Consumable light

Imagine that after all the talk and hype, scientists and engineers finally came up with affordable LED lighting solutions which cost less to use even than compact fluorescent  light bulbs. This could actually happen within 5 years. But imagine it were true now! Wow! What would happen?

  • Would we simply use the same amount of light and pocket substantial savings in cash, energy and carbon?
  • Would we revel in the technology and – since it was now so cheap – find new ways to consume more light (and electricity and carbon)?
  • Would the third world – in which people spend many evening hours in near darkness – consume more light?

These questions were addressed in a recent scientific paper (which seems to be free to download for the moment!) and the analysis really moved me. Of course no one knows what technology will actually become available. Or when. Or at what cost. And no one knows how these technology developments will interact with human society worldwide. But the paper considers a wide variety of possible scenarios. Reading the paper I was struck again and again by the straightforwardness and thoroughness of their analysis, and the contrast between the sophistication of their analysis, and the naivite of my own prior thoughts on the matter. It’s a long paper and quite technical, but there are two things I would like to comment on: the concept of light consumption, and my own technological utopianism.

Light consumption

I had never thought of light itself as a product, but of course in can be thought of that way. A lumen is the unit used to measure the amount of useful emitted by a light bulb. It is a product of the amount of amount of light of all frequencies (colours) emitted, and the sensitivity of the human eye to those colours. Although we are not usually aware of it, when we are buying light bulbs we are actually seeking devices to produce (consume) a certain number of lumens of light in our homes. By quantifying this consumption, and charting historical ‘consumption’ over several centuries, the authors can make plausible estimate for how consumption might change  as new technologies become available.

Technological Utopianism

The most profound effect of the paper was to puncture my sense that improved light technology would some how ‘solve a problem’. It had seemed so obvious to me that LED lighting would reduce the carbon costing of lighting and thus reduce the carbon emissions associated with lighting. I had been aware of the problem that if I saved (say £100) on my electricity bill, I would use that £100 to consume some other resource – which would have a carbon cost associated with it. But I had not really considered the effects on the third world – which would ‘consume lumens’ voraciously if they were cheap enough – and the effects of the market to develop new ways in which we could ‘consume lumens’ – mood sensitive lights or uniformly illuminated floors and walls – or whatever our collective imagination comes up with. In short, if a perfect lighting technology – and LED lighting is very nearly that – became available it would not definitively solve any societal problems.

The growth in LED lighting still seems inevitable – and I still hope it will happen. Allowing large swathes of the third world to function in the evening will bring enormous benefits. And reducing energy (carbon) consumption in ‘lumen saturated’ societies such as our own is definitely a ‘good thing’. But the problem of carbon emissions that we face collectively is unlikely to be solved by a technological fix. I feel like I have just become a technological realist.


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2 Responses to “Consumable light”

  1. Progress in lighting « Protons for Breakfast Blog Says:

    […] per watt. This change is critical to driving people towards more efficient lighting technologies. As I mentioned last week, this won’t save the world, but it will save at a least save a little […]

  2. protonsforbreakfast Says:

    This afternoon, I spotted some lights left on in a corridor in a refurbished module at NPL. I went in to switch them off, but I couldn’t find the switch. After a little search I realised the switch has been covered up and there was no light switch! Looking up I realised the new lights were LEDs, and either they consumed so little energy that they had been permanently wired on, or alternatively (and more probably) they were being controlled remotely. The problem was, there was no need to have them on at all!

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