The BBC recently ran an experiment to see if a team of cyclists could produce enough power to run a house. The message was a good one - to show just how much power is wasted in many small ways - such as leaving the fridge door open and turning on the oven long before it is needed. Rows of frenzied sweating cyclists communicated the message very well.
Sadly, they fell into the usual trap - that of skating over the science in order to communicate the desired message rather than the scientifically accurate one. The example here, which was the point which drove me to switch off - was when a presenter showed how a single light bulb could be used to roast a chicken. Placed in an insulated box with the light bulb and left for 90 minutes, the chicken was tender, juicy and very tempting when removed.
This was, we were told, a stark illustration of just how much heat is emitted by an incandescent light bulb. Now, that is of course true (try holding one*), but the experiment does not prove that. All it proves is that the bulb emits some heat. The temperature in the makeshift oven is simply a function of the balance between the heat emitted and the degree of insulation. It has to be said, they had a lot of very good insulation; a laptop could probably have worked just as well.
The error was then compounded when the presenter said that all that heat was being wasted and that we could reduce our energy bills by replacing them with low-energy bulbs. This is a clear, outstanding example of the most common fallacy of scientific interpretation - that of treating an open system as a closed one.
Yes, if we consider just the light bulb, then the power required to light the same area will be less with a low-energy bulb. However, most domestic light bulbs are in an (err...) domestic setting. Now, the "wasted" heat does not simply disappear merely because the BBC lables it as wasted. It has to go somewhere; it will heat the house in which it is fitted. So, if you replace it with a low-enery bulb then the house will be heated slightly less. Assume that the house is centrally heated (as most now are) and the fallacy becomes evident. The loss of the heat that was emitted by the light bulb will be replaced by an increased output from the central heating system - many of which are gas-powered.
So, our first conclusion is that by switching to low-energy bulbs, we move from the use of a potentially renewable energy source to the use of a non-renewable source. Ooops.
Our second conclusion is that if your aim is to present a specific view rather than merely think the situation through scientifically, it is easy to fall into a misleading fallacy - even without intended to misinterpret or manipulate. CRU, take note.
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(*if you're stupid enough....)
Now, the "wasted" heat does not simply disappear merely because the BBC lables it as wasted. It has to go somewhere; it will heat the house in which it is fitted...The loss of the heat that was emitted by the light bulb will be replaced by an increased output from the central heating system
ReplyDeleteAnd in the summer?
Actually I think this exposes you as a secret warmist. Your plan is to get us all using normal light bulbs in order that our houses may be heated by this unrecognized source, thereby (joining the CRU in) "hiding the decline" in real temperatures.
A good point re the summer [but have you been to Scotland? ;-)], although we will tend to use lightbulbs less then, and only as the day is cooling. Maybe* it is more efficient to take the edge off a May evening with a light bulb than to kick in the central heating for an extra week or two?
ReplyDelete(*haven't done the maths)
secret warmist
ROFL!
You make the very point I have been trying to make for a long while. Lights in the domestic setting are generally switched on as it becomes dark and generally as temperatures are falling. In the summer they "take the edge off" the chill, and in the winter merely reduce the heat output from the boiler. The only place worth using them is out of doors. And incidentally, no-one seems to have done an "end-to-end" evaluation of their greenness, but perhaps it doesn't matter if China produces an enormous carbon footprint as a result of their production, it reduces the footprint in the UK.
ReplyDeleteno-one seems to have done an "end-to-end" evaluation of their greenness
ReplyDeleteIndeed. As with most things, in fact. Toyota Prius, anyone?
perhaps it doesn't matter if China produces an enormous carbon footprint as a result of their production, it reduces the footprint in the UK.
Yes, there seems to be an insane notion that by impoverishing ourselves and exporting our economy elsewhere, the climate will benefit. Weird.
And to add evidence for the "Patently Hypothesis", might I say that at this moment, I currently sit in a room in Scotland, underneath an energy saving bulb, with a radiator (heated by the burning of oil) belching heat into the room, the temperature of which is currently 14°C. Every bit of warmth that might come from that light bulb, powered largely by hydro-electricity, is very welcome.
ReplyDeleteAnd here is another curious thing. In the days of incandescent bulbs, I was always careful to switch them off when leaving a room, because they used so much electricity. However, I am so convinced that energy saving ones use almost nothing that I cheerfully leave them on in empty rooms all day.