LED Luminaries

LED news and insight from our technology editor Steve Bush, who has been messing with LED lighting for more years than he would care to remember.

Is it really that eco friendly?

When designing products these days, designers have to be very conscious of their choices in regards to materials and processes used for manufacture. A lot of people assume that a products impact on the environment is only relevant when the product is in use. However, products which can be relatively eco friendly to run, such as the Hybrid cars, can be very un-eco friendly to manufacture and dispose of.

This can be down to a number of things:

  • Materials chosen.
  • Manufacturing processes.
  • Transport.
  • Number of components.

Manufacturers have become very aware of this, and, some, are required by law to conduct an LCA study (Life Cycle Analysis). This is when a manufacturer, for example a fridge manufacturer, must look into how their product affects the environment throughout it’s life time.

The reason I think this is relevant to LEDs is because, eco friendly lighting seems very focused on how much energy the bulbs use when used by the consumer. If we look at the general construction of an LED bulb we can assess it’s environmental impact in comparison to other bulbs.

Parts: Heatsink, Lens, LED, Wiring housing, pins, screws
Materials: Aluminium, PVC, PC
Disassemblable : Yes

The negatives with the LED is that there are a large number of components, which will take up manufacturing energy. However, these are disassemblable so can be disposed of individually. If we look at the main use of material for the LED, the heatsink, we can focus this topic more.

Aluminium is the most abundant metal in the earth’s core, it also has a low melting point in comparison to other metals and can be cast (which is the lowest carbon emitting process used to form metals). For the amount of time that LED bulbs last, the production energy of the components divided by the years of use probably works out to be very low per year, add that to the amount of energy LED bulbs use in their life time and you have a very eco friendly product.

LED is the supposedly the more eco friendly option to CFL bulbs. As I’m sure many of you are aware, CFL bulbs contain mercury gas. The problem with this is the large environmental hazard they pose when being disposed of. Compact fluorescents also use up a large amount of energy when first starting up, which, when being used for short periods of light, makes them not environmentally friendly at all.

What I am really interested in, is whether LED is still more environmentally friendly when it comes to big Wattages. As I mentioned in a previous article, LED’s require heatsinks to disperse the heat they create. The higher the wattage, the higher the surface area needed to disperse the heat. My question is, is it more environmentally friendly to use CFL when higher Wattages are required?

LED and CFL give off, roughly, the same amount of lumens per Watt. However, if the LED needs a very large heatsink to compete with the light output of the CFL bulb. Does the production energy used to create the LEDs heatsink outweigh the start of energy and impact of the Mercury in the CFL when it is disposed of? I believe more research needs to be done on this to decide whether LED should be developed to produce higher Wattages, or just reserved for lower levels of light.

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8 Comments

  1. GeorgeTheGeologist
    February 03, 2009 10:58

    “Aluminium is the most abundant metal in the earth’s core”
    sp. “Earth’s crust”.
    The core is mostly iron, and irrelevant since it is, in all practical senses, inaccessible.

  2. John Catchpole
    January 29, 2009 19:34

    An Aluminium heat sink does not have to be disposed of if it is part of the fitting and not the lamp. The efficiency’s we are using now are greater than CFls and are still increasing. As more of the energy gets converted to light, which is radiated, so there is less residule heat left in the fitting. We are seeing this within designs at the moment where the fitting is cooler than we had calculated and allowed for.

  3. Oliver Sowerby
    January 29, 2009 15:48

    Aluminium does require energy to take it from where it is found. But to produce any material you require energy to do so. The important questions is: Which materials use the most?
    This is just one factor of what makes a product more Eco friendly. For example aluminium could use more energy in this respect, but the forming of it may use less energy than materials which are more easily obtained.
    Maybe the start up energy of CFLs is not amazingly high, but they still have a period where they are using energy before they are giving out their maximum amount of lumens, which is more than what LED does.

  4. R Hart
    January 29, 2009 15:38

    You say that “Aluminum is the most abundant metal in the earth’s core” but it takes a large amount of electricity to release it from ore and this must be taken into account. Also the reason why the CFL is more efficient in eco bulbs is that there is a raising of frequency from 50Hz to many kHz and so the choke necessary to start the bulb becomes smaller and of lower resistance and so looses less energy. Because it is small and therefore cannot dissipate much energy the startup energy cannot be that great otherwise it would burn, so I doubt if there is much energy used in that initial start pulse, certainly less than the equivalent incandescent bulb.

  5. E Wagner
    January 26, 2009 15:20

    Actually that “fifteen fold” bit can’t be right as CFLs are not that much more efficient. Sorry about brain being only half engaged!

  6. E Wagner
    January 26, 2009 14:59

    The biggest human activity based release of mercury into the environment (volcanic activity is the natural big one) is from the burning of coal to generate electricity. The energy savings that result from using a CFL reduce the amount of mercury emitted many times more (I seem to remember five to fifteen-fold) than the few milligrammes of mercury in each CFL. Of course we should work to reduce CFL mercury content further but since a substantial proportion of electricty generation is coal fired and likely to remain so for decades to come the energy efficiency of CFLs is of great benefit and the mercury issue kept in proportion.

  7. Oliver Sowerby
    January 26, 2009 10:52

    CFL does produce light as soon as it is switched on. However, it does not produce light to it’s full capability until a considerable amount of time after wards.
    It is also uses up a large amount of energy to get from the initial light to the maximum light output.

  8. January 26, 2009 10:44

    Does CFL really use “large amounts of energy” when first starting up?
    They start in about 1 second so for that energy to be significant over a few minutes they would have to have a very high start up current indeed.

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