Making choices about the kind of light bulbs we should be using, on the simple basis of energy consumption, and hence carbon emissions, may be a little short-sighted. Thus, the old fashioned incandescent bulbs are no longer commonly on sale, though there is something of a black market in them, due to the poorer quality of light given out by their alternatives - low-power CFLs (compact fluorescent light bulbs) and LEDs (light emitting diodes).
The first incandescent (filament) bulb was invented by Joseph Swan, who gave the first public demonstration of the device at a lecture in Newcastle upon Tyne, in the north east of England, on 18 December 1878. Swan later illuminated his house, in neighbouring Gateshead, by means of the technology. Credit for the incandescent bulb is often, but incorrectly, given to Thomas Edison, who invented it independently, but later than Swan. In 1881, the Savoy Theatre in London was lit by Swan incandescent light bulbs; the first theatre and the first public building in the world to be lit entirely by electrical power. The basic principle of the incandescent bulb has changed little in the past 135 years, of which the main criticism is that most of the energy consumed by the bulb is discarded as heat, rather than providing useful light.
Despite the wide, and almost exclusive, adoption of CFLs and LEDs in place of the original design, a life-cycle analysis http://pubs.acs.org/doi/abs/10.1021/es302886m has shown that there may be an environmental legacy, beyond carbon emissions, or their reduction, in the form of toxic metals, especially copper, lead, mercury and zinc, with smaller amounts of arsenic and antimony, which needs to be given greater consideration. The analysis accounts both for the metals that are present and their expected lifetimes in the environment, and concludes that both CFLs and LEDs should be classified as hazardous waste, in particular because of their lead content, which can be leached at 132 and 44 mg/l, respectively, and well above the accepted threshold of 5mg/l.. The amount of copper is also at issue, being 111,000 and 31,600 mg/kg respectively, in comparison with the accepted limit of 2500 mg/kg.
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In their favour, both devices last far longer and consume considerably less power than do incandescent bulbs; nonetheless, the presence of heavy metals is concluded to impart some 3 -- 26 times the environmental burden for CFLs, while LEDs are deemed to be worse overall by a factor of 2 -- 3 than their more established counterpart. It is concluded that not only must energy consumption be taken into account, but that a reduction in the levels of toxic materials incurred in the manufacture of such "green" technology should be factored in to the design.
These results represent an alternative reality, in terms of our use of materials, since they tacitly illustrate the point that the final disposal/reuse of materials used in the manufacture of all appliances and devices must be designed-in to the processes through which they are created. The supply of various elements is at issue, and efficient means for recycling them is the only way to avoid running out of, e.g. indium, helium, and many other vital materials within only a decade or so http://ergobalance.blogspot.co.uk/2012/07/shortage-of-resources-for-renewable.html. The notion of the circular economy http://en.wikipedia.org/wiki/Circular_economy is the overarching example of this line of thinking, which follows the patterns of Nature, in which there is no such thing as "waste". Everything in the natural world is recycled, e.g. though such processes as the soil food web, providing energy and materials among an holistically interacting community of organisms, at a population of billions in a teaspoonful of soil http://en.wikipedia.org/wiki/Soil_food_web.
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In principle, we can reuse materials to fabricate new and replacement technology, so long as we have sufficient available energy to do this. It is the loss of cheap energy, particularly in the form of liquid fuels refined from petroleum, that will set an ultimate limit to the extent by which human civilization is underpinned by technology. When this begins to fail, we may nonetheless draw from the design models of nature, in adopting lower energy, intermediate technology paradigms, such as are found in the principles of permaculture http://www.permaculture.org.uk/. Hence the environmental problems accorded from low energy light bulbs, and carbon emissions, will no longer be a feature for us, once we have become reconnected with the natural world.
By. Professor Chris Rhodes