Expert: LEDs could start replacing lightbulbs soon

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Not taking everything into account

The calculations on the energy-savings gained by switching to a more efficient light source never seems to take into account where the 95% wasted in a traditional light bulb goes.
The answer, of course, is that it's dissappated as heat in whatever environment we use it. If that environment needs heating, the energy savings could be as little as nothing, zero, niente. Take my house, for instance. I have electrical radiators regulated, of course, by thermostats. If I replace a 60W lightbulb with a device that produces the same amount of light from nothing, thus consuming 0W, the only effect would be that my radiators would need to cover for the missing heat contribution and consume 60W more energy (or, more correctly 60Wh/h). Yes, 60W, not 60W*95%, since all the energy the lightbulb consumes, except for what leaves the room as light, ie shines out the windows, end up contributing to the heating of the house. Total energy saving: zilch.

This assumes that the house needs heating, which is true about 5 months a year. When this assumption falls, the energy savings will be directly dependant on the efficiency of my light source.

My point here is that we cannot isolate one energy cost and assume the rest of the system is unaffected by changes. My example shows that energy preservation may not occur, but there could be cases where environment actually suffers by this switch. If, instead of electrical heating, I were to heat my house with, for instance, oil, this equation would end up hurting the environment, since most of the electricity here in Sweden is produced in ways that don't contribute to the green house effect ( nuclear and water power plants are the main production technology here ), using less electricity in the house means(again, during those months heating is needed ) I will be replacing the 'green house neutral' energy consumption with the burning of oil, thus making things worse rather than helping.

I'm not saying energy-efficient light sources isn't a good thing, but making assumptions on how much energy can be saved on a national level without taking side effects like these into account will leave us with very over-optimistic results that will, in the long run, hurt our credibility.

Posted by: avajadi   Posted on: 11/04/06 You are currently: a Guest | Members login | Terms of Use

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