Making Up The Difference Pt. 3A: CFLs in Homes

Fluorescent light bulbs have always had a negative connotation, and even today many adults still cling to first impressions formed when the technology was not ready for prime time. This has held back the compact fluorescent light bulbs (CFLs) that today fit naturally into almost all fixtures and offer great light at 20-25% of the energy cost of incandescent bulbs.1 There is a ton of energy to be saved here, and that makes them the next stop in our series on cutting energy use to make up for falling oil supplies. (see the “Making Up The Difference” category).

This is the first part in this series that does not deal directly in petroleum. However, for the sake of comparison, energy savings will continue to be expressed in barrels of oil. Although oil is rarely used to generate electricity in the United States, it and its derivatives are used in that way worldwide (see post on electricity). Additionally, electricity from other sources can be used to power electric vehicles or heating appliances, filling in for petroleum and other fossil fuels, so the two are increasingly substitutes for each other.

As mentioned above, the energy savings will be roughly 75-80% per bulb that is replaced. This post will be focusing on residential lighting since the very vast majority of that has historically been from incandescent light bulbs. Commercial lighting is more diverse, with considerable power already coming from fluorescent and others being high intensity applications that perhaps are not suited to CFLs, but there are savings to be had there as well. Data from 2001 suggests that a typical United States household uses 940 Kilowatt-hours per year for lighting alone.2 Granted a very small portion of that is already fluorescent lighting, making the figure slightly high for the purpose of measuring bulbs that would be replaced. However, the figure excludes very inefficient halogen torchiere lamps which can also be replaced. These errors operate in opposite directions and should net to a very small amount.

The result then is that United States consumers could save 705-752 kilowatt-hours per household per year by replacing every single light source in their home with a CFL bulb that gives a comparable level of light. This is not the most realistic idea in the world. There are some specialty applications for which there simply is not a CFL available at the moment, such as certain chandeliers. Some consumers may even cling to their old inefficient bulbs just because they find the shape cosmetically appealing, a silly argument considering that a light bulb is not terribly attractive. However, the world will see incandescent bulbs increasingly cast aside. Using the estimate above and a price of 9 cents per kWh, a household can already save about 63.50 on power alone each year on the low-end, so bulb-cost is hardly an issue. In the long run, even incompatibilities and taste issues will disappear.

With 107 million households represented in the survey data, this means that the United States as a whole could consume roughly 7.54*1013 -8.05*1013 fewer watt-hours over the course of year. That is 75.4-80.5 terawatt-hours. Using data on the amount of energy obtainable from a barrel of oil3, then dividing through and dividing by 365.25 days per year, CFLs in US homes could save 121,488-129,587 barrel of oil equivalents per day. Granted, not all of this is actually in the form of oil. Most is likely coal, which also pollutes terribly and is nonrenewable, a sizable amount is from nuclear which is better, and a vanishingly small amount is probably already renewable. As stated above though, even the electricity not generated from oil can serve as a substitute. If electricity demand is kept low, cost will be low relative to oil and people will begin to substitute energy provided from a, hopefully sustainable, power source.

A Word On Mercury

One major concern when talking about CFLs, and other fluorescent lights is that they contain traces of mercury. This is not something to ignore. If you inadvertedly break a CFL bulb, exit the room immediately and let it air out for several minutes. Also worrisome is that there is not currently a well-operating infrastructure to recycle them, at least not here in the states. However, this should not dissuade anyone from immediately switching their frequently-used lighting fixtures to CFLs from conventional incandescent bulbs. As has been shown in a number of sources, the power saved by them would cut mercury emissions resulting from power plants (especially coal). So significant is this impact, that even if every CFL bulb was smashed when it burned out, and its contents released into the air, it would still be a net gain.4 Besides, because of their long life span, and increasing use, recycling programs should arise. It should be noted that when coal plants are replaced, and they inevitably must be someday, the net mercury savings would start to fade, but by then recycling programs should be in place, because that will take decades.

1. Figure is based on the sale in major outlets of 13 watt bulbs meant to replace 60 watt incandescent and 10 watts to replace 40 watt incandescents. Although CFLs cost more to make, they last dramatically longer.
2. Energy Information Administration Data.
3.Data on Energy Yield.
4.Mercury in CFL vs. Power Plant Emissions


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