Mercury, CFLs, and the Environment

Alice La Pierre
Tuesday October 08, 2002

Recently a Berkeley resident expressed concern to us that the compact fluorescent lamp (CFL) that she wanted to install to save energy had mercury in it, and this mercury would do more to harm the environment than the incandescent lamp she would replace. (Mercury is used in all fluorescent lamps to start them.) 

While it is true that fluorescent lamps have a very, very small amount of mercury in them (about 1/1000th of an ounce – smaller than the period at the end of this sentence), a regular incandescent light bulb actually releases much more mercury into the environment.  

The biggest source of mercury contamination is the mercury released through coal-fired power plants. Emissions from coal-fired power plants release approximately 46,300 kilograms of methylmercury a year, according to the EPA. CFLs use less energy and therefore reduce mercury emissions from coal plants. Replacing 1 billion incandescent lamps in the U.S. with CFLs could reduce mercury emissions by nearly 10 million grams. 

How can a light switched on in Berkeley affect a coal-burning power plant in Arizona? Berkeley’s power grid is connected to the national electrical grid. The flip of a switch here calls on all power plants, including coal plants, to produce more power to supply the grid. 

Over the life of one 27-watt CFL (about 10,000 hours of operation) it will consume 270 kWh (costing you about $40), resulting in a total of 8 mg mercury (~4mg from the bulb and ~4 mg from electricity production – half of this mercury is contained safely inside the lamp). Over that same 10,000 hours, a 100-watt incandescent bulb will consume 1,000 kWh (costing you about $150 for energy – and you will need to buy ten of these, since they only last about 1,000 hours each). A portion of that energy will be generated from coal which will release 17.6 mg mercury over hundreds of square miles.  

Coal is the major fossil fuel used to generate electricity, in both the eastern and western United States. (The US fuel mix for electricity production is 56 percent coal, 9 percent natural gas, 4 percent oil, and 31 percent non-fossil fuels – hydroelectric, geothermal, solar, wind and cogeneration.) The smokestacks of these coal-burning power plants release “chemical vapors (of) known carcinogens such as mercury, heavy metals (arsenic, beryllium, cadmium, nickel), dioxin, furans and PCBs,” according to environmental coalition Power Scorecard TM. An inventory of mercury emissions conducted by EPA in 1993 found that one-third of all mercury air emissions comes from coal burning electric power plants.  

The mercury from smokestacks becomes airborne, spreading over hundreds, even thousands of miles before being deposited into waterways, pastureland and soil. Cows or cattle on pastureland hundreds of miles away take in mercury and heavy metals while grazing.  

In the water, mercury can be absorbed  

by anything from plankton to whales. Mercury is a bioaccumulator, meaning that it is deposited and retained in the fatty tissues of animals, including humans, and excreted very slowly. The higher up on the food chain you eat, the more likely it is that you will intake some amount of mercury. Methylmercury accumulates appreciably in fish. Tuna and swordfish are well known incubators of mercury.  

Mercury is linked with a number of serious health problems, including both neurological and developmental problems in humans. The EPA has issued warnings for pregnant women and young children against eating more than two servings of tuna or swordfish per week. According to the EPA, “children born of women exposed to relatively high levels of methylmercury during pregnancy have exhibited a variety of developmental neurological abnormalities, including delayed onset of walking and talking, cerebral palsy, and reduced neurological test scores. Far lower exposures during pregnancy have resulted in delays and deficits in learning abilities in the children.”  

Replacing your incandescent bulbs with CFLs will not only reduce the release of toxins into the environment, it will lower the lighting portion of your electric bill by ~75%. If you replace twenty 75-watt incandescent bulbs with 20-watt CFLs, you would save 1,100 watts for every hour that the lamps burned. At five hours per day per lamp, this would mean over 2,000 kWh, or about $300 back in your pocket every year. 

A new type of CFL- Cold Cathode Fluorescent Light (CCFL) – is being developed. CCFL’s bulbs are even more efficient, produce less heat, and are smaller and more compact. They are also projected to last much longer than conventional CFL’s bulbs and ballasts. CCFLs may be available for sale in the near future. 

Compact fluorescent lamps can be purchased in a variety of places, and at reasonable prices. The Ecology Center and Berkeley Farmer’s Markets sell them for between $5 and $7 each through the Berkeley Conservation and Energy (BC&E) program. Some CFLs on the market still have magnetic ballasts, meaning that they will flicker. Look for good-quality lamps that have the Department of Energy’s “EnergyStar” logo on them to assure good color and an electronic ballast, which produces an even light with no flicker. (This is what the Ecology Center carries.) As for wattage, you should replace an existing incandescent bulb with a CFL with approximately _ the wattage to maintain the same light levels. So, a 60-watt bulb can be replaced by a 15-watt CFL; a 75-watt by a 20-watt CFL, etc. 

And when it comes time to recycle that CFL, contact the Alameda County Household Hazardous Waste Program, located at 2100 East 7th St., Oakland (west of the freeway). Call 670-6460 for current operating hours. 


For more information, visit the Energy Office’s website at www.ci.berkeley.ca.us/ENERGY or email energy@ci.berkeley.ca.us 


Clarification: In response to the last PowerPlay column regarding Berkeley’s Residential Energy Conservation Ordinance (RECO), we’ve received a number of questions about the origins of the ordinance. It was enacted 25 years ago in 1987, and has succeeded in helping to reduce home energy expenses for Berkeley residents. In the past five years alone, more than 5,000 homes underwent RECO improvements, saving the average homeowner about $450 per year in energy costs.