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Comparison of Life-Cycle Analyses of Compact Fluorescent and
Comparison of Life-Cycle Analyses of Compact Fluorescent and
Incandescent Lamps Based on Rated Life of Compact Fluorescent Lamp
Laurie Ramroth
Rocky Mountain Institute
February 2008
Image: Compact Fluorescent Lamp. From Mark Stozier on istockphoto. Abstract
This paper addresses the debate over compact fluorescent lamps (CFLs) and incandescents through
life-cycle analyses (LCA) conducted in the SimaPro
1
life-cycle analysis program. It compares the
environmental impacts of providing a given amount of light (approximately 1,600 lumens) from
incandescents and CFLs for 10,000 hours. Special attention has been paid to recently raised
concerns regarding CFLsspecifically that their complex manufacturing process uses so much
energy that it outweighs the benefits of using CFLs, that turning CFLs on and off frequently
eliminates their energy-efficiency benefits, and that they contain a large amount of mercury. The
research shows that the efficiency benefits compensate for the added complexity in manufacturing,
that while rapid on-off cycling of the lamp does reduce the environmental (and payback) benefits of
CFLs they remain a net win, and that the mercury emitted over a CFLs lifeby power plants to
power the CFL and by leakage on disposalis still less than the mercury that can be attributed to
powering the incandescent.

RMI: Life Cycle of CFL and Incandescent 2 Heading
Page
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Introduction
5
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Background
5
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The CFL Versus Incandescent Debate
5
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Benefits and Detriments of CFLs and Incandescents
5
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Life-Cycle Analysis
6
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Lamp Data Collection
7
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Assumptions
9
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Assembly
10
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Operation
10
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Disposal
10
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Data Analysis
10
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Qualitative Discussion of Carbon Dioxide Emissions: Greenhouse-Gas Pollutants
11
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Qualitative Discussion of Other Non-Carbon Dioxide Pollutants
12
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Mercury Discussion
12
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Lead and Other Toxins Discussion
13
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Sensitivity Analysis
14
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Electronic Ballast Factor
14
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Operating Cycle (On/Off Cycle of Lamp)
14
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Disposal Options and Recycling
17
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Conclusion
18
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Appendix A
19
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Operation of a CFL
19
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Operation of an Incandescent Lamp
20
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Establishing Light Equivalency
20
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Life-Cycle Path Assumptions
21

RMI: Life Cycle of CFL and Incandescent 3 ........................................................................................
Modeling of CFL Ballast in SimaPro
21
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Calculations
21
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Coal Savings
21
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Predicted Mercury Emissions
22
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Validation By Comparison With Wal-Mart Claims
22
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Appendix B
24
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Bibliography
24

RMI: Life Cycle of CFL and Incandescent 4 Introduction
This document provides an evaluation of the environmental impact of lighting a room for 10,000
hours with CFLs, and, alternatively, with incandescents over the products entire life. Several claims
have been made recently challenging the green credentials of CFLsspecifically that their
complex manufacturing process uses so much energy that it outweighs the benefits, that turning
CFLs on and off frequently eliminates their energy-efficiency benefits, and that they contain a large
amount of mercury.
The processes modeled using SimaPro for the two scenarios are thought to represent industry
averages. However, the life cycle of each bulb is unique, and this paper cannot include absolute
judgements on all CFLs and incandescents. The authors goal is to educate the reader on the
differences between these two lighting options life cycles, and to explore the claims described above.
Background
The CFL Versus Incandescent Debate
CFLs were invented by a GE engineer in response to the 1973 oil crisis.
2
They have been on the
market since the early 1980s, but they have only recently been touted as a key component in the fight
against global warming. The unmistakable CFL image has become an icon of energy awareness and
environmental concern as it represents an easily implemented and financially smart tool to reduce
greenhouse-gas emissions. The rise of CFLs importance as the avant-garde of a climate change-
conscious society was cemented in December 2007 when the President signed a law requiring the
gradual phasing out of incandescents.
3,4
The benefits of CFLs have prompted the phasing out of
incandescents in several countries. Australia has led the way with a plan to phase out incandescents
by 2010. Great Britain and Canada have similar plans in place. In America, the President recently
passed the Energy Independence and Security Act of 2007; this includes a measure for phasing out
incandescents.
5,6
The bill includes efficiency requirements for manufacturers as well as the phasing
out of 100 W to 40 W bulbs as part of an ongoing program that begins in 2012 and ends in 2014.
Performance requirements for manufacturers of incandescents include a 2530 percent reduction in
energy use compared to todays most common incandescent bulbs by 2014 and a 70 percent
reduction by 2020.
Despite their rising popularity, concerns have been raised that CFLs might actually be worse for the
environment due to their mercury content, the impact of short on times on the life of the lamps,
and the energy used during their complex manufacturing process.
In order to address these three concerns, this study compares the greenhouse-gas emissions and
toxic releases that can be attributed to lighting a room for 10,000 hours with 1,600 lumens of light
from a CFL and the toxic releases that can be attributed to lighting a room for 10,000 hours with
1,600 lumens of light from an incandescent. To calculate these emissions, we did life-cycle analyses
(explained below) using the software tool SimaPro.
Benefits and Detriments of CFLs and Incandescents
CFLs and incandescents produce light through fluorescence and incandescence, respectivelytwo
processes that are further explained in the
Operation of a CFL
and
Operation o