Green lighting revolution
Mike Ford: My name is Associate Professor Mike Ford, I'm the Head of Physics here at UTS and it gives me great pleasure to introduce my colleague from the department Professor Matt Phillips who will give tonight's talk. Matthew received his PhD from UTS in 1991 and has since then gone on to do great things. He's developed an internationally recognised research program here at UTS in materials physics. He has been instrumental in developing and establishing a world class research facility the Microstructural Analysis Unit here at UTS, of which he is currently the Director.
He has served as Deputy Director of the UTS Centre of Materials Technology from 1998 to 2000 and subsequently as a Program Leader in the Institute for Nano scale Technology. Most recently he's established the Green Lighting Research Group here at UTS with aims at developing the next generation of environmentally friendly energy efficient lighting, based around LED technologies. This is something that we're obviously going to hear quite a lot about tonight.
He's held a number of visiting fellowships throughout his career, both in Australia and overseas. In 1992 he was awarded the Cowley Moodie Award from the Australian Microscopy and Microanalysis Society. He has co-authored over 200 contributions to scientific literature and given numerous presentations at international conferences.
With that I'd like to invite Matthew to the stage to give tonight's UTS engaged talk. A talk about science taking place here in the faculty of science, science that has potential beyond the boundaries of the laboratory, where it is conducted and science that has impact for all of us, the Green Lighting revolution. Matthew.
Matthew Phillips: Well thank you very much Mike and good evening ladies and gentlemen and thank you all for coming to my presentation tonight. Tonight I'm going to tell you about a revolution in lighting, and what we're going to see over the next decade, is we're going to see something - well a hundred years of lighting technology can be completely replaced by a new type of lighting. That's inexpensive, clean and efficient and which is based on solid state devices rather than heating filaments with the standard incandescent type bulbs.
Okay this transition between the existing technology and this the new solid state technology, has already commenced. If you look around you'll see that most of the traffic lights, something like 80 per cent of the traffic lights have now been replaced by LED type sources. Most brake lights in cars now consist of LEDs. These are street lights that have recently been installed down in Martin Place which are made of semi conductor light emitting materials. School signs that are hooked up to solar panels, advertising signs, large screen displays at sports stadiums. Back lighting for LCD type display monitors and mobile phones, and also as we'll see portable lights as well.
So when did this all start? Well you can actually it's difficult with a lot of technologies to actually place a certain time and place or even or breakthrough which you can attribute to a whole new generation of technology. But not in this case, Professor Nakamura basically in 1993 made a significant breakthrough and developed the first ever blue LED. Now why this was so a jaw dropping result or discovery was that for many many years, it was always deemed to be or considered to be impossible on theoretical grounds, for producing this type of Light Emitting Diode, or semi conducted device.
Nakamura when he started at Nichia, he'd just finished his master's degree and he went to work at Nichia in Japan. While he was there he ignored everyone else's comment about this being impossible and he just beavered away, and then he was able to make this breakthrough. Why this is so significant is we'll see tonight that this is - this single breakthrough has enabled the development of a whole new generation of energy efficient lighting, and this is what we'll be looking at and talking about tonight.
So what I'd like to do is just start, given this is a public lecture, just start with some of the basics about light. As we all know from Pink Floyds album, Dark Side of the Moon and also of course Isaac Newton, we know that white light is comprised of colours, ranging from red, orange, yellow, blue or green, blue, indigo and violet. Our eyes are a tremendously good detector; it can detect over 10 million different combinations of these various colours of light.
The eye though doesn’t detect these colours in a linear fashion, so you can see from this profile here we've got colour or wavelength on the X axis and intensity or signal on the Y - on the vertical access here. We can see here that your eye detects most predominantly the green and blue - sorry the green and yellow colours, and to a much lesser extent the blues and violets and the reds and orange. So the eye basically is geared for detecting these green hues.
So how do we actually go about measuring light source performance? Well we use a unit known as lumens per watt. So first of all what's a lumen? A lumen is a measure of light output and to just give you a feeling or so you can relate to this, a candle for example emits around 12 lumen in all directions. If we look from one side of the candle and we're about 30 centimetres away we see that it emits around one lumen. I'm sure most of you are familiar with the unit of a watt, it's just a measure of electrical energy, and it's just the product of the voltage by the current.
So when we say we're measuring lumens per watt, which is known as the efficacy of the light source, we're measuring the amount of visible light, and that's important that's being produced for each watt of energy that we're using. So for a traditional incandescent light bulb, this value is around 16 lumens per watt. Okay so that's equivalent to around 130 candles. If we look at the efficacy, one thing we should just mention is that it's basically the conversation of electrical to optical power, but it also takes into account the conversation of the optical power to lumen that's sensed by the eye.
Remember before our eye was highly nonlinear, so this means the maximum efficacy we can get out of a light source is around 680 lumens per watt, and that actually occurs on the green. So we'd only get that if we just had a pure green light source. Because of that you can see how the efficacy drops off into the blue and violet regions and also into the orange and red areas of the spectrum here. So because of this that the maximum, because it's dropping off, if we want to produce white light, we need to have components of colour over the full visible spectrum. Because of this the maximum efficacy that we can actually achieve for a white light is around 325 lumen per watt.
Okay there's some other important parameters that define or the performance of a light source. One is what's known as a colour rendering index and this basically describes the ability of a light source to reproduce colour. It ranges from 100 for sunlight and a standard incandescent bulb, all the way down to 40 for a sodium vapour lamp, which is basically what you have in streetlights. We can see here how the colour degrades, so here we've got in sunlight or incandescent bulb, and as we go down towards a streetlight type of lighting, we see that the image becomes much bluer.
So here's another example showing the same thing, this painting under an incandescent bulb showing vivid colours, and then the same image being displayed under a streetlight. Showing the washed out or flat colours.
Okay the third performance parameter that's important with comparing light sources is something known as the colour temperature of the source, and this is a measure of how white the source is. This ranges all the way through from a reddish type white which gives us this warm type of lighting, all the way through today lighting and LEDs and fluorescent type lighting. You can see here that it gets whiter and bluer and this is described as cool white. This is actually given a temperature here, but basically the lower this temperature, this is a unit of temperature. It's Kelvin which is you can just correct for converting this into Celsius or a standard or common unit, but it's just a measure of temperature. The important point is the smaller this number, the redder or warmer the light source will appear.
So again just showing you an example of this, just a car park here being lit on the right hand side by LEDs and on the left hand side being lit by incandescent. So let's just have a quick look at the history of lighting, and of course lighting has played a very important part in the development in communities. In that it's essentially for enhancing the society's productivity and prosperity, its health and wellbeing and its safety and security at night.
So evolution of lighting, well of course the first was in prehistoric times was just simply a flaming torch, and then from around 7000BC to the present times, in fact two billion people still use these types of oil lamps. These came on to the scene and then after that we had gas lighting, so a big jump in technology in terms of the timescale. Gas lamps became the predominant type or mechanism for providing community lighting. Then after or around the same time we had the Spermaceti candles that were from wax from the whaling industry. These were very popular because they were smoke free and odourless. Then around 1800 we had the development of the arc lamp then after that the kerosene lamp. I can still remember at my grandfather's weekender using these in the sort of 1950s, so they certainly stayed around for a long time.
Then we had the development of the incandescent type bulb, which everyone is I'm sure quite familiar with from the work of Edison and others. This then this was the original bulb had some carbon filament, this was replaced 20 odd years or 30 years later, with a Tungsten bulb, Tungsten metal bulb and this allowed the - considerably extended the lifetime. After that surprisingly fluorescent tubes came on to the scene in the 1940s, and then in the 1970s the more modern incandescent bulb the Tungsten halogen became available. Then after that the compact fluorescent bulb and then finally and what we'll be talking about tonight the solid state LED bulb.
As this lighting has progressed through history what we see is that the performance or the efficacy of these light sources has improved significantly. So if we look at the candles that were available in the 1700s, they had an efficacy of about 0.3 lumen per watt. Light bulbs as we saw earlier around 60 lumen per watt, the compact fluorescent 50 lumen per watt, the high intensity discharge lights that are used in streetlights around 100 lumen per watt. As we'll see tonight what's available now commercially is the solid state light, which is up at 150 lumens per watt. So we've had this increase over time in terms of the lighting performance.
If we look at individual sources, we can see that they seem to fall into three different groups, or four different if we include the lighting. But each one of these with time tends to flatten out, so we can see here in terms of the performance there's a modest increase, and then from about the 1950s this plateaus out. There's been no real significant improvement in fluorescent lights since their introduction. But finally we can see where there's growth is in the solid state type of lighting.
From 1910 Australia banned the incandescent bulb, and this really heralded the start of the energy efficient lighting revolution. We weren't the only country, others countries have followed suit, so most notably the United States will phase out all 100 watt incandescent bulbs by 2012, and all bulbs by 2014. The European Union has legislated to ban all incandescent light sources by 2012 and as I mentioned earlier Australia has already banned these bulbs this year. So if you go to the supermarket you'll see that these shelves are empty, there are no more incandescent bulbs.
So the question is why have governments around the world done this? Well if we have a look at a picture produced by NASA looking at the earth at night, we can clearly see the various countries, the lighting is produced. So these bright areas at night are the lighting or the light that's being produced by these various countries. So the USA, Europe and Japan, and it comes as no surprise that lighting research has dominated in the countries of Japan Europe and the USA. So this shows a number of things, one the wealth of these various countries, two the population density of course, but also the power usage that's used every day in generating lighting.
In fact 20 per cent of the worlds electricity is actually consumed in providing lighting, so a significant amount. If we look at the old incandescent bulb, we said earlier that it has an efficacy of around 16 lumens per watt. But if we can see here this here represents the light output that most of the light output of an incandescent bulb is actually in the infrared region, and only a very small component of the light that's being emitted is emitted in the visible. So it's a very inefficient light source, in fact only five per cent of the energy is provided in generating light. 95 per cent of the energy has lost its heat.
Okay, so this is a very inefficient light source, and at the time compact fluorescent lights had come on to the scene and we can see here when we do a direct comparison. One of the efficacy or the performance of these light source, we can see 60 lumen per watt to 50 lumen per watt with a compact fluorescent. So it's around three time more efficient and we can also see there's significant increase in the lifetime of these sources. From 1000 hours to 10,000 hours, so a factor of 10 increase in the lifetime of a compact fluorescent.
So if we look at the Australian case, the average Australian house has around 20 light fittings. The USA has double this amount, we can make an estimate, three people power house, 20 odd million people, there's around seven million houses. So that means there's around 140 million light bulbs that will be replaced by compact fluorescents. So when you start looking at the energy savings based on this better performance here, 50 lumen per watt and the extended lifetime of the device.
We see some staggering numbers, that Australia will save, by this initiative to ban the incandescent and replace it with compact fluorescents. It will save of the order of 30 million million watt hours, it will save $4,500 million dollars and it will produce 28 million less tonnes of greenhouse gas. This is the equivalent of taking around half a million cars off the road or closing down one coal powered electricity generation station. So this initiative has some significant outcomes.
However there's some serious issues with compact fluorescent lighting and when I go through these you then really have to ask questions about how green are these light sources. The first is each one of these lights contains, I've got one somewhere, these contain around four milligrams of mercury, and that's enough to contaminate of the order of 100,000 litres of water. Second is that they're quite fragile and easy to break, I mean the first time we put one of these in one of our lamps in the lab, someone was screwing it by the top of the glass and it just snapped it completely off. I'll talk about that in a minute.
We'll see that these light sources, just by the way they work, they actually emit a very large amount of UV, ultraviolet light, and this of course can have consequences in skin cancer or eye damage. So if we just see here, this is the output of the incandescent bulb and we can see here this is the output of the fluorescent bulb, again this is colour on the X intensity on the vertical access sorry. So we can see here there's these extra lines in the ultraviolet.
The disposal then of these compact fluorescents becomes a serious issue in terms of the environment. To give you some idea of the scale, before the American that converts across from incandescent to compact fluorescents, they already dumped the order of half a million fluorescent tubes per year into landfill. Finally as we'll see although these are impressive figures in terms of lifetime and efficacy, when we compare this to a solid state light, it certainly lags behind.
Just to give you some idea of this, I just pulled this off the web; this is the US Environmental Protection Agency, of what to do if you break a compact fluorescent tube. You can see the instructions are open a window and leave the room for 15 minutes. Place all the debris in a glass jar with a metal lid. If you break it on clothing or other bedding material, you throw it out. Don't wash it because you'll contaminate the machine and cause pollution. You can't in a lot of cases just throw it in the rubbish bin; there'll be a specific place where you need to take it. Finally it says that you need to sort of go through these every time you vacuum you should air the room out. So it is questionable about the greenness of this sort of technology.
Now what I'm going to move on to is light emitting diodes and we'll see that these particular sources are clean and efficient lighting technology. It's a very good alternative to compact fluorescents. So first of all what is a Light Emitting Diode or a solid state light source. Well to put it in simple terms, a light meeting diode is a semi conducted device that converts electricity very efficiently into light. It consists of two types of semiconductor, one where some chemicals have been added to increase the number of electrons. Then on the other side another piece of semiconductor where some - again some elements or material have been added to reduce the number of electrons.
Then when we've put a voltage across this junction between this negative area and this positive area, we force electrons to flow across the device. When these extra electrons fill these holes or missing electrons, it then produces light. It does this very efficiently.
Okay well LEDs have been around for 30 years, I can remember playing with these as a student, they were fantastic in the 1970s, they were freely available. So what's different? Well these new devices that we're going to talk about tonight are based on nitride and oxide semi conductors. Not silicon or gallium arsenate that have been used in the past. So these are the typical types of material, this is the element indium, gallium and nitrogen and here's aluminium nitride and the final one there is zinc oxide.
The important thing is that these particular materials can be used to produce extremely bright ultra violet blue and green LEDs, or Light Emitting Diodes. So the question is so what? Well with that simple breakthrough or technology we're now able to produce extremely bright white LEDs that now have efficacies up of the order of 200 lumens per watt.
So how do we do it? Well it's quite simple, first approach is we use a multichip device which consists of three LEDs, one that's red, one that's green, one that's blue. We can see that when we mix all these colours of course we get white light. So this is a great approach, we get a fantastic - besides white light, we can adjust the intensity, relative intensity of these devices in any way we like. We get very high control over the colour it has theoretically the bets efficiency. The drawback is this is a high cost device because it consists of three different LEDs.
And alternative approach here is the use of a single blue Light Emitting Diode, and then in the encapsulation surrounding it, we include some phosphor material that converts some of this blue light. So this is absorbed by these little particles, and then when it - then after it absorbs, it then reemits some of that light at a different colour. So we can see here this is in the yellow and red. So although this looks like this, there's a blue pig and a yellow pig. In fact how we perceive that is we perceive it as a bright white LED.
This is how most of these devices are produced at present, it has lower control over the colour and slightly lower efficacy to this approach. But the significant advantage is a much lower cost to produce these devices.
So with today's LED lighting, these devices are already twice as efficient or have twice the efficacy of compact fluorescents. They have five times the lifetime, and so immediately with today's technology if we implemented these devices, we would double the power cost savings, and the cost savings, energy savings and the environmental benefits. In fact the US Department of Energy report showed that with today's technology, if we replaced compact fluorescents - sorry the incandescent and compact fluorescent with solid state lighting.
Over the next 10 years we'd be of the order globally saving of around $1,800 trillion. We would reduce pollution by 10,000 mega tonnes of Co2 gas and we would have a significant decrease in the amount of energy consumed, about 18,000 terawatts or a million million watts. Eliminate the need for 280 power plants and eliminate the need for around 1,000 million barrels of crude oil. So these are really staggering figures.
In addition to that if we look at what's happening with energy consumption, we can see that over the next 40 years, the energy consumption globally is going to double. Mostly being driven by the development of China and the rest of Asia. Also it comes as no surprise that energy's going to become more expensive. So at the moment we pay around 18 cents per kilowatt hour, that's really low on an international comparison. Other countries in Europe might be paying up towards 40 or double that or even more. But nevertheless so it's certainly in time increase. As these consumption and costs increase the cost effectiveness of starting to use or these LEDs becomes greater.
So what's the holdup, if this is so good why don't we just go and replace all of our lights with fluorescent lights? Sorry LED lights. Well it's a factor called the Cost Per Lumen, how much does it cost us to produce this light? So if we look at an incandescent bulb, this is incredibly cheap, it costs us around 30 cents, these are US figures, 30 cents per kilo lumen, 30 cents to produce 1,000 lumens. If we compare that with a compact fluorescent, again with about the equivalent output and performance, we see here that it costs us around $2 per thousand lumen. So it's still manageable.
If now we go to one of the currently available this year solid state lights, we see the cost of an individual bulb is of the order of US$60, so this is costing us US$100 per 1,000 lumen. So this is now, this is the issue. There has been significant improvement, we can see here in 2003 this figure was 350 and 2006 it dropped to 120 and now it's dropped 2010. It feels here there's been a number of major breakthroughs which we'll talk about in a minute. But mostly the US Department of Energy is quite confident that this cost will decrease from US$60 per light source down to around US$16 per kilo lumen by 2015.
So how do we go about reducing it and this is one of the main areas of interest to the research group at UTS. Well there's two ways of course. You lower the cost of the LED itself, or you increase the amount of light it produces. Lowering the cost of LEDs, there'll be certainly as the economy of scale and more people buy these devices. We'll certainly see a decrease like any semi conductor technology, we'll see a decrease in the price of individual devices, that's clear.
But if you look here, this is one of the devices that are currently, they're a little bit more complex than the diode that I showed you, or the textbook diode that I showed you earlier. We can see these are manmade structures, they're made in reactors chemically and they consist of around 36 different layers that have grown atom by atom. So this process is inherently expensive, and to actually get them to perform we need very precise control over the concentration of the chemicals we include and their thickness. So it's always going to be relatively expensive compared with CFL and incandescent bulb product, but it will certainly decrease.
The other way is to increase the light output, so how do we go about that? Well again there's what scope do we have here? Well currently you can buy commercially on the web, around 90 lumen per watt light bulbs or LED bulbs. This year one of the American companies reported, this is again a jaw dropping result, out of the blue they announced three industries in the United States announced that they're able to produce in the lab, LED that produced 208 lumens per watt. Because we mentioned before the theoretical maximum is somewhere in the order of 325.
So what can we do? Well there's a number of areas we can attack. We can improve the light emission from the material, so make better quality semi conductors. This is something that our research group focuses on, so we're around 60 per cent efficient in that area. Light extraction, a lot of the light is reflected back into the device. So with some novel physics we can basically get around some of the issues or that cause this effect, and we should be able to improve in that area. The phosphors that are included in the encapsulation can be improved, the way light interacts with these phosphors.
Then finally the packaging improving the electrical contacts and the amount of light scattering in the device. All of these, even small changes are incremental in these three areas will make a big difference, but we can see here, the two areas labelled in red are the ones we really want to focus on.
There's one other thing I should mention to be fair to this technology and one of the challenges with it. It's LEDs dark secret, and it's known as efficiency droop, and what happens here, so this is for example is a device that was released by [Cree 0:34:40] as a commercial product this year. We can see here that at 300 megs, you're using a current of 350 milliamps, the output is around 160 lumen per watt. This is very impressive output, but when we drive it up to two amps, we see that it drops about 30 per cent in its efficacy performance.
Although I should say that this is still very impressive, 800 lumens, it's equivalent of a 60 watt light source, using only seven watts. It's still very impressive numbers, but it'd be much more impressive if we could get this level of performance. This resolving what causes this is one of the main issues that are being addressed and attacked by the community. Because what causes it, the reality is at the moment no one knows.
Okay you'll notice that when we look at these LEDs that they're surrounded by all of this metal sculpture. The question is these are supposedly highly efficient cold light sources, why is all this metal here and so on. Well if we look at just a conventional light bulb, we said earlier that most of the energy is consumed with producing infrared light or heat. But in this bulb there's a filament that's heated up by a current and this heat can then be just dissipated to the air through the encapsulation.
In an LED the light emissions certainly cold, from coming from the junction here between these two different types of semi conductor. But there is a resistance here and if we're passing high currents through this resistance, this heat has to go somewhere it's not going off as light. So it travels back down the leads that are supplying this current and heats up the electronics. So that's why if you see at the base of these LEDs there's all of these metal things, they're there to increase the surface area so that the device can lose heat efficiently without it going back in to the electronics.
Okay, we're going to - just before I go into applications, what I'd just like to show you and I hope this works, are just some of the devices that are available. So most of these I just brought down at the local Jay Car shop, and one of these which I'll show you we got from China. So I don't know how well this will work, but let's have a go.
Okay so the first light I'm going to turn on, this is a standard quartz halogen lamp, it's 50 watts, it's producing 850 lumen, so this is the light intensity here, it's doing that at about 17 lumen per watt. Okay so let's look, this is a - as I mentioned something you can buy off the shelf in one of the electronic shops. So this is a 450 lumen, so it's not as bright, but it's getting up there. The difference is this is only using five watts, it's using 10 times less energy or power sorry than this. But it's not a huge difference, you can see the difference in the colour temperature, this is a bit yellower. Whereas the LED is much bluer, so it's a colder source. But in terms of performance it's actually using 10 times less energy.
That one has three LEDs in it, this one here is one of the newer, well at least newer for Australian, there are much better performing ones or sources available in the states. This is just a little three watt; this has been made because people actually prefer that warmer colour. So by just adding some different phosphors there, we can actually tune this colour so we can make the light warmer rather than the colder more intense source here. But they're both LED sources. This one is just using three watts to produce this light.
Number two is - this is a single diode and it's 90 lumen for what output and using four watts. Now remember these will last of the order of 100,000 hours, so the order of 50 years. So basically once they're installed then the question then you have to ask is do I need sockets anymore. Because probably the 100,000 hours is I think at best a guess by these companies, and I think they find that the electronics around these LEDs is more likely to fail before the light source.
Okay, so here's another gadget, we're familiar with this one. This is just a 60 watt light bulb. I'll just turn that on to give you some idea. So that's using 60 watts, and this here, as someone described looks like a bit of a dalek, this has 250 LEDs. This now is only using 12 watts, it's using one fifth of the power of this, and again the lifetime of this is probably of the order of 100,000 hours. The lifetime of this bulb is of the order of 1,000 hours, so it's 100 times improvement in the lifetime and it's 100 times longer and it uses one fifth the power.
I'll just finish - so these use incredibly small amount of power, I won't point this at you because - now what this is, after the talk you're more than welcome to come and have a look at these. This device here consists of seven - just counting the number of LEDs here, maybe nine by nine. So it's a little panel and I just have to be careful with this, because - so this is available from China, this is using five watts. So these are - there's another one available a 100 watt version of this, so this is 4,000 lumen and there's another one we were hoping it was arriving for this talk, which is getting to double that. But again only using 100 watts. So these are staggering light efficiency output.
Remember also that the power of these is incredibly small, so for example this is a little torch or flashlight. This is running of three triple A batteries, and you can see here just showing the packaging of the LED assembly. This produces quite a bright source of light for a very small amount of power. Because of that there's a whole bunch of other things you can do and you'll see out there in the market. Some of them I think are useful like these little wind up torches here, you can just wind away, and they say if you wind for a minute, which I won't do, that these will then last for around half an hour or so of lighting. There's another version of this where you basically just shake it up and as you're shaking it up you're inducing enough current into a little charge storage capacitor or something. Then we turn that on and we have light as well, so this doesn’t have any batteries or any just an LED source, and little inducer.
Okay so having done that, let me move on to some applications of where this technology's being used. Okay so one thing I'd like to mention, which we've talked about the improvement in the efficiency of these devices, but there are quite a number of other advantages of LEDs. We mentioned the fact that these have extremely long lifetimes but because they're solid state, they're not made of a filament or a glass encapsulation. These are incredibly robust and shock resistant, as we saw before they're quite small of the order of a few millimetres. They don't radiate any heat from the front it's a cold emitter, they're extremely light weight, they have an instant switch on time. They're non toxic, they're mercury free, and lastly they have a suburb control over the colour of the device or its degree of whiteness.
So I'll just - based on all that is obviously a number of terrific applications with this technology, first of all I think most of you might have noticed. As I mentioned at the start of the talk that around 80 per cent of all traffic lights have now been replaced with LEDs. Because of their efficiency, they save around $600 per year per intersection; their lifetime is 12 years or probably more. So there's no maintenance costs, so the payback time on buying these light sources is of the order of around one year. Then again you do the multiplier effect of how many intersections there are, you can see that there are substantial savings to be made.
If you wander downtown you'll see that the City of Sydney is about to replace all of its streetlights with LEDs. They're now testing 250 of these around Circular Quay, Martin Place, Alexandria and Darlinghurst. There are four companies I believe vying for the contract. So they're being lit up along Martin Place to check the performance of each of these. Again just to look at the scale of the savings that will be made by changing over this lighting technology. The City of Sydney has around 20,000 streetlights; the electricity cost for powering these is $3.5 million. They use three million kilowatt hours; they produce 13,000 tonnes of Co2 greenhouse gas. The maintenance costs on changing them over and keeping them running is around $5 million.
Australia wide again the multiplier effects, we've got two million and I'll let you read through the figures. But by changing over to LED street lighting, there'll be an immediate reduction in all of these areas of around 50 per cent. In fact because of this, these are significant savings and will be savings right across the world. We can see here that globally it's expected this market, just for LED streetlights. Should grow from about currently which is sitting at around $108 million in 2008 to around $1 billion in 2011.
So just again just showing you the difference performance, this is a street in London, one thing we'll talk about in a minute, these save considerable amount of money, these are solar powered streetlights. Of course the 20 year lifetime is going to make a significant saving in the maintenance costs of these devices. What I was looking at on the web when I was preparing this talk, what I was staggered to see was how many companies have actually sprung up in the last month or more that are selling these devices. Some of them actually have a number of case studies and this company here Spectrum Lighting was proudly displaying this as one of its case studies.
I think it gives you an example of the savings that could be made, this SOS Print Media in Alexandria replaced 480 of its fluorescent tubes with this. It basically looks like a fluorescent tube, but it's just studded with LEDs right along its length. They immediately saved $25,000 a year on their electricity costs, the production or the power reduction they were able to achieve, they were then using around 150 tonnes less Co2 emission. Of course the maintenance cost would also then weren't added to this either.
So they estimated that the return on the investment of refitting out their whole warehouse with LED lights is actually paid back in two years. Then you've got these devices for another 48 years or so at least.
Okay, brake lights, you'll see if you look at brake lights now are more array like consisting of all these little bright dots. These are LEDs, why are these attractive? Well if we want we can put LEDs behind here, but in most cases you can just have clear coloured and just tune the lighting to it's a red emitter. So there's no need for any filters, so you get much higher brightness. They're highly directional so they're coming straight out the back of the car, we have the long lifetime. They're robust of course because they're a solid material, not a filament. If any of them did fail by chance, there's no catastrophic failure as you would have with a normal incandescent bulb.
What you'd have here is just one of these go out, or alternatively the lights just get slightly dimmer. I should mention that, when they talk about the performance of LED devices. What they're in fact talking about when they say the lifetime is 100,000 hours. Is that the brightness drops to a level that's 70 per cent of the original level. So even then it's still a reasonably bright source, it doesn't blow like a filament.
The other thing is, as I mentioned earlier, that these are instant on, they turn on in a very short amount of time. This is around a thousand times faster than an incandescent bulb, these are thousandth of seconds and what are these, millionth of seconds or thereabouts. But when you're travelling on expressways at high speed, just having that faster switch on time, means that you actually reduce the stopping distance by about eight metres.
The use of architectural applications, I'm sure everyone was familiar with the energy games, and the water cube, this is lit by half a million LEDs, the American company Cree. Also the birds nests and also for decorative lighting, this is the bridge up on the American Canadian border.
Okay so what's the future? You might say well okay well I'm going to replace all the light bulbs in all of the developed world, then what do I do as a company once I've done this? These light sources are now going to sit around for 50 years or more, my markets nonexistent anymore. Well as I mentioned earlier, if we look here at this image of the earth at night, we can see there are very large portions that don't show any real major areas or patches of light at all. In fact over two billion people don't have any access to electric light. In fact I read, I think it's more people now don't have lighting than at the time Edison invented the incandescent bulb.
So as we mentioned this type of technology is perfectly suited for bringing lighting to these developing countries. Because of their low power requirement, they complement very well solar energy technology and advances in battery technology. These can be then implemented or installed on the top of various villages to restore and collect electricity. Then of a night then use the power these very efficient LEDs. IN fact you can see this if you - these are springing up all over Sydney as well, this is at the south end of Bondi Beach. Now we can see here this is basically a solar powered light, it's just basically erected and stuck in the ground here. Then after that it collects sufficient amount of power through the solar panels during the day and then it uses that stored power to power the lights during the night.
So there's no doubt that this is an area, even in Australia and other places and US and Europe. Where the use of sustainable renewable energy is even at current levels, this is a building in Portland, it's six of these wind turbines sitting on top of a high rise building. I’m not quite sure what that powers used for, but I can say it's lighting I guess, some low service that has a low power requirement. This is probably extreme, these panels of solar collectors all over the roof. But this is the sort of idea where you can actually use these alternate forms of renewable energy to power these types of - the devices which have low power requirements themselves, so the LED lights.
Just very quickly before I finish, just some other concluding comments. The other big development is in deep ultraviolet LEDs and these aren't used for lighting of course, but they can have a significant impact on portable devices for providing water purification and sterilisation. Plus a large number of other applications as well. I should also mention that what's coming on to the scene is now organic light emitting diodes, this is a rapidly developing area. They're starting to make or produce some of the materials here that have some impressive metrics on their performance, 60 lumens per watt and lifetimes of 10,000 hours. They're not high current devices but they're certainly going to fill certain applications, so flexi screens and so on, large area displays and lighting say in museums and so on.
So just to conclude here, to just show you how quickly this is all moving, that this is the Department of Energy roadmap on where they would like to see solid state technology develop and what rate they felt it should develop over the next 20 years. You can see here that what they wanted was they wanted efficacy of around 150 lumen per watt by 2012 and by 2020 they would like to see this to be around 200 lumens per watt. As I mentioned earlier in the talk Cree Industries have already got to the level, 10 years ahead of their target.
A fellow from [agelant notice 0:54:56] very similar to another one of these relationships Moore's law about how many components you can fit on to a semiconductor. He also noted some similarities with the LED development, and he found that every 10 years the amount of light generated by an LED increases by a factor of 20. While the cost per lumen falls by a factor of 10, and so if we continue this on, it's obvious that within the next decade all lighting will be replaced by LED technology. So LEDs are certainly here to stay.
So just to show you I started my research career after I finished my PhD looking at these nitrides that are used to make these devices. At that stage 20 years ago they were just a curiosity, they were an interesting material to study we knew they emitted a large amount of light and we wanted to understand why. In 20 years this has developed into a revolutionary technology and where this goes from here I'm not entirely sure. But I'm sure it'll be developed into a much more efficient devices. We have a centre at UTS that is looking at all of these properties to conduct research into this area. The Centre For Advanced Materials For Sustainable Energy and what we have here is a number of groups. One my group here looking at solid state lighting, other groups looking at battery technology, others photovoltaic's. Groups looking at plasmonics that can enhance the performance of these technologies, day lighting physics, bringing natural light into buildings and houses, and also compu - underpinned by computational modelling.
One of our initial goals is to see if we can - what we'd like to do I know it's sort of a stretch target. But if we could say that in principle with this technology with high performance photovoltaic's and high performing batteries to store that energy and high performance low power requirement LEDs. That it's conceivable you could take all domestic lighting off the electricity grid in the future.
So what I'd like to do is just thank a number of my research collaborators, industry collaborators Blue Glass an Australian company that fabricates nitride and semiconductor LED devices. FEI an American company and these universities and thanks for listening.
Back to the UTS Science in Focus: Green Lighting Revolution video
19 August 2010 57:50
Tags: physical science, green lighting, solid state lighting
Solid State Lighting: The future lighting technology - more sustainable, responsible and economical
Australia has officially outlawed the sale of incandescent light bulbs this year to advance the use of energy efficient and eco-friendly lighting technologies. The existing replacement strategy is based on compact fluorescent lighting technology, which will deliver considerable savings. The change alone is expected to save around 30 terawatt hours of electricity and 28 million tonnes of greenhouse gas emissions, which is equivalent to taking more than 500,000 cars off the road permanently.
Exciting breakthroughs in photonics and semiconductor research have been recently exploited to develop a new type of light emitter, which can be electrically driven to produce an extremely bright source of light. These new low voltage solid state lighting (SSL) devices are compact, lightweight and long-lasting. The implementation of this SSL technology will significantly lower the world’s electricity consumption, provide attractive cost savings and enable major environmental benefits through the reduction of greenhouse gases.
In this talk, Professor Matthew Phillips discusses the science, technology and applications of SSL devices, together with the major obstacles that must be overcome to facilitate the widespread use of this new green lighting.
About the speaker
Professor Matthew Phillips is Professor of Applied Physics and Director of the UTS Microstructural Analysis. He has been Associate Head (Research) of the UTS Department of Physics and Advanced Materials since 2006. In 1992, he received the Cowley-Moodie award from the Australian Microscopy and Microanalysis Society.
In 2008, Professor Phillips established the Green Lighting Research Group at UTS which aims at developing materials for the next generation of energy efficient, environmentally friendly, solid-state lighting. He has presented over 30 invited conference papers at international conferences and seminars in overseas laboratories and has co-authored over 200 peer reviewed publications.
UTS Science in Focus is a free public lecture series showcasing the latest research from prominent UTS scientists and researchers.
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