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Wednesday, October 22, 2008

Throwing Light On The Future | Focus

Throwing Light On The Future | Focus

This is a guest post from KuleKat
Light Bulb Everyone's heard of "low energy" light bulbs, haven't they? They save money and they're good for the environment too... that's right, isn't it? Without wishing to appear condescending, that's typically about as informed as most folk want to be. You fit a light bulb, you switch it on, it illuminates the place, hopefully the electricity bill might come down a bit (or not go up so much)... other than that who frankly gives a rat's backside?

Now, let me ask, would you try to light your home using electrical heaters, candles, flaming torches and the like? No? Well, if you're using conventional incandescent light bulbs you might as well. The common or garden light bulb we all know so well is a damn good heater that happens to also give off a very small amount of light - quite a bit less than 10% in most cases.

For every 100 watts of electricity you pay good money for to run a 100w light bulb, about 95 of those watts are completely wasted as heat. You're quite literally burning money, increasing demand for more energy to be produced, and pumping excess heat, all at the same time.

With lighting accounting for around 20% of total electricity consumption in most developed countries, you can immediately see there is scope for massive savings, financially and environmentally, if a more energy efficient form of lighting is adopted.

And indeed, this exact same thought has also occurred to many governments around the world, and they're so impressed with the idea that they're actually setting about banning incandescent light bulbs. Yes, you read that right. Depending on where you live, very soon you may simply not be able to buy a regular light bulb because it will be illegal to stock or sell them. If you live in the UK you have until the end of this year (as of now, just over 2 months) if you want to replace any 100w bulbs.

So, boring as it may be, you are shortly about to become rather better acquainted with the world of low energy lighting than you possibly wanted. Most people's first thought on the subject is likely be CFL (Compact Fluorescent Lamp) bulbs - the slightly oversized tubes and spirals that have languished unloved on shelves for a few years now.

The main reasons that adoption of CFLs has been so poor are that most folk a) given the choice, prefer the light quality of incandescent and b) don't actually understand the economics of lighting.

Let's take the first reason. There are, in fact, many problems with CFLs besides simply looking awful. The real killer, so to speak, being the 5mg of highly toxic mercury vapour that each CFL bulb contains. To prevent seepage into soil and water systems, used bulbs should really be treated as hazardous waste and the mercury reclaimed, which is expensive, a nuisance and being realistic, carte blanche for the idle, irresponsible and selfish to act otherwise.

Now you might think that the lighting industry would be busily addressing these serious issues. Well, this is Kaj den Daas, chairman and chief executive of Philips Lighting, speaking about CFLs: “We are not spending one dollar on research and development for compact fluorescents."

Jaw dropping stuff, huh? Well, actually, not quite. Because Philips, in common with other lighting manufacturers, regards CFL as a flawed interim solution and has instead devoted the bulk of its considerable R & D budget to LED lighting, which is where it firmly believes the future lies.

LED lighting? That's for torches and Christmas tree lights... oh, and you do see them in automobile lights, and come to think of it, traffic lights, and now that you mention it they've recently started appearing in shop spotlight displays.

LED lights are already fast replacing many forms of directional lighting (spots, halogen down lighters, cabinet and display strip lighting, desk lamps) which they excel at (and CFL’s are useless at). They last for 50,000 hours or more, run cool, produce all manner of different pure light colors and are lightweight, discreet and robust.

The explosive growth we are beginning to witness in LED technology and applications is reminiscent of the computer revolution a couple of decades ago, which followed a trajectory described by Moore's Law - that silicon chip performance doubles in performance every 18 months.

As it happens, there is an LED equivalent - Haitz's Law - which holds that every decade the price of LED lights falls by a factor of 10 while performance grows by a factor of 20. And, as an eerie echo of what happened with electronic computing, the luminous efficiency (light output per watt of power consumed) of home LED lighting is presently doubling every 18 months.

Here are just a few highlights from this year alone:
  • January 2008 - nano-imprint lithography significantly increases light emission of LED chips;
  • March 2008 - polarized LEDs to control direction and distribution of light, these could quickly replace LCDs for TV and computer screens;
  • July 2008 - significantly cheaper production as technology developed to produce LEDs on low-cost, metal-coated silicon wafers rather a sapphire substrate;
  • September 2008 - development of stable pure white LED light using a new phosphor from semiconductor nanocrystals of cadmium sulfide mixed with manganese;
You don't have to understand the details to grasp the underlying message. LED is a hot technology that is set to dominate all forms of lighting on this planet - real soon.

At present domestic LEDs are available that can produce 100 lumens per watt. For comparison, a 40w incandescent bulb produces nearly 400 lumens. Simple maths tells you that the equivalent LED is already up to 10 times more efficient, and, furthermore, is doubling that performance gap every 18 months while steadily dropping in price. The conclusion is inescapable.

So finally we get to the second reason that low energy lighting has thus far failed to take off. The economics of lighting. With our existing incandescent infrastructure, the cost of lighting is almost entirely made up of the cost of running it - the price of electricity. This is even discounting the fact that conventional light bulbs only last a thousand hours or so and therefore need to be replaced - a great deal.

But most people simply don't realise this. Faced with a choice between a regular bulb for $0.50 and an equivalent LED priced at, let’s say, $50 they pick the "cheap" alternative. The startling truth is that even if incandescent bulbs were FREE they would still cost you far more money than the (presently rather expensive) LED bulb to light your home.

And so once again the carrot and stick of economics and legislation are dispatched to do battle with ignorance and indifference over the really rather important issue of how we light our planet at night.

The outcome is hardly in doubt, of course. I'm no fortune teller, but I do know what you, me and most everyone else will be using to light our homes a couple of years down the line. The alternative to LED will be darkness, simple as that.

If you’re interested in finding out much, much more then visit LED Home Lighting.

KuleKat is interested in the defining features of our times (climate change, oil depletion, technology and so on) and what it all means and more importantly what WE as individuals can do about it.


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