Scheffler Dish for cooking and power in developing countries
Invented by Wolfgang over 25 years ago 1000s of Scheffler dishes are now installed at 100s of locations around the world. Wolfgang Scheffler has made his dish designs and associated intellectual property available for free to create a solar world.
Originally Broadcast on the 5th of April, 2009
Visit Heike and Wolfgang at Solar Brueke for more information.
Beyond Zero interviews Wolfgang Scheffler
Transcript
Mark Ogge: We're really excited today because we've got Wolfgang Scheffler who is the Austrian-born inventor of the Scheffler reflector which is a concentrated solar power dish developed to provide clean, accessible, low cost solar energy, aimed particularly at an alternative to wood-fired cooking in developing countries. And this is to address the enormous problems associated with fuel scarcity and deforestation when people have to go out every day and find firewood to do their cooking, and also the pollution issues as well. So it's a really exciting thing. Currently there are over 2,000 Scheffler dishes around the world providing…and they're in installations of various sizes, and some of them are providing up to 18,000 meals a day at a single installation, and it's really interesting to know that Wolfgang provides this technology for free to others to use.
David Hall: I believe we've got him online at the moment. Hello Wolfgang.
Wolfgang Scheffler: Hello.
David: Welcome to the program.
Eva Migdal: Welcome to Australia.
Wolfgang: Thank you. Very far away!
Eva: Is this the first time that you've been speaking on Australian radio?
Wolfgang: Yes, yes, this is the first time definitely.
Mark: Welcome Wolfgang. I was hoping you could tell us a little bit about yourself and how you came to develop what's now called the Scheffler reflector.
Wolfgang: Well, I grew up in Austria and later studied physics in Germany, and I was always a little bit of a social minded person, so I wanted to use all the knowledge which I gained in physics for some useful application which will be useful for the world as such. So I was always thinking on these lines, to do something socially important. And then of course we hear about firewood crisis in Africa and all these things, and then with a friend of mine together we had the idea to build greenhouses in the desert, that was in '82 or '81.
Eva: What do you mean by 'greenhouses in the desert'?
Wolfgang: To make land liveable where otherwise you cannot live, and for that you need water and sunshine, and the water should not go away when the plants grow, and so the idea was to make a glass housing where the water is being recycled inside. And you could even use saline water to do so, and at night-time the water would condense on the glass.
David: Was that successful, Wolfgang?
Wolfgang: No, no, that was just the initial idea, how it came to the solar reflector. Because the glass I wanted to melt locally using solar energy.
David: Was this in Kenya?
Wolfgang: No, at that time I was sitting in Germany and studying physics. You know, you sit there and then you have your ideas, and then this idea pops up and then you stick to it, and then I went into glass manufacturing, what is necessary. I realised it's about 1,500 degrees, and a glass oven is very heavy, and if I want to do it with solar I'd need a concentrator which is focusing a lot of light to a fixed point because I cannot move that glass stove, you know?
Eva: So initially this was because you were trying to work with glass, it wasn't the original plan to come up with the solar reflector.
Wolfgang: It was not for cooking initially, but using renewable energy for a benefit somewhere, to make something which can be reproduced without input from outside a lot, to make people independent, that is the idea.
Eva: It's very interesting because we see that this is actually open-source technology that you've developed, and I'm just wondering, because most people would have been putting their copyright onto that and manufacturing it in a way that they could actually benefit financially from it, so I'm very interested in how you came to choose that as a pathway.
Wolfgang: You see, what you think socially then you don't think in terms of money because you do things which are necessary to be done for the benefit of yourself and everybody in that way. And then the concept of money which we have, the whole concept of our economy is not that we share things. We try to be better and have more than others, and that is completely opposite to a world where we take care of each other. So I felt I cannot do that way, I have to deal with the human beings directly, I cannot first be afraid that I will not have enough.
Eva: So you were coming from a very strong philosophical understanding of how to make the world work better.
Wolfgang: Yes, it would seem so.
Eva: So what was the next step in the process of the greenhouses that obviously didn't end up as the endpoint?
Wolfgang: Yes, because I thought that I was not able to make the reflector so good that it will be having that 1,500 degrees and big enough. And then, you know, it's a fancy idea more or less, but then because of the firewood crisis in Africa and so on, I felt it was much more closer to use that type of reflector for cooking.
Eva: And everyone needs to eat.
Wolfgang: Yes, exactly, and a reflector with a fixed focus point is also much more comfortable for cooking. You know, all other solar reflectors you have to move the reflector and to focus and shift everything along with the sun as it moves over the sky, and with this design you can have very comfortable cooking. We humans, we do things which are comfortable, if it's too cumbersome we leave it.
Eva: I think there's been research that shows the number one reason for sustainable action is convenience. So if it's not convenient, people don't do it.
Wolfgang: Yes, exactly, so I felt if I can make it convenient it will succeed. Of course it was much more complicated also than the other simple solar cookers.
David: So the original ones, Wolfgang, were quite small, they were about two metres squared, weren't they. They had the fixed focal point which was actually directed onto the hotplate or the pot. How many people did those early ones cook for?
Wolfgang: The first one I built that was already in Kenya, that cooked for five people, it was a mission station so they used it there. But immediately they became bigger because Fathers there, they asked, 'Look, we have a boarding school, we have to cook for 150 people. This design of yours, can it be made bigger?' And then that way it started to grow.
David: Right. Over time, did the design change much or was it just a matter of making it bigger or were there very big changes in the actual design?
Wolfgang: The basic structure reflectors that…the surface is not the same for every day because the sun angle changes every day from summer to winter, as we know. The reflector, in order to have a fixed focal point, needs a different shape for every day. So that shape-changing mechanism, that was refined over the years, like up to 1990. After that it's quite the same design.
Eva: So you mean the reflector actually changes its shape?
Wolfgang: Yes, exactly, like when you take an orange peel, something like a flexible bowl from rubber, and if you flex it one way you can change the shape of that thing.
Eva: What is it made of that it's flexible?
Wolfgang: Basically the flexibility comes from the backbone, that is a very light frame of steel which looks elliptic, and some circular things which are in parallel mounted to that, and that is the flexible structure. Onto that they come fixed the glass pieces but they don't flex, it is just a piece of glass and they are small. So, many small pieces on a flexible structure.
Eva: So the glasses become like mirrors?
Wolfgang: Yes, the glasses, they are the mirrors, right.
David: Wolfgang, part of the success of this in its applications is that they're relatively inexpensive and they're made from available materials, they can be fixed by local people. I know that the fixed focal point is crucial in making it a nice simple design that can be used in all these different situations. Could you talk a bit more about how the simplicity of the design and the simple materials have…how you worked all that out?
Wolfgang: The design as such is not so simple, it required a lot of calculation and a lot of care in manufacturing, but the materials are only the materials which you find locally, like there are steel bars, square tubes of steel like when you make furniture you use them, and some pipes. So that can be found everywhere, that's why the whole development actually I did in Kenya together with people in Kenya in rural workshops, and then every step of the design I adapted to what I could do there, like the welding procedures, how we joined things, which way we cut. So all these procedures are designed in Kenya together with Kenyan people, so that way the making is possible everywhere. But still you need a lot of understanding if you want to make it. If you want to use it, it's simple.
Eva: How long did it take you? How long were you in Kenya for to develop this process?
Wolfgang: I started to go to Kenya in 1983 and I remained…every year I went for about three, four months, sometimes even ten months, until '97. In total it was something like five years I spent.
Eva: And was this part of your day job, was this part of research that you were doing at university or was it just part of your own private plan?
Wolfgang: That was all privately organised. When I finished my masters degree in physics I immediately left university because I felt I have to be out in the field in order to make this proceed. From universities things go very slowly and the researchers are very much concerned with their own things, you know, with their papers and getting the money for the research and all this, so a lot of time goes into that.
Eva: It becomes a distraction.
Wolfgang: Yes, exactly.
Mark: It's often frustrating when we see solar technology in Australia that spends ages and ages in the research and development stage, so it's quite inspiring that you got out there and actually learnt as you were making it, which actually got the thing up and running relatively quickly.
Wolfgang: Yes, I always felt it has to go out and you have to be in the field. In Australia you do a lot of very nice solar research I always keep reading, but they always ask, 'Where is it now?'
Mark: Yes, we ask the same question.
Eva: We'd be very interested in using you as a mentor though for those people locked away in their laboratories at the universities who want to take things further. Would you be interested in that?
Wolfgang: Pardon?
Eva: Would you be interested in mentoring those researchers that are stuck in the funding cycle, to take them under your wing and show them how to do stuff out in the field?
Wolfgang: I don't know. Well, we can get in contact. I don't know how to do it otherwise.
Eva: It's very interesting because if there were more people doing exactly what you are doing where you actually work with the communities that are going to use the end product and get their inputs and have that whole practical hands-on approach, the outcomes are clearly very, very exciting.
Wolfgang: Yes, but the problem is also it's not only that you're an institution, the problem is that you think you need a constant flow of money if you want to do your work. I went away from that. I said if I live in Germany I cannot die of hunger at least, you know, and I'm working for people who die of hunger actually, you know? So I have to keep a proper relation between what I have and what the people have which I'm working for.
Eva: So you spend a lot of time obviously in third world countries with this work at the moment?
Wolfgang: Yes, right now I'm mostly in India when I'm doing this work, like three, four months every year I'm in India. Otherwise I'm at home in Germany.
Eva: And are you happy with how it's progressing in India? Is there a roll-out plan? Is there a way of getting this to grow faster than it is, or are you happy with how that's going? How do you feel about the uptake of it and the needs in the community for it? Is there a gap?
Wolfgang: Well, at the moment it's going faster and faster, so I'm happy. It was a long time when it was not moving very fast for so many reasons, but right now I feel that in India but also worldwide it picks up very much.
David: Wolfgang, I'm interested in the time of day that these ovens are effective. How does that work?
Wolfgang: They are effective whenever the sun shines, independent of time of day or temperature or season. So that means maybe one, two hours after sunrise, when the sun is strong, they work, and they work until the sun gets weak because it sets in the mist or whatever.
Mark: I noticed you also had a bit of a storage…like a 300-kilogram iron drum it looked like that stored energy that could be used after dark. How effective is that?
Wolfgang: We did some samples. We did a small iron which we used in Portugal in some installations for many years. Because it's small, 50 kilograms of iron is just a few litres, you know, it's like six litres of iron, so it's quite small, so it still cools down a lot. Like when you have 450 degrees in the evening, in the morning you have 300 degrees. If you increase the mass of iron, like what you talked about, like 300, 400 kilograms, then that drop is only 50 degrees overnight. But then the next day you still have a lot of energy to cook and to use.
Eva: And when you said that it's independent of whether there's clouds you can still cook, is that what you're saying?
Wolfgang: Well, if you have the storage you can cook when the clouds are there but otherwise you can cook only when you have the direct sunshine of course.
Eva: So you need direct sunshine?
Wolfgang: Direct sunshine, yes.
Mark: Wolfgang, we spoke to Deepak Gadhia a few weeks ago and he's somebody who is taking your technology and has commercialised it on a large scale. And he was also talking about, with the larger installations, using a solar collector that produced steam. Could you tell us a little bit about using your technology for steam cooking?
Wolfgang: When the communities become larger, more than a few hundred people, then it becomes inefficient to use the many individual reflectors with individual cooking places, and then we developed a system where actually you have a huge number, up to 100 dishes, and in the focus of each dish there is a small drum where water boils, and that is connected to a very large drum which contains more water, and that water is heated up to above boiling point. The temperature is then about from 120 degrees to 180 degrees. So immediately when you open a valve above that water it will flash into steam and then that steam is going in one pipe and that is going to the kitchen, and from there it is distributed again to the cooking vessel. So the cooking actually is done with steam and heat transport is also done with steam, and the generation of the steam is with the reflector. And that works very effectively for large installations.
David: Okay. And the reason that it was inefficient to use the style you had before and the sun's energy was directed into that hole straight onto the cooking pot or plate, the reason is that because of the gap you needed…because the reflectors are so big you'd end up with a really enormous kitchen presumably if you used that original design.
Wolfgang: Exactly, then you have too many small vessels and the cook is not happy if they have to tend to 50 vessels of 30 litres each, he wants one vessel or ten vessels with 300 litres.
Eva: You can tell that you've been working on the ground with the cooks! What's the cost of it? I was reading all your stuff and looking at the fantastic slide shows where you show all the examples of what's being done, and we will give that website out soon. What is the cost of it? I saw that there was a two-metre Scheffler dish for sale for $2,500 Swiss francs, I was wondering if that was a good price. How much does it cost? Because in Australia we don't have any Scheffler dishes yet, and I just want to know, is it a viable economic option for us or do we actually make it ourselves to make it a viable option?
Wolfgang: You have to differentiate two things, like if you build it in India or in Kenya the costs are much lower than when you built it like in Switzerland because the cost of the work is the major difference. If you built it in India and Kenya, working costs and material costs are about 50/50, while in Switzerland working is 90% or 95% and materials are 5%. So in India you can build a ten square metre Scheffler reflector for something like 1,000 to 2,000 euros, depending on who is doing it. And in Switzerland, for double the price you can just build a two square metre.
Eva: So what's the equivalent amount of energy that's going to come out of a ten square metre dish?
Wolfgang: That is about 2,000 to 3,000 watts, and that is for about eight hours in the day, so you get roughly 22 kilowatt hours.
Eva: That sounds cheap. Unfortunately Matthew is not here because Matthew would be making all sorts of equations and explaining how good it is, because I know how excited he was to find you. He's been looking for you, Wolfgang, for a few months now because as a person who really has his head around all the different options around the world he was very excited by the capacity of your dishes. But even to me it sounds cheap.
Wolfgang: Yes, actually in India when they built these dishes in industrials places, for industrial steam, like for a laundry, they have a payback period of 1.7 years, that's with a 50% grant from the government, and without that it would be just 3.4 years economic payback time.
Eva: That's amazing.
Mark: That's really amazing. Are there any examples of it in…are they actually using Scheffler dishes in Western Europe at all?
Wolfgang: Not very much. We focus very much on developing countries because we feel in the western countries we already have enough, we are not very intelligent about using what we have, we have enough.
David: Wolfgang, just a little bit of insight in terms of the longevity of these, have you got some idea of how long they last and whether there's some sort of damage that you've found you have to deal with?
Wolfgang: The structure lasts very long. Like every steel structure you need regular painting if it's not galvanised. In Europe we use normally aluminium frames for these two square metre reflectors so there is no corrosion on that. The mirrored surface, if it is from glass, it lasts also very long. You need regular cleaning with water. The backside of the glass, the mirrors, have to be properly protected, if not…you maybe know that from your bathroom mirror, that from the edges the silver is affected by humidity. So that has to be protected, then it can easily last for 20 years and longer.
David: What about the tracking of the dish? It's a clockwork system, isn't it?
Wolfgang: There are different systems. I started with a clockwork system which gives me a lot of headaches until it is somehow working properly, and even to use it, it still gives a headache from time to time because the mechanics are not so much around. So we also developed a tracking system with a small electric motor and timer. So now it seems that more and more we'll be switching to some small electronic devices which even cost less then the clockwork.
David: I suppose with developments in that kind of computer software, that would be an increasingly inexpensive option.
Wolfgang: Even now it's quite inexpensive. Only as myself, I didn't know how to make these things, you know? Mechanically I was quite well understanding how things work and I studied for a long time how clockwork works and then made it, but you have to be very precise with the clockwork. And only two or three years ago, a friend of ours, he taught us how to make electronic circuits, so from then on we are more familiar and comfortable with electronic circuits.
Mark: Great. I suppose from our point of view we're always thinking about the kinds of solutions we can use in Australia to reduce our emissions and transition towards a zero carbon kind of future. In terms of industrial steam cleaning, even restaurants, do you think…we were asking you before about the costs in western countries and you were explaining that. Do you think this is a technology that will remain predominantly used in developing countries, or can you see applications for this particular technology in a place like Australia where we do have large industrial kitchens and cleaning and industrial steam and that sort of stuff?
Wolfgang: In the industrialised countries we have the big advantage then if we put our mind on something we can do it, we have everything, we have technology, we have machines. So once we put our mind, then it's possible. Like photovoltaics in Germany, we decided to have this feed-in law, giving a big market to photovoltaics, and you see how it was growing in Germany because we said we want it. And then the economic question we'll also solve. Same with cars; we want a car, that's why we pay the money for the car, even for the most expensive.
Eva: And the Indian government is supporting your dish, from the sounds of it.
Wolfgang: Yes, for many years now they have a 50% subsidy for the dishes.
Eva: Specifically for your dishes?
Wolfgang: So many solar applications they support. There's especially a ministry even for non-conventional and renewable energy.
Eva: Can the Scheffler reflector have any other applications apart from steam? Is steam the only way that it can concentrate the energy?
Wolfgang: No. Basically the Scheffler reflector produces heat, and with heat you can do so many things in your life, you can also do cooling and other things, so direct application of heat will be also something which will be useful in future. Like in Mexico people talk about melting aluminium, for instance, in a foundry.
David: Really? You could use your collectors to produce aluminium?
Wolfgang: To melt it, like if you have scrap aluminium, to melt it and then cast it.
Eva: How high a temperature can it attain?
Wolfgang: The normal dish, the two square metre, ten square metre, they have a maximum temperature of 700 but that is not useful. A useful range is up to 300. Then we are working on improving the design to make the focus smaller and that make it also hotter. So, for instance, for the solar crematorium dish we have a design where the concentration is 640, reaching an operating temperature of 700 and maximum above 1,000.
Eva: It's not a very pleasant topic, but maybe you can tell us a little bit more about the crematorium dish.
Wolfgang: That's a pet project of Deepak Gadhia, and for the last ten years I think I and him were working on it, and now the design is more or less finished. We installed one, but it's not yet really in operation. The idea comes from the Indian side, but at the moment there's a bit of lack of enthusiasm to put it into operation and keep it running.
David: Why is that, Wolfgang?
Wolfgang: I don't know. People have so many projects at the same time, I think that is the main reason.
Eva: Where would you like to go next? Because obviously you're an innovator of the highest calibre. What are you working on at the moment, or where would you like to see yourself or your reflector moving towards?
Wolfgang: Well, I think the reflector is pretty much moving on its own by now, and there are quite a number of people who are promoting it in many parts of the world. So myself, I might stay more at home and work on some social issues, like industrial countries like us. I said before, we are not using the resources intelligently. So maybe work a bit on that side.
Eva: Anything specific that you're in, because we're very interested here at Beyond Zero of ways of changing things on all sorts of levels, and while we're speaking to you I'm sure that you would have a few interesting ideas that we might want to hear about.
Wolfgang: Basically it's how can we make better decisions in our society on all levels. At the moment we have our democratic system but it doesn't involve really people, it doesn't really involve common sense. Very often we are very angry with our politicians, the way they behave. So to improve that there's a system which a German professor developed and it involves average citizens which are drawn by random from everybody. So this I'm propagating here in Germany and even our village now will start that process, just to see what we can improve in our own village here.
Eva: And what's that system called?
Wolfgang: It's called Citizen Report with Planning Cell, and it's invented by Professor Dienel, and he was in Germany and he invented it in '73. He died two years ago and he was working in Wuppertal.
Eva: So this system is being applied to villages so that you can get a better cross-section of what people are thinking, so ordinary people are being involved in processes of change, is that what it is about?
Wolfgang: Ordinary people are involved in the process of planning, whatever you plan, whether it's city development, village development or a technical development like the energy supply for a country, or if it's how you should organise your health system, everywhere it's used.
Eva: So it's similar to what you experienced in Kenya, from the sounds of it.
Wolfgang: No, no, it's a very elaborate system, like just randomly choosing citizens, they come together for four days and elaborate in small groups of five always, and then they put down their opinions and then they vote on these opinions, and that way you get a very clear picture of what an average society would be able to do and how much it could change, and it can change a lot, that's a very interesting outcome of these things. People have a lot of common sense and in these groups they also develop a lot of sense for the common good.
Eva: And the common people have more common sense than the people running the country, as obviously happens here. And if you're upset over there, imagine if you were living here in Australia with our leadership. All this wasted sun and wind, every single day we're just wasting it.
Wolfgang: Yes, we are putting a lot of effort here in Germany with the little sun we have and we can make a lot of progress, and we always wonder why are these sunny countries not doing similar.
Mark: Yes, I think Australia has one of the best solar resources in the world, so obviously that's why we've become experts in burning coal.
Wolfgang: Yes, exactly, so we have no sun so we've become experts in using the sun.
Mark: Yes, I was just wondering also…I was really interested by something you said before when I was asking you about the potential…I suppose the economies of your reflector, and you said that in a way the economics of it isn't the point, it's how you decide you'll source your energy. And in Australia I think the debate on climate change often gets turned into…the line you hear again and again is, 'Oh, it's too expensive, it's too hard to implement the solutions that…,' because we know we have solutions like yours, like the one that you've developed and the one that many other people have developed, including a lot of Australians in the solar energy field. But the impediment seems to be it's too hard, it's too expensive, it would wreck the economy and all that kind of thing. So it's refreshing to hear someone who's actually developed a system that really works and is implemented on a very large scale overseas, talk about it in terms of just having the clarity of vision that this is how we're going to produce our energy and make a decision on that basis.
Wolfgang: Yes, I think as long as you say it's too expensive, you actually mean you don't want it.
Mark: Exactly, that's a very, very good point.
Eva: You're very good at interpreting English, aren't you!
David: Wolfgang, we are just a couple of minutes away from needing to wrap up, it's been terrific speaking to you, and I just wanted to give you an opportunity I guess there for some final ideas and thoughts, what you've learned out of this amazing development.
Wolfgang: Well, I learned that if you keep your mind on something which first looks not possible and you just keep doing it without considering too much whether you earn money with it or how you make a living out of it, but you just do it because you feel it's good to do, then it works out.
Eva: That's an excellent philosophy.
Mark: When you go and see…I think there's an ashram in India that produces 50,000 meals a day, is that right, with Scheffler reflector technology?
Wolfgang: Yes, there are a number of ashrams, one is 50,000, the other one is 30,000 meals. It's quite spread here.
Mark: So what's your feeling when you go and see one of these places in full swing?
Wolfgang: To me it looks quite normal now because this is operating for the last ten years and I go there almost every year, and we do some new developments there. But these things now, to me it's very normal and I hope some day it will be normal to everybody.
Mark: If they hadn't existed, would those kitchens have been operated off wood still, do you think?
Wolfgang: No, these kitchens normally, these big kitchens they are not with wood they are normally operated by diesel oil.
Mark: Okay, well, they must represent a huge amount of emission savings.
Wolfgang: Yes, in one day they save about 400 litres of diesel in these large institutions.
Eva: We have to finish off in a couple of minutes, but I was just wondering if you, with all your wisdom, have some advice for us and for our politicians? If you were running Australia, if you were the minister for energy and the environment, what would you do to help us move towards a better future?
Wolfgang: If I would be in such a position I would immediately make a lot of these Citizens Reports with Planning Cells and find out what the people actually want and which way they are able to implement, because that is the best way to create a society which is very efficient, very forward and very social also, I mean a society of happy people. And once you have happy people then problems become less on any scale.
Eva: Once you have happy people the antidepressants are all thrown away, it's very exciting.
Wolfgang: Because then we are able to really do the things which make sense. Now we do too many things which are not making sense.
Eva: Absolutely. This Citizen Report with Planning Cells, is this being used extensively in Germany or…I'm very interested, I'm going to follow this up and we'll probably put some of a show towards speaking to someone more about this. Where can we read or find out more about that? And also what's the website that has the most information about the Scheffler dish for the listeners?
Wolfgang: For the Scheffler dish you look at the website of www.solare-bruecke.org and for the citizen panels I made a website with all the links that is called www.new-democracy.org.
Eva: Are we allowed to join that? Is that a social networking site yet?
Wolfgang: No, not yet. I'm working on it for the last six years but it's not so much developed, but in Germany it's used a lot. Once you follow the links you can see what all happened already.
Eva: Wolfgang, it's been an absolute pleasure speaking with you, you're a totally inspiring person and we need more people like you here in Australia. So please come and visit, it's very sunny.
Wolfgang: That's true, thank you. It's very nice talking to the other side of the world at this time, thank you.
Transcript by Julie Burleigh
