Source: Low-tech Magazine (only LED parts of the article quoted, highlights added)
October 14, 2008
Light Emitting Diodes (LEDs)
The drawbacks of CFLs are slowly gaining recognition even amongst critics of the incandescent light bulb. More and more, compact fluorescent lamps are considered to be an interim technology, awaiting the arrival of Light Emitting Diodes (LEDs) and Organic Light Emitting Diodes (OLEDs).
Strikingly, exactly the same thing is happening with biofuels, where advocates eventually accepted the unforeseen disadvantages but point to a next generation of technology which offers all the benefits without the drawbacks.
LEDs do not contain mercury and they are even more energy-efficient than CFLs, while boasting even longer life expectancies. However, also this technology still has to fulfil its promises.
LEDs have become a mature and clearly advantageous technology when it comes to coloured lighting – red, green, yellow. This makes them a very good choice for traffic lights, for instance. White light – the light that we need most to light up our homes and streets – is another story.
White LEDs are considerably less energy efficient, have lower life expectancies and can become very hot. High powered white LEDs are equipped with a fan to cool them down – introducing extra energy consumption, noise and breaking possibilities. Also, there is evidence that high power white LEDs can damage health. And last but not least: white light from a LED looks very much like the light of a welder: more blue than white, and everything but cosy.
Viva Las Vegas
At the moment, LED technology is no competition for the incandescent light bulb. However, it can be considered a worthy improvement of another technology: neon lights. And that’s the problem. Whether or not white LEDs will finally arrive, the success of coloured LEDs is a fact. New applications are appearing every day, and even though some of them are definitely useful, they all introduce lighting in places and situations where there was no lighting before.
Pasting many thousands of LEDs on a large building, with the sole purpose of decoration, seems to be the new hot thing in architecture. Dozens of examples (including the pictures on this page) can be found here, here, here, here and here.
The people behind these projects almost always emphasize the energy efficiency of the lighting technology used, but of course no energy is saved here, on the contrary.
The LED lights attached to facades (sometimes more than 200,000 of them) are not substituting incandescent light bulbs, they substitute a non-lit façade.
So what counts is the extra energy consumption introduced by these LED-curtains, not the energy savings compared to wrapping a building in incandescent lights or neon – which nobody would do, except in Las Vegas.
Gigantic billboards are another emerging application of LEDs. Bejing has two of them. Greenpix measures 2,200 square meters, another screen in the same city – placed not vertically but horizontally as a roof over a street – measures 7,500 m². In Dubai, a 33 story LED-display is planned, visible to a distance up to 1.5 kilometres, to be attached to a skyscraper.
Greenpix is powered by solar panels, and therefore it is marketed as “a radical example of sustainable technology”. Of course, it is not. It takes energy to manufacture solar panels. Introducing renewable energy lowers energy consumption only if it substitutes existing energy production.
Translucent concrete and luminous pavement
Two other recent inventions that should raise concern: translucent concrete and luminous pavement. In the near future, we will leave the light on in every room of our house, not for ourselves, but for the passer-by on the street and for the neighbours. LED-walls can display moving images, controlled by a computer. Every wall, every building, every bridge and every paving-stone could become a medium for communication.
LEDs could revolutionise interior design and the list of products that can be “augmented” by LEDs seems infinite. Some examples: taps and showerheads that change the colour of the water according to temperature, colour changing book shelves, illuminated clothing and accessories, slippers, safety clothing, garden lights, garden benches, speed bumps and crossings.
Some of these applications are worthwhile. Most notably, LEDs promise to make traffic safer. And many people will be thrilled by the emerging design possibilities. But this technology will NOT lower energy consumption, on the contrary. There will be much more lighting everywhere, and because this lighting is more efficient, the best that can happen is that energy consumption will not rise.
In fact, that’s exactly what the shopkeeper’s association in Madrid answered last December, when Spanish newspaper El País asked why there was such a striking increase of Christmas lights compared to the year before: “LEDs consume much less energy, so we can use much more lights without consuming more energy”.
The energy efficiency paradox
It is a common misconception that energy efficiency always leads to energy savings. This might be true in some cases, but not in most. Computers, televisions and car engines are good examples. All these technologies have become much more efficient during the last decades, but their energy consumption has been constant or on the rise.
Even the arrival of a radically new energy efficient technology – comparable to the change from Edison bulbs to LEDs – is no guarantee. LCD and plasma television technology is in itself considerably more energy efficient than the conventional cathode-ray tube. There was a potential for a reduction in energy consumption, but instead it was decided to use the technology to make larger televisions without raising power consumption (too much).
There are so many examples of the energy efficiency paradox that it is hard to believe that this mechanism (already described in 1865 by Stanley Jevons and further developed by Daniel Khazzoom and Len Brookes in the 1970s) is still so controversial. Maybe LEDs will finally convince us, because they promise to become one of the most powerful examples to date.
The paradox is very hard to prove for compact fluorescent lamps, because they did not bring about new applications. It could be that people are tempted to install more lights and leave them on for longer periods, because they know they consume less – but that’s very hard to prove, and not so likely either. With LEDs, however, the situation is vastly different. Your desk lamp might use less energy in 10 years time, but the technology that made it happen will also light the exterior of all buildings and infrastructure in your city.
More instruments needed
LEDs illustrate the danger of a purely technological approach to energy conservation. A technology that was originally designed to save energy, gives way to all kinds of new applications that might eventually raise energy consumption considerably. The evolution of technology is unpredictable, and therefore technology should never be the only solution to a problem.
Outlawing incandescent light bulbs – which several countries plan to do – is no solution either. The guy burning one light bulb in his little room (and maybe using the excess heat of his bulb as heating in winter) damages the environment a whole lot less than the guy on the other side of the street who decorates his mansion and garden like a casino with LEDs.
There is a lot of room to lower energy consumption without switching to new technology. Something is awfully wrong with our approach to energy conservation.
All this does not mean that energy efficiency is a bad thing. It brings economical gains and many other advantages: faster cars, more powerful and smaller computers, larger televisions. For many of us, these are all very important achievements. Energy efficiency also offers the possibility for a reduction in energy consumption, but this does not happen automatically.
More is needed to translate energy efficiency into energy reduction. A carbon tax or higher energy prices, for instance. Together with these instruments, energy efficiency can be a very powerful tool. Without them, energy efficiency works against us when it comes to saving energy.
© Kris De Decker (edited by Vincent Grosjean)