find new worlds" if you like because the James Webb space telescope (which, as you know was launched on Christmas day last year) is looking for Earth-like planets around nearby stars, amongst other things of course. It's an infrared telescope and Cranfield produced this thing, a number of these actually, these are called image slicers for the MIRI. The MIRI is the mid-infrared instrument in the James Webb space telescope. It's an image slicer and then there's a combiner in here as well which we also made.

So, that is one of the things that I guess touched my career in terms of trying to find ways in which we can find other worlds if you like, other planetary systems around nearby stars that might support life and might support human life. I mean, this is a NASA space telescope and believe me, NASA does not come out of the U.S for parts if they don't have to, so it shows you the expertise that there was and still is at Cranfield today in precision machining to be able to make that part. They were delivered on time and they're now in space. So, I was really proud to be part of that.

The slide changes and we see two images. The first of these images shows a 3D render of an extremely large telescope while the second shows the construction of the extremely large telescope taking place in a desert. The title for the slide reads “ESO, European Extremely Large Telescope (E-ELT), this will be the largest telescope in the world once completed.

[Chris] Also, at that same time, we were working on these large mirror segments for what will be the largest telescope in the world when it's built, it's not finished at the moment, and this is the “European extremely large telescope” or the E-ELT. Astronomers have a very odd sense of humour, you have to remember that they don't get out at night because they're up there in their sheds looking at the stars, so they have a weird sense of humour. We had the LT, which was the large telescope,
then we had the VLT which is the very large telescope, now we have the ELT which is the extremely large telescope and the one that was never built unfortunately was the OWLT. The OWLT is a good name, owls can see it in the dark of course but can you guess what the OWLT stood for? The overwhelmingly large telescope *laughs*.

It was designed but the OWLT was never built but it's a nice story, isn't it? The overwhelmingly large telescope. Anyway, we'll have to make do with the extremely large telescope for the time being. It's an order of magnitude better than any other telescope or it will be when it's built, and Cranfield's job was to grind and... I'm saying polish but it wasn't, it was to grind and flatten out after grinding but I'll say polish. We actually had a different technique for the grinding and polishing of large mirror segments for the E-ELT, that big box machine I showed you where the grinding machine for that and then it was polished either by the kemmer mechanical polishing or by a plasma technique which we developed for the polishing side.

The large CMN actually measured it because if you're going to make precision parts you have to be able to measure them,sothis again was the other part of "finding new worlds" if you like because the EELT is looking for exoplanets as they call them, earth-like planets. We'll be looking for Earth-like planets around distant and nearby stars. That's obviously being built at the moment, and it consists of the primary mirror. It's got five mirrors in there, believe it or not, bouncing light backwards and forwards. The main mirror is a 39.3-meter mirror but it's not a single mirror, it's got 980 think at around 1.4 meters across in a hexagonal shape to make up that that primary mirror that looks like it's one mirror but it's not, it's segmented and it has four other mirrors as well that bounce the light until it reaches the focus. Very exciting... and in the Atacama of courses you would expect, usually these things are on top of mountains and deserts and so on and yeah...I guess that's quite interesting. Bear in mind, I spend a lot of time in deserts, now that's...that's going on in the desert as well, so that's the part relating to "finding new worlds" really.

The slide changes and we see a diagram of a part of an energy harvesting device. There is text on each side of the box in which the diagram is placed which reads “store, re-direct, transform and convert”. The slide’s title reads “Research Topic –Energy Harvesting from Machine tools”.

[Chris] I had to do some research though while I was there, and I decided to work on energy harvesting which is what Mark alluded to earlier. So, I was looking at how we might harvest some energy from these machine tools but that's how I started out in energy really.

The slide changes and we see two images, the first shows an ariel shot of Cairo, a city in Egypt and the second shows Chris standing with various academics from the University of Helwan in Cairo. The title of the slide reads “On holiday in Egypt –2009 Helwan University (Cairo), Invited lecture on ‘Application of Precision Engineering and Energy Harvesting”

[Chris] That soon led me to look at energy more generally I suppose along with energy wastage. How we can use less energy and so on, and it was then that I had this famous holiday in Egypt, everybody knows about these days when I went on holiday to Egypt and invited myself into the Helwanuniversity in southern Cairo.

It's not the university you would normally go to, it's certainly not for tourism. It's in the dustiest, grimiest part of Cairo you can imagine, but I was happy to go there, I gave them a lecture on precision engineering and they looked a bit aghast and at the end, they said "well thanks a lot but I don't think we're really into precision engineering for large telescope mirrors in the dusty parts of southern Cairo, but we are working on concentrating solar power, are you interested in that?" I said I have no idea what that is, so they told me, and they said, "we're writing a proposal at the moment for a big EU project" and I said that that sounds interesting, and he started to talk to me about that.

Believe it or not, that holiday was how I started working on concentrating solar power. So, as I say, some things are planned, some things happen by accident and that certainly happened by accident. They put us up at Helwan university by the way overnight and I don't think this guest room had been used for about 10 or 15 years. Everything was covered in dust, everything in the room was covered in a thick layer of dust and they'd very kindly put some fruits and drinks out for us as well, so everything is covered in dust but you could have an orange in the dust, you could have an apple in the dust or you could have water in the dust, but you have to have dust because it was everywhere, so we didn't eat any of the things.

The slide changes and we see four images of different types of concentrating solar power which is listed as; “Trough” which shows a traditional solar farm with solar panels covering a large area of land, and “Fresnel” which is a similar-looking solar farm except the solar panels are curved, “Tower” which shows a field of mirrors aiming sunlight up towards the top of a tower and “dish” which shows one large satellite dish with mirrors covering its concaved surface. There is text above these images which reads “Concentrating solar power (CSP) Solar thermal concentrating systems for; Electricity(energy generation), heating and cooling, desalination, water purification and industrial process heat”

[Chris] So, what they were talking about was this. This is concentrating solar power, so this is where you take direct sunlight, and you use very large mirrors to direct the sunlight onto some kind of focal; either a focal line in this case with a parabolic drop or up there if you have heliostats around the tower as they're called. These mirrors direct sunlight to the top and it's a power station basically, just like any thermal power station after that. Once you heat up something in your absorber you then have the basin that you can generate steam in for a steam generator and then, through a turbine, generate electricity.

So, they're power plants but they use light instead of burning coal or fossil fuels and so on and that's what I got involved with. Believe it or not, you won't find any of those in the UK because there's no strong, direct sunlight, it's not good enough, so it has to be a hot and sunny country. So, I tend to go over too hot and sunny countries a lot and you'd be surprised how many people wish to accompany me on those trips *laughs*.

The slide changes and we see a new slide appear showing five new images. The first image shows the Greek historical figure, Archimedes, using a large mirror to reflect the sun and burn an incoming fleet of ships, the second image shows a lighthouse on a seafront, and the third image shows a close-up of a plaque on the side of the lighthouse which reads “world’s first parabolic reflector 1776”, the fourth image shows a close up of a solar panel in a solar farm and the fifth and final image shows a solar tower generator or “heliostat”.

[Chris] These parabolic reflectors that we spend so much time working on are not new, in fact, concentrating solar power is about 100 years old but because of climate change and because of the need to reduce greenhouse gas emissions and so on they've suddenly found their time in history. You can go right back to Archimedes who (it is said) burned the Roman fleet using parabolic mirrors, not lenses but mirrors. So, you can see how far back we all understood the power of the sun from magnifying glasses and so on, especially when we were young.

But Sarah and I were in Hunstanton a couple of weeks ago and we found this where Hunstanton claims to have the world's first parabolic reflector. So, I think that's a rather bold claim, but nevertheless, the interesting thing is of course that it's the only part missing from the lighthouse today, so the light has long gone from the top there but as you can see, these things have been around for quite a long time, and their time has finally come.

The slide changes and we see an image of two large energy storage tanks in the desert, which appear as two, large, brown cylinders surrounded by pipes and industrial equipment. Surrounding this image is a series of complex diagrams showing the inner workings of these storage tanks and at the bottom of the screen is a formula that describes the process in terms of physics.

[Chris] My job in this project that the Egyptian people very kindly let me take part...It started out as a thermoelectric device (energy harvesting again) collecting waste heat from one of these very large storage tanks here where they stored the heat transfer fluid that's heated up in these pipes here that the sunlight focuses on.

So, I started out and they said this would be about a 50,000-euro project, and I thought that this was an opportunity though because I'm working on large mirrors remember and these are all large mirrors, so I thought "I’ve got the most accurate CMN in the world, I could measure these mirrors more accurately than anybody else." So, by the time I'd finished (this is sales again, isn't it?) selling our capabilities, we were in this project for three-quarters of a million euros. So, it suddenly became the first of many EU projects that I then worked on.

The slide changes and we see an image of a solar tower installation with various mirrors laid out along a large section of the desert. Surrounding this image are various diagrams describing the process in more depth as well as two images of a measuring device for measuring the alignment of these mirrors. The title of this slide reads “Characterisation of CSP Collector Surfaces” and there is a small text box off to the right-hand side which reads “Use photogrammetry to establish shape errors in the parabolic form”

[Chris] So, we developed a technique to measure these mirrors, the mirror facets because they're in individual facets to measure these on the CMNas you can see in that right-hand picture. And, we also developed a photogrammetry technique using one of my PhD students. That was his work, to measure the shape of the mirror. So, we can measure the shape of the mirrors very accurately in the lab and measure the shape of them actually in situ as well, so this became something that we started to take around the world.

The slide changes and we see various images of Chris in Egypt. Two feature Chris measuring and standing in front of one of the mirrors and the other two show the size of the facility in the desert and the central building of the facility which features a building shaped like an upside-down pyramid.

[Chris] So, here we are in Egypt which is where this demonstration plant was built. You can see it's Egypt because they've got pyramids in the top left of this science park, and for some reason, they built one upside down *laughs*. I had no idea why and this is what it looked like, so that was looking in one direction and if you turned around it looked like that in the other direction and that's where we built the plant and there's me with one of my colleagues from Egypt measuring the reflectance of one of those mirrors. So, we set ourselves up to provide this service of measuring the shape and the form of these parabolic mirrors and also the reflectances as well, and we were asked to qualify those mirrors when that plant was built.

If you go to that plant in Abu Gorab, you're not far from El Alamein and Alexandria, and the plant is open, and you can go and look around it and you'll see that it's got the Frankfurt university logo over the top. The one drawback of this is that you need a lot of land to build these CSP plants. But, fortunately, they're usually in deserts where nobody cares, their land is cheap anyway, but if you tried to build one of these in California (which we have, there are some in California), that tougher because the land is expensive there.

The slide changes and we see a map of the world with the hottest countries highlighted in red and yellow and the coldest countries shown in green and blue. The title of the diagram reads “Direct Normal Irradiation”.

[Chris] If you look at the areas where we can build them then they are in what we call the solar belt, which is mainly between the two tropics, not necessarily equatorial because it's too wet there but around all around California, Nevada, Arizona and so on. South America, South Africa too and all across Spain, the Southern Mediterranean, the Mena region, North Africa, the Middle East, India, some of China and Australia is very good as well. These countries have CSP plants, you may not have heard of them or seen them but they're there.

The slide changes and we see an image of several parabolic mirrors stretching out across a large section of the desert. Above this image, there are two pie charts. The first chart shows the distribution of CSP plants in Spain in 2014, with parabolic troughs taking up 94%. The second chart shows through plants with thermal plants making up 82% of those plants. At the bottom of the page, there is a text box which reads “2305 megawatts in operation in 2014”.

[Chris] So, just very quickly, I'll just show you a few pictures of these plants. So, there are 50 of these CSP plants in Spain alone, mostly built around the same time around 2014 to 2016 and they're all quite similar and they're all about 50 megawatts in size.

The slide changes and we see an ariel image of two solar towers. The tower is surrounded by many rows of mirrors which are aiming beams of sunlight up toward the top of the tower. The title of the slide reads “Abengoa, Towers PS10 and PS20”.

[Chris] So, these are some of them. They're not all parabolic troughs, some of them are tower systems like this where the heliostat's direct sunlight up to the top of the tower where there's an absorber which then heats up a fluid that then goes away to a steam generator and turbine generator. So, these are the Abengoa ps10 and ps20 plants. Very early at around 10 megawatts to 20-megawatt sizes, so they were quite early systems. I've actually been there, I've been up the ps10 tower and believe me, you don't go up those towers until you've had a good look at where those mirrors are pointing because it gets somewhat hot up there. When we got up there everything was melted at the top as well, so yeah, the lift up the tower was a bit of an experience as well but that's another matter, I think things had got a bit askew in all the heat.

The slide changes and we see two images of the Gemasolar heliostat plant. One picture is an ariel view and the other is from the ground looking up. Beneath the images are a number of bullet points which read as follows:

[Chris] So, that's the Gemasolar plant near Seville and if you fly into Seville airport any time you might well see the light from the Gemasolar plant, it's quite close to the sea. I just think these things look very picturesque and certainly when they're lit up, they do, they look very picturesque.

The slide changes and we see three images. The first is a map of the northern region of Spain with dots over each area where there is a CSP Plant, making up four locations in total. The second two are images of heliostat towers from the ground. The title of the slide reads “CSP Plants in the Mena Region”.

[Chris] These here are in the MENA region; this is the Shams plant in Abu Dhabi. I'm very fortunate to have seen that one and that's quite an impressive plant as well. The biggest CSP in the world is now in Morocco and it's got a huge PV plant there as well. The slide changes and we see an image of a heliostat in South Africa. There are bullet points above the image which read as follows:

[Chris] That one is in South Africa, I haven't seen that one, I've been in South Africa, but I haven't actually seen that plant.

The slide changes and we see an ariel shot of a massive solar energy facility in the middle of the desert. There are three heliostat towers, and each is surrounded by several kilometres of mirrors. The title of the slide reads “392 MW Ivanpah Solar Facility”. Beneath the image is a list of bullet points which read as follows:

[Chris] That's the Ivanpah plant in California. I've been there but we weren't allowed to go inside, we just had to look at it from the outside. That's the plant where there's a lot of bad publicity about it, about birds being caught in the sunlight and birds being killed. What they do is they defocus them when they don't need the heat, so they defocus the light and focus it somewhere else other than on the tower and they tend to focus it somewhere in the air and if birds fly through that they'll be vaporized. So, they've stopped doing that now, they don't do that anymore, but the story persists, so there you go, bad publicity is difficult to change people's perceptions. If I talk to people about this plant usually, they'll say "oh, that's the one that kills all the birds" and I go "no! It used to."

The slide changes and we see two images. The first shows an ariel view of a thermal storage unit and the second shows a 3D render of the same facility. The slide’s title reads “Molten Salts Thermal Storage” and there are some bullet points above them which read as follows:

[Chris] So, that's DSP, and you can say "well, so what? PV is better, isn't it? PV is cheaper. “So, if PV is cheaper, then what's the advantage? Why on earth would be doing this if PV is so much cheaper? It's about storage, it's much easier and cheaper to store heat than it is to store electricity. I know you can pump water up hills, and you can do very clever things to store electrical power and convert it to something else but it's so easy to store heat. When you've generated heat from the sun and you're heating up a fluid, you can then store it in these big tanks which is what they're doing here, and all those CSP plants or most of those CSP plants I've shown you operate 24 hours a day as well because they generate an excess of heat during the day which they then store in these big tanks and then at night they extract the heat through heat exchangers from these big heat stores and generate steam to run the turbine and generate electricity.

At night these plants operate aroundthe clock, you can't do that with PV. It says here that this is storing about 1 gigawatt-hour of energy. You try and store 1 gigawatt-hour in a battery, good luck, it's not easy but it's very easy to store it as heat so that's a big advantage that these things have. One day, somebody will invent really cheap, simple and cost-effective electrical storage, large-scale grid-level electrical storage and then I'll be able to go home. But, until then, we still have these which have a big advantage.

The slide changes and we see a diagram showing the balance needed when storing thermal energy. The title of the slide reads “CAISO Duck Curve”.

[Chris] So, this is just showing the same thing. PV is very good at filling in this time, from midnight to midnight if you like and during the day. PV is really good; PV will generate electricity for you but what do you do during the night? What do you do here during this peak time between six and nine o'clock when everybody goes home and switches everything on? How does PV help you there?

There are plans for some CSP plants to not generate at all during the day and just store their heat and run at night and just do it that way because of the heat storage. As it says here, the cost of storing heat compared to electricity is an order of magnitude cheaper times 10.

The slide changes and we see a bar chart showing a steady increase in the number of CSP facilities being built between 1985 and 2018. The slide’s title reads “Current CSP installations” and to the left of the chart there is a sentence which reads “Until 2015, only Spain and the USA contributed significantly to the STE Fleet”

[Chris] Anyway, to move on, there are now many more plants that are being built. This was all quite new in 2008, this is when all the Spanish plants were built around 2008 to 2011 and as you can see, more and more countries are now building these plants, so its very much technology of its time.

The slide changes and we see a heat graph showing structural stress on the supports of a mirror. The areas with the most support are shown in red and the areas with less support are shown in blue.

Above the graph, the title reads “Concentrating Solar Power(CSP): Characterization of CSPCollector Surfaces–Ronda Mirror Segment”. Beneath this, we see two bullet points which read as follows:

[Chris] So, what can we do? We're in the UK so how on earth can we contribute to that? Well, as I say, we can measure the shapes of these mirrors.

Here's a result of some photogrammetry where we measure the shape of the errors if you like in this mirror and we found there were some errors, but these are quite small, these are about 0.3 at the most, 0.3 of a millimetre which doesn't really matter, to be honest, this is not precision engineering so that mirror was actually okay. That's a mirror that went into the plant in Egypt by the way.

The slide changes and we see four images appear. The first shows the construction of a large, concaved mirror segment. The two above it show the various stages of instillation, with two men lifting it onto a platform which can support its weight. The final image shows all of the mirror segments installed and shows the length of the structure which disappears into the horizon. The title of the slide reads “Characterization of CSP collector Surfaces–Mirror segment (ENEA).

[Chris] Here we are in Italy, doing some photogrammetry on the test line in Italy, not the sunniest of days as you can see. So, we can do this anywhere now in the world, we can do these measurements and specifically measure the shape of the mirrors to see if they're reflecting the rays to the right place on the absorbers.

The slide changes and we see images of much larger mirrors being installed in the middle of a desert. This time, a crane platform is required for workers to access the top of the mirrors and we can see an image of Chris standing beneath one of the mirrors which towers over him, about 20 feet in the air. The title reads “Characterization of CSP Collector Surfaces–Mirror Segment (ENEA)”

[Chris] Here we are in Spain doing a similar thing. I may not be very tall, but you can see how big those mirrors are, about seven meters high, 7.5 I think. They are huge, believe me.

Again, if you stand there you make sure you know where the sun is before you decide to stand there because very often, we're doing work on these mirrors and you smell burning and you realize your trousers are on fire, that's been known to happen.

The slide changes and we see two images appear. The first image shows a similar mirror installation in the middle of another desert. The second image shows Chris standing with a man dressed in a traditional Saudi Arabian Thawb robe and is wearing a ghutra on his head while Chris wears a shirt and tie which appears to be unsuitable to wear in the heat of the sun.

To the right of these images is a line graph which shows several lines starting from the top of the page and overlapping in the middle before spreading out to cover most of the bottom of the graph. The graph is titled “Parabolic Trough Ray Trace(mm)” and the title of the slide reads “Characterization of CSP Collector Surfaces–KAU CEDT”

[Chris] Here we are in Saudi Arabia doing the same thing, this is in Jeddah on the top of the desalination plant at the KAU University in Jeddah. Being English, I've got my tie on, I have taken my suit off but I'm still wearing my tie and it's about 45 degrees or something like that and we're in the shade. My friend there from the university came out for the photograph and quickly went back downstairs and said, "I'll leave it to you then to measure the mirrors" and left me up there on my own *laughs*.

The slide changes and we see an image of a much smaller CSP facility which is at scale size. A similar graph to the one before is seen, but this one shows a noticeably less accurate result, with the mirrors appearing to be out of alignment. The slide’s title reads “Characterization of CSP Collector Surfaces–COMSATS (Islamabad)”

[Chris] This is in Pakistan on the other end of the scale really. This is a solar cooker, so it's what we call a linear Fresnel, it reflects sunlight from these mirror strips onto an absorber above which is then used to heat oil which goes to a heat exchanger for a solar cooker.

The interesting thing about this one is that it cost nothing, the glass was found on a rubbish tip, so you've got bits of glass off rubbish tips, the metal was metal that was lying around, and it was just done virtually for no cost whatsoever. It's a very cheap solar cooker and we tested it out and as you can see, it wasn't very good, it Wasnt very well aligned, and it hasn't got a very good focus up there as you can see.

When I phoned up my friend about a year later and asked how it was performing and he said "oh, somebody stole it." You think you've got everything under control and then somebody walks off with your solar cooker, and there you go. So, we lost that one.

The slide changes and we see another scale facility, this time it is a scaled-down heliostat with several small mirrors pointing towards a small tower. The mirrors themselves have a strange circular pattern on them which is different to the larger heliostats which simply have large, concaved mirrors. A similar graph to the one in the previous slide appears which also shows that this system is out of alignment by a considerable margin.

[Chris] This is also in Saudi Arabia, which is a very odd kind of design with these mini heliostats pointing up to the mini-tower. So, Harradine would be interested in this because he works on modular mini-towers. This is at KSU, and this wasn't very well aligned either, as you can see it's not very well aligned, you can see that it doesn't point at this, it should all point at a single point, but it doesn't. So, we told them that and they've redesigned it and I need to go out there again sometime to retest it and see how it's working now.

The slide changes and we see two images. The first shows two women working on a full-sized mirror and the second shows a heliostat facility in the middle of a desert.

[Chris] Okay, I should just say a word for my friends in Spain because when we come to do outdoor work we have to go outside the UK, and I like to say that my outdoor lab is in southern Spain which it kind of is but that only because my friends in Spain let me go there and use their facilities for nothing. So, I would just like to say thank you to my pals in Spain.

They work at this big research centre, a big government research centre in southern Spain where we have test lines, test towers, troughs, heliostats and all sorts of things. I've got materials out there under tests at the moment and it's in the Tabernas desert, if you've ever been to southern Spain, it's near Almeria which is not too far from Malaga. There’s one desert in Europe and that's it, it's classified as a desert and that's where I tend to go for outdoor experiments.

The slide changes and we see several images of people working on various tasks on large mirrors. Two of the images show Chris standing with several people in the shade of the large mirrors.

[Chris] Here we are with my pals from Spain and Germany, we're doing some work there comparing our different reflectometers to measure the reflectance of mirrors, we've got three different instruments and we're trying them out there. You can see that we've taken every opportunity to shelter under the mirrors, that was a scorching hot day.

The slide changes and we see an image of a truck with various brushes and spray nozzles mounted to robotic arms on the back which scrubs the surfaces of several, full-sized mirrors. To the right, we see a closer image of one of the robotic arms on a table in a lab alongside images of the various brushes that can be mounted to it. The slide is titled “Contact cleaning–Simulation”.

[Chris] We also got involved in the cleaning of mirrors as well. These mirrors are all covered in dust all the time, that's one of the disadvantages. So, we got involved with cleaning these mirrors and how to clean them more efficiently, at the moment they use these things, these brushes and water, and of course, what haven't you got much of in a desert environment? Water is a precious resource, and they use brushes and water so we've always been working on ways in which we could use less water and do more efficient brushing and cleaning of the mirrors and we can simulate that process in the lab using a robot with brushes on the end and we can try different sorts of brushes, different amounts of water and we can also try different sand and dust to see what is the most efficient way of cleaning these mirrors.

The slide changes and we see an image of a large spray nozzle cleaning a full-sized mirror. To the right of the slide, we see two more images, the first shows a lab which is testing various spray nozzles on a scaled-down mirror surface and the second shows various different grains of sand of varying colours on a countertop, each contained within a glass vial. The slide is titled “Non-contact Cleaning Simulation”

[Chris] Sometimes, they don't use brushes, they just use jet washers which are easy to simulate, we've got a jet washer and we can simulate that in the lab too, but we always use the real sand and dust from the environment. So, I have become a bit of a collector of sand and dust and if anybody ever goes on holiday anywhere and you find some interesting sand or dust can you bring me some back? Because I do collect sand and dust for people's amusement... Because it's different you know, there's
red dust or sand from red sandstone from Arizona, that's from Almeria, it's volcanic and almost black sand... And then these are more usual.

The slide changes and we see two bar graphs appear. The first shows the effectiveness of using water and not using water when cleaning and the amount of reflectance that each method produces. The second, graph shows the reflectance of a mirror after cleaning with various hardnesses of brushes. The title of the slide reads “Contact Cleaning of Polymer Film Reflectors” and a paragraph is seen below the graph which reads:

“Measured on Condor portable reflectometer at Cranfield (650nm). Various grains of sand are included in the measurements: Fanuc robot cleaning tests. The graph shows the influence of both water and brush hardness on the specular reflectance drop of the polymer film reflector samples after 400 cycles, which approximately corresponds to 7.6 years of operation in a CSP plant (assuming typical washing cycles of two weeks).”

[Chris] We looked at different types of reflectors, all the reflectors I've shown you and all those mirrors are all thick glass, very heavy and expensive thick glass mirrors, because otherwise in that heat, they would distort. They're back silvered as well, you can't front silver them because that would just get blasted by sand, so they're all back silvered so the light has to go through the mirror and then back up the silver and back out again.

So, we looked at other things, other ways. We looked at polymers, composites and all sorts of other reflecting materials as well and that's quite an interesting ongoing experimental route for us at the moment, a lot of work on that. So, we were looking at how we could clean these polymer films without damaging them and without scratching them with the sand and dust.

I also got involved with trying to find ways to prevent the...trying to find ways to prevent the mirrors from getting sand and dust on them in the first place, so we came up with these ideas for dust barriers around the plants, aerodynamically shaped barriers that would make the dust and sand behave in certain ways; make it go up in the air or maybe stop it dead at the barrier, so we came up with all sorts of ways of doing that. Porous barriers were the best at about 50%, with a barrier roughly the same height as the parabolic trough which seemed to work the best.

This was a European project, we did CFD modelling, first of all, to see which would be the best idea...

The slide changes and we see various images of different types of model barriers being tested in a small-scale wind tunnel, where water vapour is released to show the path that the air current takes around the barrier. The title of the slide reads “Dust Barriers: Wind Tunnel Validation–Effect of Barrier Shape and Porosity”

[Chris] then we went to a wind tunnel which we built ourselves, you can see that it's made of wood. We built the wind tunnel, and we made some barriers by 3D printing some model barriers to go into the wind tunnel. So, we went from theory to wind tunnels to the real world.

The slide changes and we see various images detailing the construction of a full-sized barrier. One of the barriers is metal while another is simply a desert bush which has been grown in a specific area. The slide’s title reads “Dust Barriers: Performance Evaluation”. Beneath this, we see a number of bullet points which read as follows:

[Chris] We built those then outside in Almeria, the PSA as it's called (Plataforma Solar de Almeria) and we tested them out there to see which shape performs best. The next step after that was to build the full height ones at a real plant which is what we're trying to do, we also compared them with a real barrier, a bush, but ours were better, this was awful. Bits came off this bush in the wind so we're better off with the artificial barriers.

The slide changes and we see a new slide titled “Anti-Soiling Coatings” which contains a list of bullet points that read as follows:

[Chris] Anti-soiling coatings as well were something we've looked at. Again, you might think "how do you stop the mirrors from getting dirty?" You could use anti-soiling coatings, so these are copolymer type materials, so it's two polymers, one sticks to the surface and the second bond sticks up and it's got a negative charge on the end, most dust particles are negatively charged so it repels the dust and that's the idea.

So, we worked with this company called Cameilik on those, but I found out recently that Camilik had gone bust, which tells you how effective that was. Unfortunately, it didn't work very well, but it's something I think we ought to be pursuing in the future and things like anti-soiling coatings and dust barriers do have applicability in the UK. I was at Breedon Hope cement works the other day and while we were trying to stop dust from getting into the plant, they might be wanting to stop dust from getting out into the community. So, there are opportunities there to do that even locally here in Derbyshire.

The Slide changes and we see a massive building with a huge, curved mirror built into the side of it which is several meters tall. Adjacent to this building is a heliostat tower which faces toward the giant mirror. The slide’s title reads “1MW Big Solar Furnace–Odeillo (France)–Builtin 1968.

[Chris] I'll probably skip one or two of these, but I'll finish with the solar furnace because I've been talking about power generation. But there are other things you can do with concentrating solar; this is not really a concentrating solar plant but it's such an interesting piece of equipment. This is the big solar furnace built in Adeo in the south of France, not far from Perpignan, it's about an hour's drive from Perpignan. It's just got heliostats that direct sunlight onto this huge parabolic reflector that is made of many segments that then reflect light to a point and by the time you've done all of that, you've got something that's well over 3000 degrees Celsius. So, really high-temperature research is what this is used for.

So, I'm using it as an example of a nice parabolic solar reflector, but it's actually used for high-temperature materials research, temperatures that you normally won't find on earth but the sun. So, it has other uses but it's such a fun place to visit if you get a chance to go there, it's really interesting and it's got a number of floors and by the time I was there the lift had broken, so they made us walk all the way to the top which was a good exercise I can tell you *laughs*. Much better coming down. But that's a solar furnace. You may hear about that at some point as it makes the news sometimes when there's some new discovery there where the material behaves very unusually perhaps at a very high temperature.

The slide changes and we see several images of low-tech solar cookers and heliostats being deployed in impoverished regions as an alternative way to heat food and water. To the right, we see a woman standing in a sunny, English field with a makeshift solar cooker, made from a reflective material that has been bent into a concaved shape. In the middle of this cooker, we can see a chicken breast being cooked by the sun. The title reads “Low-Cost Solar Cooker Design–Prototype”

[Chris] A couple more examples here, that's the Pakistan solar cooker again, the other two are box cookers. This cooker here was a project that we did at Cranfield where Miriam (who was a student at the time doing her master's course) got an award for this one, not for the design of the cooker to be fair because you can get that off the internet but we came up with a way of trying to justify how a sub-Saharan African country could make a million of these cookers and deploy them in their countries at almost negligible costs. It's a frightening fact that over a million people die every year in sub-Saharan Africa from inefficient kerosene cookers and overhead is blistering sunshine, so we made use of it just to prove the concept. Miriam cooked a chicken dinner at Cranfield, it was a nice day as you can see from what she's wearing, it's a sunny and hot day so she made a chicken dinner and we ate it and we all survived, so the experiment was successful! *Laughs*

The slide changes and we see two images. The first image shows an indoor facility that is using large mirrors to heat and purify water and the second shows several people gathered around a small CSP facility on a rooftop. The slide is titled “British Council Funded Projects: Solar for Biofuels and Water Provision”

[Chris] Here are some other things you can do with concentrating solar; this is very interesting work that was done with a company... I can't remember their names, but it was a UK small start-up company, and they were looking at extracting biofuels from microalgae, so microalgae which you can farm. If you put that aloe with water into a tube and you heat it up to around about 320 Celsius.

This was actually done here in India at Kota University in Rajasthan we did the experiment where you heat it up then reactions take place and out the other end comes something a bit like palm oil plus something that you can use as fish food, which is big industry fish food, so you can feed it to fish. There are some other unwanted by-products like some gases as well but nevertheless, that has really taken off, a lot of people are very interested in this.

A new slide appears which shows two images. The first shows an illustration of a potential design for a desalination device which has two, large Fresnel lenses aimed toward the collection of metal tubes and boxes. The second image shows people in suits standing around a model for a large, domed facility. The slide’s title reads “Desalination: Evaporation and Distillation”.

[Chris] And, this is just an example of a very small desalination unit for water purification, boiling sea water basically and then distilling it again until it's pure h2o. This is a British Council project which we haven't made yet, but we've designed it and published it in conferences, but we haven't actually built it yet and it was to come up with a small desalination unit or water purification unit for refugee camps in disaster zones that could be dropped in containers into those areas, basically trying to save someone's life. So, it's not designed as a highly durable long-life product, its made from plastic lenses to concentrate sunlight onto an absorber, and you then store that heat and when you need to use the heat, seawater is sprayed onto the hot pipes, water evaporates and then gets blown by a fan into a condenser and condenses out as pure h2o.

We designed that but we haven't actually built it yet, so we'll do that small-scale. On the other end of the coin is the work we've been doing with solar water PLC. If you google solar water and look at their website solar water is a massive business now, building a huge desalination plant in Saudi Arabia at Neom and also planning to build one in Jordan. That started out as a student project at Cranfield, it started as a few students working on it and building a little model, evaporating seawater and distilling it and condensing it.

It's a good example I think of how universities help, it's what you dream of in a way, that you can start out with a student project that will grow into a multi-million-pound business and make the university famous and all the rest. Doesn't happen very often but you have to work with a hundred companies at least to get one that does that but it's a nice story in thinking about how the universities can play that role.

The slide changes and we see a diagram of a heat storage device which shows a Fresnelcollector device transferring heat into storage tanks which can then be sent to residential buildings. The title of the slide reads “Seasonal Heat Storage”.

[Chris] And finally, this is heat storage. Heat storage of course has...I talked about grid-level storage, I talked about gigawatt-hours of storage in those hot molten salt tanks but storage generally in the UK, we can store heat in the UK too and I don't know why we're not doing more of this. Obviously, all the heat comes in the summer and we want to heat our homes in the winter so it makes sense to store that heat and there are a number of ways you can do that.

One of the most interesting is if you've seen the Grand Designs program, we worked with a guy in Milton Keynes who built his own house and buried it under the ground open to the sun. You put the earth on top of it and the earth is separated using polythene sheeting under the ground and those are the heat stores. I spoke to him recently having just got through this last winter and he had had no heating on all winter, his house was kept warm by the earth. He's got pipes everywhere and he piped lots of heat in in the summer, so it was ready to pump back in the winter, so I'm not suggesting that it was easy or cheap to do but he reckons it costs less to build than a normal house, so I think I'll challenge him on that at some point, but it did make it on the Grand Designs programme.

So obviously, I think heat storage in particular seasonal heat storage has a role to play in the UK too and I am talking to a number of councils around Derbyshire on these kinds of things. One of the other types of heat storage and one of the most interesting is magnesium sulphate heptahydrate which is Epsom salts you can buy in the chemist. I probably shouldn't tell you this as I'll get into trouble with health and safety but if you take up Epsom salts and bake them in your oven, basically, you're driving off those water molecules and you then keep it in a nice dry airtight environment and then a few months later you go back and put those dried Epsom salts in a beaker and pour cold water on them, they will absorb the water and the heat will come out and that water will go up to 60 or 70 degrees Celsius. There you are, you've got seasonal heat storage.

So, that brings us full circle. My CSP work continues with my team and Sahara Dean is here to represent them today so that work continues. My work on renewable energy at Cranfield broadened out from solar to renewable energy and now I find myself in Derby working on anything to do with renewable energy, but even broader than that now, now we're looking at how we can help the East Midlands, Derbyshire, B2N, Derby city or whoever. We're working with all of these people at the moment in trying to help them on their journey to net-zero and that includes (as well as Derby of course) all the people working on climate change and on carbon sinks and any other way of extracting carbon from the atmosphere as well.

I feel very privileged to have worked on not just looking at ways to save the world and find new worlds but also now in an opportunity to perhaps spread some of this knowledge out more locally. I still enjoy my international trips and I enjoy my international work but it's nice to come home back to the UK now and have the opportunity to share some of these ideas with people in Derbyshire.

As I said to you right at the start, I didn't plan any of this, it kind of happened to me but I'm very glad that it did and I'm very happy to be here today and to take you through some of these ideas. Thank you very much for listening. *Applause*


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