Carrying on from the LED discussion on the Nobel Prize thread:
I suppose the main view I have on the LED story is, whether the search for the high power, high efficiency white LED is pushed on by the following needs. (Nb: I'm not into any of that "conspiracy theory" stuff).
The current push for LED technology is a good idea because it will:
1. Conserve the Earth's finite resources or
2. Reduce the demand for electricity and thus reduce CO2 emissions or.
3. Reduce the demand for electricity, thus causing redundant assets to be closed and providing real savings for generators, due to reduced overheads which could be passed on to consumers in the form of lower bills or.
4. Reduce demand for electricity, allowing redundant assets to be closed and providing real savings for generators, due to reduced overheads which could be passed onto shareholders in the form of higher dividends or.
5. Provide a valuable and intellectually controllable technology, which could in theory be licensed to LED manufacturers - like GM bio-technology.
Unfortunately I cannot see LED generating any power savings on a global scale. History has proven that the more efficient lighting becomes the brighter and more widespread it becomes.
Take UK councils. When streets were lit with mercury and tungsten, you may have found 250W mercury lamps on main roads and 100W tungsten lamps on side roads. What about the present day? You may find that these same main roads are lit with 150W SON and the side roads with 70W SON. Power saving? Yes, if it weren't for the fact that there are more columns at closer spacings now, plus more roads are lit as main roads than in the past, and roads that were previously unlit are now lit. There is also the present day. Now that LED is being introduced councils are starting to move away from the recent policy of reintroducing part night lighting and switch offs. Whilst that is a good thing in many places, there are a number of roads and motorways which don't actually need lighting which are now less likely to be reviewed and have lighting removed. Funny how the number of motorway lighting switch offs has slowed down since the introduction of LED.
It is also all well and good showing evidence of how LED technology is more energy efficient, but how is it in practice? For example, some of the recently relit main roads in Southampton have Philips Luma 1s, which with their maximum LED configuration run at 180W. These are mounted on columns which could have potentially had 140W CosmoPolis lamps fitted, which have a lower circuit wattage than 180W. Or another example, the Highways Agency replaced some Philips MA60s, 180W SOX with a circuit wattage of about 230W, with Luma 3s, maximum LED configuration with a power consumption of 446W. The new lighting is very good, but then again it should be at nearly double the power consumption!