Welcome to the compact fluorescent twilight zone

When does it not make environmental sense to switch from incandescent lightbulbs to CFLs?

Published March 21, 2008 10:12PM (EDT)

You are traveling through another dimension -- a dimension not only of sight and sound but of mind.

That's how How the World Works feels after striving to parse the implications of an article that adds new complexity to the ever popular debate over which is better: compact fluorescent or incandescent lightbulbs.

Followers of the story so far know that incandescent bulbs convert as little as five or ten percent of the electricity they consume into actual light. The rest is "wasted" as heat. Not so for the far more energy-efficient compact fluorescents. Score one for CFLs.

But what if you need that heat to keep warm?

Citing calculations from a new Canadian study, "To Switch or Not to Switch: A Critical Analysis of Canada's Ban on Incandescent Light Bulbs," columnist Tyler Hamilton proposes that whether or not it makes sense to switch from incandescents to compact fluorescents -- during a cold winter -- depends on the source of electricity that powers the local grid.

Here's where it gets a little confusing. If your local grid uses renewable energy, (as in the case of hydropower-rich Manitoba and Quebec) then you shouldn't switch to CFLs. The rationale for this is that if you did switch, you would then have to replace the heat previously generated by incandescent lightbulbs with heat generated by fossil fuels such as natural gas or heating oil. So if you switched to CFLs you might end up consuming more fossil fuel and generating more greenhouse gases than if stayed pat with incandescents.

However -- if your electricity and heat are both generated from fossil fuels, CFLs are recommended, because, says Hamilton, it is more efficient to burn natural gas directly for heat than to burn it for electricity which is then converted to heat via incandescent lightbulbs.

"To Switch or Not to Switch" does not appear to be available online, so it's hard to get a sense of how rigorous the argument is. It's not at all clear to me how much heat is provided by lightbulbs compared to, say, the gas heater. And the calculus varies considerably if you move from the frozen tundra down to, say, California's Great Central Valley during the summertime. In that scenario, the heat from lightbulbs only adds to the load of your air conditioner -- no matter what is fueling the grid.

In every scenario, a different solution. The 21st century could turn out to be hard for absolutists.

By Andrew Leonard

Andrew Leonard is a staff writer at Salon. On Twitter, @koxinga21.

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