Yeah, well, maybe, to Jevons and his Paradox

Jevons Paradox is that when we increase the efficiency of the use of a resource we might not actually see a reduction in the use of that resource. The greater efficiency might make the use of the resource cheaper per whatever it is we\’re getting from it and thus actually increase the use of the resource.

This isn\’t actually just greenie nuttery, it is possible for it to happen. However, as with almost every question in economics the true answer is \”it depends\”. Depends upon what?

Konrad highlights the critical point – whether demand for the good in question is elastic or inelastic – and suggests that the demand for electric power is relatively inelastic and therefore the demand for lighting is inelastic, hence reductions in the cost of lighting will not lead to more that proportionate increases in the quantity of lighting consumed.

Yup…so we don\’t actually know whether LED lightbulbs will reduce, increase or keep the same the amount of electricity we use in lighting.

We can make guesses, as above, based upon what we know about the elasticity of demand. Pretty good guesses, informed guesses, but guesses all the same.

For there\’s still something we don\’t know. Yes, we can calculate our elasticity from past prices and levels of usage, we can calculate present ones too. Well, pretty well, roughly, at least.

However, elasticities change dependent upon what range we\’re in.

Think of water for a moment. That first litre or two a day has one elasticity, we\’ll pay damn near anything to get it. When we\’ve got a few tens of gallons a day to a few hundreds of gallons a day it\’s entirely different. To the point that we usually don\’t bother metering it for we\’re aware that price has very little to do with how much of it we\’ll use. When we\’ve got a few thousand gallons a day coming through the house we\’ll actually pay someone to take it away: some nice young man with a pump to get it out of the basement.

So where are we with lighting? We can say that we\’re not at the hiring the young man with the pump stage yet (given the inability of such to get light out of our house this is useful) but we do know that that stage will be reached at some point.

The existence of people who wear sunglasses other than as a fashion statement proves that.

So, will LED bulbs reduce, keep the same or increase the amount of electricity used to create light? The answer is \”we dunno\”.

All we can do is try it and find out.

5 thoughts on “Yeah, well, maybe, to Jevons and his Paradox”

  1. Watch how people try to distort this into wanting to “ban” LEDs using the pretence of “saving the environment” from too much electricity, but in truth the anger is down to the frustration over seeing a lost opportunity to bully and drag us back to the dark ages – literally.

    LEDs are now dim-able and available in a range of warmer tones. EU ban on incandescents, pushing CFLs + Ban on Chinese imports = Osram rent seeking at our expense.

  2. There was a piece in, I think, The Times recently pointing out that each time we have reduced the cost of lighting – from candles to oil lamps, gas and electric lighting – we have gone for brighter lighting. It will be interesting to find out whether this trend continues. The piece says that many people found early gas lighting dazzling – about as bright as a 25W incandescent lamp.

  3. Since the efficiency gain over tungsten bulbs is of the order 30 to 1, I will be betting on less electricity being used to make more light. Maybe twice as much light, one-fifteenth the electricity.

  4. @JBM

    It was in the Economist dated 26 August, and there was a wonderful conclusion:

    “It is worth remembering that when gas lights replaced candles and oil lamps in the 19th century, some newspapers reported that they were “glaring” and “dazzling white”. In fact, a gas jet of the time gave off about as much light as a 25 watt incandescent bulb does today. To modern eyes, that is well on the dim side. So, for those who truly wish to reduce the amount of energy expended on lighting the answer may not be to ban old-fashioned incandescent bulbs, as is the current trend, but to make them compulsory.

  5. “So, will LED bulbs reduce, keep the same or increase the amount of electricity used to create light? The answer is “we dunno”.”
    hmm … the answer is not “dunno” – I can answer that, we will use less electricity.

    Light is already cheap, cost is not much of a consideration, so we won’t use much more just because it got cheaper.

    On the other hand, if trips to the moon are reduced in price one million fold there may indeed be an increase in travel to the moon of more than a millionfold. (current flow being 12 people per 40 years and falling). If 300,00 people per year visit the moon for a tenner (or whatever) a pop then Jevons paradox is observed.

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