If all of the world's
light bulbs were replaced with energy-efficient LEDs for a period of 10 years,
researchers at the US Rensselaer Polytechnic
Institute claim, oil consumption would be cut by 962
million barrels, removing the need for 280 power stations, cutting carbon
dioxide emissions by 10 billion tonnes, and ultimately result in financial
savings of $1.83 trillion.
Rensselaer, known for fundamental LED research, has been looking at environmental
the transistor meant to the development of electronics, the LED means to the
field of photonics. This core device has the potential to revolutionise how we
use light," said Professor Fred Schubert in a paper: "Transcending the replacement paradigm of solid-state
lighting," published in Optics Express late last year.
paper, co-written with researcher Jong Kyu Kim, is excellent, contains
predictions on what LED technology is likely to exist, and is available for
free at the OpticsInfoBase website. .
Each year, an estimated 600 million fluorescent lamps are
disposed of in U.S. landfills amounting to 30,000 pounds of mercury
In 1992, mercury-containing lamps were added to
the United States' Environmental Protection Agency's (EPA) list of
hazardous substances. (The EPA's regulatory threshold of 2 mg./litre is
usually exceeded by mercury-containing lamps).
The Mercury from one fluorescent bulb can pollute 6,000 gallons of water beyond safe levels for drinking
Almost all modern high output light sources depend on using mercury
inside the lamps for operation. When considering the environmental
impact of the mercury in lighting, we must take three factors into
- The type of mercury (solid or liquid) which is present in the lamps,
- The amount of mercury present in a particular type of lamp, and
- The lifespan of the lamp which will determine the amount of mercury used per hour of operation.
Liquid mercury, which is the most common form of mercury used in
lighting, represents the greatest hazard. If a lamp is broken, the
liquid mercury can find its way into cracks in concrete flooring, the
fibers of carpets, or into spaces in other floor coverings. Over time,
the mercury will evaporate into he atmosphere causing a local “hot
spot” of low level contamination. The more liquid mercury present in a
lamp, the longer the resulting contamination will last.
the total amount of mercury contained in a typical fluorescent
tube (approximately 20 milligrams), were to mix completely and
evenly in a body of water, it would be enough to contaminate
around 20,000 litres of water beyond Health Canada limits for
safe drinking water (0.001 milligrams of mercury per litre of
water)” - Environment Canada 
Mercury can be compounded with other metals, into a solid form called
an amalgam - this is the type of mercury used in induction lamps. It is
similar to the once widely used dental amalgam in tooth fillings. The
solid form of mercury poses much less of an environmental problem than
liquid mercury. The amalgam form of mercury is also less of a heath
hazard as it is not as readily absorbed into the skin (than the liquid
form) should one come into contact with the amalgam - it has low
"bio-availability". The small slug or pellet of amalgam can easily be
recovered (always wear disposable gloves) in the case of induction lamp
breakage and therefore can be disposed of properly with little or no
risk of creating a locally contaminated area. The solid mercury amalgam
is also simpler to recover for recycling at end of lamp life.
Induction lamps use the least amount of mercury of any lamp
technology, when considered based on both initial quantity and amount
used per 20,000 hours of lamp life. Induction lamps are therefore much
more environmentally friendly since they use very little mercury over
their lifespan. Further, the mercury is in solid amalgam form reducing
contamination in the case of accidental breakage and making recovery for
The chart below puts this
information into visual form for the most common types of industrial,
commercial and retail lighting technologies.