efficiently lit

This rant is inspired by a recent post about home heating using a heat exchanger technology. The main point was, when use this style of heating, it is actually better energy conservation practice to leave your thermostat at a constant temperature rather than turn it down at night (as would have been appropriate with a furnace heating system).

At the start of this year our provincial government issued an edict prohibiting retailers from stocking 75 W and 100 W incandescent bulbs. The argument generally goes that incandescent are “less efficient” and some millions of dollars in electricity could be saved if we all switched to compact fluorescent (CF) bulbs, therefore ban incandescents.

I’ll put my conclusion first, that way you can stop reading now if you want. I think banning incandescent bulbs is preposterous and ill thought out. They are well suited to many applications and CF bulbs are poorly suited to several environments and contexts. Now I begin my rant.

First, here are some typical numbers used to back up the “efficiency” argument.

Replace a 60 W incandescent lamp with a 12 W compact fluorescent (16 W including ballast) for 1 year at $0.08/kWh [source].

24 hours/day operation
525 kWh 140 kWh
$50.81 $19.09
8 hours/day operation
175 kWh 47 kWh
$16.93 $6.37

The example suggests a monetary payback in 2.5 years for a bulb on 8 hours per day (including bulb costs).

How about energy consumption? If we include manufacturing and recycling energy costs we can shift to a more cradle-to-grave or dust-to-dust perspective. One analysis suggests that a compact flourescent will give an energy payback at around its 50th hour of operation. That is pretty quick!

Now it is time to look at the externalities.

The externalities that come to mind immediately are: mercury, home usage scenarios, human factors, and “waste” energy.

CF bulbs contain about 5 mg of mercury. This has been well discussed and the unanimous conclusion is that enough mercury is emitted during the extra electricity production to power an incadescent bulb that there is a dramatic payback. My problem here is that all the comparisons are done using coal burning power plants. Most electricity production in BC is hydroelectric. How does the comparison hold up if we consider the combustion of oil or shale gas? I remain unconvinced that this externality has been adequately addressed for a context that does not rely on coal as a primary source of power.

CF bulbs are ill suited to many common household usages. For instance, their lifespan is dramatically reduced if they are regularly turned on and off or attached to a dimmer. According to BC hydro, using a dimmer with a CF bulb can actually cause it to break! I have had one of these explode on me. The official line is to “open the window” for fifteen minutes in order to let the mercury disperse. Additionally, the bulbs are much dimmer when used in a cold place. This suggests they may be a poor choice for a porch light, garage, or shed.

In order to keep the concentrated 5 mg of mercury out of our lives once a CF bulb has expired (assuming it did not break open), it must now be properly recycled. Both home depot and ikea will accept CF’s for recycling but outside a major city those can be hard to find. Even in a town with one of those two retailers, how many people are ready to cart their hazardous waste out to a specific store they have no other reason to visit? There are serious barriers to proper disposal.

Finally, the one that grinds my teeth the most. What becomes of the energy “wasted” by incandescent bulbs? It becomes heat. A highly localized electric heater in a room that typically has a person in it. I certainly grant that there are more “efficient” ways to heat a home than by electric filament but, in a BC context (and probably a national Canadian context), this heat is rarely a waste.

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1 Response to efficiently lit

  1. gai says:

    interesting analysis, Kaan. I knew about most of your points, but opening a window to disperse mercury from a broken bulb is ludicrous.
    Just today I tried to recycle 3 CFLs at the Gibsons recycling depot. Two of them never did work, and I can’t be bothered to find the original receipt to return them to the store. The depot wanted $.25 ea to recycle. This is ridiculous.

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