A key part of self sufficiency around the homestead is energy independence and minimizing your reliance on commercial power supplies. The first step in any alternative energy (AE) program is conservation of the energy you are already using. Lighting is a huge percentage of our electrical consumption. 38% on average. Compact Fluorescent Lights (CFLs) are one solution to reducing this number. There have been several concerns raised about the presence of mercury in these devices, and while I don’t want to dismiss them as invalid, a bit of digging into the facts certainly minimizes the impact of them in the big picture. They are not the end solution to our lighting needs, but they are clearly a step in the right direction in my mind.
A typical CFL in use contains about 3.9 mg of mercury(Hg). Recent advances and goals set by National Electrical Manufacturers Association(NEMA), the average Hg content in CFLs has dropped at least 20 percent in the past year(2008). The best, and most expensive lamps, have made further reductions, dropping mercury content to 1.4 – 2.5 milligrams per light bulb.
In the US about 100 MT of mercury are released each year, primarily from coal fired power plants. Most mercury in a CFL is bound into the glass as the product is used. Estimates place the free mercury available for contamination at 11% of initial content for a lamp that is used for its rated lifetime. NEMA reports about 300 million CFLs sold in 2007. If all of these are sent to the landfill and broken open and the mercury scattered for rapid dispersal into the water table (a worst case scenario considering containment and recycling), this would result in 0.15 MT of Hg.
Now consider the mercury output per kW hour for electricity use. 0.012 mg Hg/kW hr is a safe number for coal fired mercury emissions. Multiply this by the 8000 hour lifetime estimate for a 13 W CFL. That is a 1.2 mg mercury emission over the life of the lamp. Add that to the 4 mg in the lamp itself and that is a ceiling of 5.2 mg. Now consider the kW hours of an equivalent 60 W incandescent lamp. Do the math and you end up with 5.8 mg. That is all worst case. Remember that mercury content in the CFLs is dropping, not all if the mercury is available for release into the environment, and that energy needed to make the 4-8 incandescents vs. the single CFL, a fair estimate would be 1.6 total Hg from the CFL vs 5.8 from the incandescent.
In the interest of presenting both sides…
- If you live in an area served primarily by Hydro, Solar, Nuclear, or Geothermal electrical energy this argument doesn’t apply. Hydroelectric power obviously doesn’t release any mercury into the atmosphere as it drops over the ledge of a waterfall.
- I don’t know about other possible contaminants that may or may not be released as part of the manufacturing process in CFLs vs. Incandescent. It is possible that the manufacturing process for CFLs is a nasty affair.
- Recycling helps both sides of the coin!
As always there are several things you can do to reduce you lighting electrical demand regardless of your light source:
- Turn off all lights when you’re not using them.
- Consider reducing your lighting energy use in areas of your home that receive plenty of natural light.
- For tasks where you need more concentrated light, such as reading in the living room or working at your desk, rely on localized lamps rather than general room lighting.
- Consider performing tasks needing a lot of light when natural light is available.
- Encourage your friends and family to do the same.
Remember it’s all about simple steps. Take a few here and there to help regain your independence.
