Coal, mercury, and CFLs

2009-09-08

in Economics, Politics, The environment

Those concerned about the mercury in compact fluorescent light bulbs should consider what the primary source of mercury contamination in North America is: coal-fired power plants. A report prepared earlier this year expects mercury levels in the Pacific to double by 2050, as the result of emissions from new coal plants.

This is especially relevant in places where summers are hot, since we might be paying a double climate and mercury price for the heat being produced by incandescent bulbs. If air conditioning is being used to get rid of it, the bulbs may well have negative efficiency in addition to their role in poisoning water supplies through those coal plant emissions.

All this is yet another reason why coal is the enemy of the human race.

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{ 5 comments… read them below or add one }

R.K. September 9, 2009 at 11:50 am

This is one reason why ‘clean coal’ is such an absurd phrase. Even if they bury the carbon, there are still lots of other nasty things introduced into the environment when mining and burning coal.

Tris September 9, 2009 at 2:08 pm

My concern with mercury in these bulbs is the risk of personal exposure, not overall mercury contamination.

Milan September 9, 2009 at 2:13 pm

Fair enough, though it is pretty shocking that the USGS report released earlier this year projected that coal-fired power plants would increase the amount of mercury in the entire Pacific Ocean by 50% on the next 41 years.

The increase in edible fish will presumably be even more, since mercury bioaccumulates.

Even with CCS, ‘clean coal’ is a contradiction.

. March 24, 2010 at 2:31 pm

“The Natural Resources Defense Council says it has taken a close look at the safety of C.F.L.’s and believes they are the “clear choice for everyone concerned about protecting their health and saving energy.”

According to the council, an average compact fluorescent bulb contains five milligrams of mercury, which is roughly equivalent to the size of the tip of a ballpoint pen. By comparison, the group notes, there is “between 60 to 200 times that amount of mercury in a single silver dental filling in people’s mouths, depending on the size of the amalgam.”

Those with concerns about mercury exposure, however, often refer to the results of a Maine Department of Environmental Protection study, which found that mercury levels in excess of the amount the state considers to be of a minimal health risk can occur when a C.F.L. breaks.

The report also concludes that mercury can remain in carpeting and other flooring surfaces even after clean up, something the report said was of “particular significance” for children rolling around on the floor and crawling babies.

“It is unclear what the exact health risks are from exposure to low levels of elemental mercury, especially for sensitive populations,” the report states, “so advising for the careful handling and thoughtful placement of C.F.L.’s may be important.”

Providing yet another view on the matter, lighting scientists from Lawrence Berkeley National Laboratory wrote an essay, “Dangerous Mercury in C.F.L.’s? One Big Fish Story.” In it, they said “the most extreme C.F.L. breakage scenario” measured in the Maine study “only equaled the approximate exposure from a single meal of fish.”

“If simple common sense is used in disposing of the broken C.F.L., the resulting exposure to mercury is equivalent to about 1/50th of an ounce— a single nibble — of Albacore tuna!” the scientists added.”

. July 2, 2013 at 2:25 pm

Not that there is anything wrong with the old sodium-discharge lamps. Producing practically all their light at a wavelength near the peak sensitivity of the human eye gave them a theoretical luminous efficacy of 200 lumens per watt of electricity consumed, though their real-world performance is around two-thirds that. The new white LEDs used in his street are rated at around 100 lumens per watt. Compact fluorescent lights (CFLs) used in the home produce 60 lumens per watt, while traditional incandescent bulbs emit a miserly 15 or so. In terms of energy savings, then, LED streetlights are contenders but not champs. But they have other advantages. One is longevity: they simply do not burn out, but gradually lose their brightness over the years.

It turns out that white LED lamps do a better job of meeting these conflicting requirements than sodium lamps can manage—and they do it at lower power levels, to boot. There could therefore be some energy savings from switching to LED streetlights after all.

Although some of the latest incandescent bulbs could more than meet the new efficiency standard, traditional tungsten-filament bulbs did not stand a chance. Meanwhile, CFLs had begun to acquire a poor reputation. Few lived up to their claim of longer life, especially when they were switched on and off repeatedly, or used in recessed ceiling lights where heat could build up and fry their circuitry. And though LED bulbs have a total-cost-of-ownership significantly less than that of sodium or other forms of industrial lighting, and have proved their worth to municipalities and businesses, they have yet to do the same for residential users.

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