AskPablo: Mercury in Compact Flourescent Bulbs

cfl_curled.jpgWell, another week is here, another weekend is gone, and it’s time for another installment of AskPablo. I hope that some of you got a chance to see the West Coast Green Conference/Expo. Let me know if you had any suitable AskPablo questions come up. This week we will be looking at another comparison between two alternatives: incandescent and compact fluorescent light bulbs (CFLs). Last year someone raised the point that CFLs contain mercury and asked me to justify his purchase of them. Do you really want the answer? Enter if you dare.

Well, it’s true. According to the United States Environmental Protection Agency CFLs contain around 4mg of mercury. By comparison, older household thermostats contain about 3000mg (trade them in for programmable thermostats now!), and thermometers contain around 500mg (digital replacements available, make sure you properly recycle your old ones). So, 4mg is not much in comparison to other mercury-containing household items but mercury is bad stuff, in any concentration. So how much mercury does an incandescent bulb contain? Well, I’m sure there are trace amounts in the glass, metal, or solder that holds them together but I haven’t been able to find any data one this so we will assume that the amount is negligible. Debate over? Not so fast!
Both bulbs require electricity. An incandescent bulb requires about 4x more energy to illuminate the same space, so we have something to go on. It turns out that coal-fired power plants emit mercury. Surprise! Let’s see how much. Over 5 years (the life of a CFL) it may be responsible for 2.4mg of smokestack mercury emissions, so a total of 6.4mg of mercury over the life of the bulb. By comparison the incandescent bulb is responsible for almost 10mg of mercury emissions over 5 years. But CFLs can be recycled to recapture the mercury. Smokestack emissions can not be recaptured after they enter the atmosphere. So, if we want to, we could probably deduct the mercury contained within the CFL bulbs from the equation. Therefore incandescent bulbs are responsible for around 4x more mercury emissions than CFLs.
In case you don’t hate incandescent bulbs enough I have a quite overview of their wastefulness… Power plants convert fuel energy into electricity at about 30% efficiency, so one hundred units of fuel make only 30 units of electricity. Deduct for this the line losses that occur from transmission lines and other losses in converting high voltage to low voltage and we end up at around 20 units of electricity. A large part of the energy used by incandescent bulbs goes into making heat (just like my damn laptop computer), leaving around 1-2 units of energy of actual light energy. You would think that we could do better than 1-2% efficiency, wouldn’t you? Well, we can. Install CFLs everywhere, support distributed generation through renewable energy sources and natural gas cogeneration microturbines, install occupancy sensors, turn lights off when you don’t need them, replace your halogen upright lamps with fluorescent uprights, etc.
See you next week!

22 responses

  1. Since both types of bulbs experience a decrease in longevity if toggled frequently I don’t think it matters much. The CFL will still last much longer than an incandescent and will still use 1/4 the electricity.

  2. I have a question. Have you looked at the difference between air travel and car travel before? Assuming you are using regular gasoline and not ethanol what would be best for crossing the country, or half way across the country?

  3. I’m almost coninced. But in’t mercury emitted into the air going to be much more widely diffused and hence ingested by animals/plants/other things at much lower levels than mercury from a broken energy efficient light bulb?

  4. Donald,
    There are three ways to deal with pollution: 1)Dillution, 2)Concentration and Disposal, 3)Avoidance. Power plant emission take mercury that is naturally present in coal and disperse it into the atmosphere. The problem with this sort of dillution is that it adds up over time. And since organizms can’t metabolize mercury it gets passed up the food chain and concentrated in those at the top, us. CF bulbs contain the mercury in a concentrated manner, allowing us to recapture it after its useful life is over and finding new uses for it. The best solution, of course is avoiding the need for either type of lighting. I am sitting in a completely day-lit room right now which requires no mercury.
    Thanks for asking Pablo!

  5. Has anyone looked into how much energy it takes to manufacture a CFL versus a incandescent bulb? And the equipment used in their manufacture? I read CFLs need special equipment to make them in the shapes they are in.

  6. What about those of us who get headaches, red irritated eyes, mild weakness and irritability from CFL use? I had replaced incandescent bulbs a couple of years ago to save me the time of constant bulb replenishment. Had to go back to incandescent bulbs because I am just too sensitive to something in the CFLs bulbs. Are there any studies on this health phenomenen?

  7. Here’s a short critique of the bogus argument that there will be a reduction in toxic mercury into the environment with CFL’s due to the energy reduction from coal plants.
    (1) The old EPA figures most often cited are incorrect for several reasons. The basic one is that they assume 100% of electricity in the US is from coal plants. Not true. 50% of electricity does not come from coal plants in the US and coal plants are now being mandated to reduce their mercury emissions by between 70% and 90% over the next several years. The most recent calculations from the DOE indicate that, on the average, CFL’s are worse than incandescent bulbs in terms of mercury.
    (2) Places like California produce little energy from coal plants, and several states produce none. So any CFL energy reductions will not cut much, if any, mercury there.
    (3) The 5mg of mercury generally claimed for CFL’s is largely a goal and not the current reality which is as much as 600% higher for some major manufacturers according to suppliers of CFL’s to the State of New Jersey. All but one of the CFL’s offered had more than 5mg.
    (4) CFL’s are almost all made in China with energy from mostly very dirty coal plants that emit ten times the amount of mercury per KWH as US coal plants emit. Since China gets about 80% from coal and the US only about 50%, the comparison is much worse. Also, it likely takes the equivalent of up to 25% of the CFL’s energy savings to produce them there including the extra energy for the packaging and shipping compared to incandescent bulbs which are almost all made here. That represents a lot more mercury per CFL. Since fuel and power in China emit up to twice as much CO2 as in the US, on average, there may go up to half the CO2 savings. And since places like California are twice as clean in terms of CO2 as the rest of the US, there may be only nominal CO2 savings realized from CFL’s in some states. The same holds for SO2 and the Nitrogen Oxides.
    (5) Partly due to the increasing demand for their CFL’s, China is one of the few places left on Earth that still mines specifically for new mercury. And it is unlikely that these mines would meet our environmental and safety standards. Industry estimates are that as much mercury is lost to the environment in the mining, processing and shipping of mercury there as is available for use. Similarly, to meet the increased demand from a massive CFL program in the US, China will need to construct many new manufacturing plants using dirty energy to build and requiring much more dirty power to operate. This in turn will contribute to the need for even more new dirty coal plants.
    (6) As much mercury is spilled into the environment in the manufacture of CFL’s in China as goes into the CFL’s according to recent statements from industry representatives.
    (7) CFL’s are delivered here on ships using bunker oil, the worst mercury and CO2 producer of the fuel oils. Not to mention all the other really bad heavy metals and toxics that it emits. Overall, it is 1,000 times dirtier than standard transportation fuel. Again, incandescent bulbs are still mostly made in the US in existing industrial facilities and shipped using cleaner standard fuel.
    (8) There is no recycling program in place or planned that could handle the number of CFL’s proposed. Only 2% of CFL’s are recycled. And after many years, even the industrial recycling programs only handle about 25% of fluorescent lights, with no verification of how much of the mercury is actually captured. Given the amount of mercury lost to the environment in the production of CFL’s in China, if ALL the mercury in the CFL’s was recycled, there would still be a significant increase in global mercury pollution due to the massive use of Chinese CFL’s in the US.
    (9) It is likely that if any major recycling program is set up, the CFL’s will be shipped back to China for reprocessing in newly built plants using dirty energy.
    (10) States like California are already becoming the recipients of pollution, including mercury, from China.
    Thus, when an objective and realistic global lifecycle analysis is made, it is clear that a massive CFL program will put a great deal of additional toxic mercury into the environment and very likely into our kid’s bodies. And the EPA says that a sixth of them already have too much mercury in them.

  8. CFLs are no good. They give off radiation and cause illness. Governments never really care about people. People need to take care of themselves and not rely on gov’t. Please everyone get a clue. The best option is to inform yourself and to have a choice, not a government-controlled ridiculous ban. Do not believe everything you see on TV. That information is all controlled.

  9. Why CFL mercury is worse than coal power mercury:

    I agree with Ed Kirshner’s comment above….

    CFL mercury is a much bigger problem.


    Coal power mercury was only ever a problem where untreated coal was used, and dominated

    Also, emissions can now easily be treated, with new injection and photochemical techniques as well as so-called scrubbers.

    Not only that, emissions will drastically fall in the next few years, as EPA themselves maintain:
    2005 decision, 90% power station mercury emission reduction by 2018, (phase 1 = 21% reduction by 2010, phase 2 = 69% further reduction by 2018) , confirmed early 2009 by new administrator Lisa Jackson.

    For more see

    In a nutshell:
    1. We know where the ever decreasing local coal power stations chimneys are and we can treat their emissions with ever increasing efficiency at lower costs.

    2. Compare that with billions of scattered broken lights on dump sites, when we do not know where the broken lights will be, and so we can’t do anything about them.

    (deposit-refund or free collection schemes would be a good idea, but have not prevented most CFLs in Europe being thrown away with other household waste)

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