Alternatives to Mercury-containing Light Sources
This Position Paper contains a brief review of mercury-containing and mercury-free electric lamps
that are in current use and those which may be available in future.
The overwhelming environmental effects from the use of electric lighting are from the power
generation over the life of the lamps. These effects depend on the power source and include
atmospheric emissions of mercury, carbon dioxide, nitrous oxide and sulfur dioxide, noise, and
radioactive waste. Efficient lighting systems which use mercury-containing lamps will typically
reduce these effects by at least 75% because of their lower power requirements. Power
generation effects dwarf any environmental emissions which might occur during the manufacture
or proper disposal of mercury-containing lamps.1
Generally, mercury-free electric lamps cannot be substituted for mercury containing lamps
because of incompatibilities of light output, shape, color, life, electrical characteristics, and
excessive heat, or because their increased energy consumption may violate energy codes, and
overload electrical circuits.
Fluorescent Lamps
Despite continuous research by the private sector, government research laboratories, and
academia, no viable replacement has been discovered for mercury in general purpose fluorescent
lamps. Mercury-free xenon-based fluorescent discharges are available in a flat panel format,
suitable for back lighting of liquid crystal displays. The efficiency is approximately 30% of a
normal mercury-based fluorescent lamp, and therefore this technology is environmentally
counterproductive for general lighting applications.
HID Lamps2
There are better prospects for mercury-free HID lamps. Mercury-free high-pressure sodium
lamps are available up to 150 watts, with some higher wattages under development. This has
been achieved by re-engineering the arc tube geometry and fill pressure. The lamps will retrofit
into existing sockets and operate on existing ballasts.
National Electrical
Manufacturers Association
1300 North 17th Street, Suite 1847
Rosslyn, VA 22209
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Discharge lamps pp 60 et seq. Meyer & Nienhuis – Philips Technical Library
(703) 841-3200
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FAX: (703) 841-5900
High Intensity Discharge (HID) Lamps are used in street lighting, floodlighting,
WEB: http://www.nema.org industrial and some commercial applications
Metal halide lamps without mercury present a greater challenge. These lamps may not be a
“screw-in replacement” for existing types. Maintaining a stable discharge is challenging and the
availability of mercury-free metal halide products is still several years away.
The high-pressure sulfur lamp is fundamentally mercury-free, but is unstable and requires forced
cooling. The lamps which have been marketed so far are high wattage (≥1kW), and they require
coupling to a lighting distribution system such as a light pipe. The overall system efficacy is lower
than an equivalent fluorescent or HID system, especially if the greenish color is corrected by
means of a filter.
Low Pressure Sodium Lamps
This mercury-free light source is characterized by its orange appearance, and very poor color.
Although very efficient in photometric terms, its visual efficiency in typical outdoor (street
lighting) applications is below that of other lamps. All colors are rendered in shades of brown or
gray, making recognition of people and vehicles very difficult. The lamp contains sodium in
sufficient quantities to fail tests for reactivity and ignitability.
Light Emitting Diodes (LED’s)
LED’s are mercury-free, and have a long life. They are very bright and lend themselves to use in
signs, traffic signals, and some accent and display lighting. At the present time, their overall light
output is much less than fluorescent or HID lamps despite their brightness. They are not currently
suitable for most general illumination purposes, but this is a new technology that is evolving very
rapidly.
Incandescent Lamps
Standard Incandescent and Tungsten Halogen Lamps contain no added mercury; however these
lamps are much less efficient than mercury-containing lamps and typically consume approximately
4 times more power for the same light output than a fluorescent lamp. This, in turn, raises the
mercury and other emissions from power generation by a factor of four excluding additional
power needed for air conditioning systems to remove the excess heat.
CONCLUSION
While fossil fueled power generation remains the most significant source of mercury emissions,
efficient lighting will continue to be one of the principal methods of abatement. If emission
controls become commonplace on this source of power, efficient mercury-containing lighting will
still be preferred for its conservation of whatever resources are used for power generation.
Approved by NEMA Lamp Section, April 2001. Members include OSRAM SYLVANIA,
GE Lighting, Philips Lighting, SLI Lighting, ADLT/Venture Lighting, Eye Lighting
International of North America, Ushio America, and Voltarc Technologies.
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