Metals Shortages and Their
Impacts on the Long Term
Feasibility of LED Supply
Version 1
1 Introduction
Most lighting policy measures have been concerned with encouraging the uptake of
energy efficient lamps. Future improvements in the luminous efficacy1 of electric
lamps are based around the widespread availability and use of light-emitting diodes
(LEDs). However, raw material availability is a potential concern. LEDs contain rare
elements such as gallium and indium. Any future shortages of these elements might
limit the number of LEDs that can be produced, or at least increase their cost and
reduce uptake. This is an important issue because MTP models and strategies are
based on the premise that LED usage will grow substantially.
This Briefing Note reviews current LED composition and identifies long term trends in
prices and availability of LED materials, such as gallium and indium. Using data from
the MTP models, future demand for LEDs and these materials is identified. This
Report outlines the future feasibility of long term large scale LED production, and
presents the results of long term modelling to assess the impact on LED market of
raw material shortages. The feasibility of recycling gallium and indium from LEDs is
also discussed.
2 LED composition
LEDs are diodes which emit light in a range of colours when an electric current is
passed through them in one direction. This phenomenon is called
electroluminescence.
Early LEDs were made from gallium arsenide and emitted invisible infrared radiation.
The first commercial red LEDs made from gallium arsenide phosphide appeared in
the late 1960s, green LEDs made from gallium phosphide appeared in the 1970s,
but blue LEDs made from gallium nitride appeared only in the 1990s owing to the
technological hurdles that first had to be overcome.
Currently LEDs are made from a variety of semiconductor materials that combine the
elements gallium, aluminium and indium with arsenic, phosphorus and nitrogen.
Table 1 below shows some examples of semiconductor materials used in the
1
The luminous efficacy of a lamp is the ratio of the quantity of light emitted by the lamp divided by the
power consumed by the lamp and ballast.
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manufacture of LEDs. Silicon carbide and sapphire can be used as substrates2 for
blue LEDs to improve their efficiency.
Table 1 Examples of semiconductor materials used in the manufacture of LEDs
Semiconductor material
Aluminium gallium arsenide
Aluminium indium gallium phosphide
Gallium arsenide phosphide
Indium gallium nitride
Gallium nitride
Abbreviation
AlGaAs
AlInGaP
GaAsP
InGaN
GaN
LED light colour
Red
Red, Orange, Yellow
Red, Orange, Yellow
Green, Blue
Green, Blue
White light LEDs can be made by combining red, green and blue LED chips3 or by
coating a blue or green LED chip with a phosphor to convert UV rays emitted by the
chip into visible light.
Cerium-doped4 yttrium aluminium garnet is often used as the phosphor coating for
white LEDs, but terbium and gadolinium can also be used as a substitute for cerium.
White LEDs can also be made by coating near ultraviolet emitting LEDs with a
mixture of high efficiency europium based red and blue emitting phosphors plus
green emitting copper and aluminium-doped zinc sulphide.
Other components enclosed in the LED device 5 contain additional metals such as
gold, silver, iron, copper, nickel and lead. Gold has low electrical and thermal
resistivity and assists the thermal management of LEDs, while silver is valuable as a
reflective coating and metallic finishing.
Therefore, gold is used in the conductive metallic wires to connect the electrodes to
the LED chip and in the finishing on the heat sink, stud bumps and solder layer,
while a silver coating is used to increase efficiency of light reflection from LEDs or as
the coating and finishing on the heat sink, or in adhesives and glue.
As part of a recent study (Seong et al, 2011) on potential environmental impacts of
LEDs, the average metallic content of LEDs of various colours and low (50 to
400mcd6) and high (900 to 10,000 mcd) luminous intensities was determined and the
results can be found in Figure 1. The average weight of an LED chip analysed in this
study was 300mg.
2
A substrate is a thin slice of material serving as the foundation upon which the LED chip is
deposited.
3
An LED chip is the slice of semiconducting material doped with impurities to create the p-n junction
where energy in the form of photons is emitted by electrons falling into lower energy levels after
meeting holes.
4
Cerium-doping is the introduction of cerium impurities into the pure semiconductor in order to
modulate its electrical properties.
5
An LED device is the entire light-emitting diode which converts electrical energy into light.
6
1 mcd (millicandela) is 1/1000 of 1 candela, the SI measuring unit of the luminous intensity
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Figure 1 Average metallic content (mg) of the analysed LEDs
Average metallic content (mg)
1000
98.355
100
10
0.7819
0.6304
1
0.2796
0.1218
0.1
0.0351
0.0153 0.021
0.0079
0.01
0.001
0.0209
0.0003
Silver
Nickel
Phosphorus
Metals present in LEDs
Lead
Iron
Indium
Gold
Gallium
Copper
Arsenic
Aluminium
0.0001
The results confirmed that the LEDs analysed contained high levels of iron, nickel
and copper. The lead content of the low-intensity red LED was also high. However,
because elements like iron, copper, nickel and lead are commonly used in many
types of industry and products, and they are widely available, this Briefing Note
refers mainly to specific elements used in the manufacture of LEDs, such as gold,
silver, gallium and indium.
Little research has been undertaken so far in order to determine the metallic contents
of LEDs, and information provided by LED manufacturers does not include the
quantities of different metals in their products. For this reason, the values determined
by the study mentioned above (Seong et al, 2011) were used as reference values for
the following analysis.
This study does not include any data relevant to the content of phosphors of white
LEDs, and given the lack of relevant information the amount of yttrium was estimated
from data about Philips Lumileds LumiramicTM phosphor technology (Schnick, 2009).
3 Costs and availability of LED metals
Due to the growth of semiconductor production following a rapidly increasing market
for electronic devices and a growing range of applications, availability of materials
and associated price increases have become a source of concern in the last decade.
Approximately 95% of the world’s supply of gallium is used for the production of
compound semiconductors (Davis, 2001), while indium is being consumed in
unprecedented quantities for making flat-panel displays. Both gallium and indium are
also used to manufacture solar cells and high-efficiency LED lighting products.
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Raw material availability is a potential concern. Most LEDs are based around gallium
and indium compounds, and both gallium and indium are rare elements. This is likely
to limit the number of LEDs that can be produced. A study by Kleijn at the University
of Leiden has highlighted the shortage of gallium and indium, and concludes that it is
likely not to contribute to more than 1% of solar cells for this reason (Cohen, 2007).
LEDs use less gallium and indium than solar cells, but it is likely that in the medium
term alternative materials will have to be identified. Another study by Reller at the
University of Augsburg has also concluded that world supplies of indium could run
out by 2017 (Cohen, 2007).
The European Commission has published a list of 14 critical raw materials at EU
level, which display a particularly high risk of supply shortage in the next 10 years
(EC, 2011). Gallium and indium are on this list, as they are essential in the
production of various electronic devices, and the EU is completely dependent on
imports, with China accounting for 97% of world production in 2009. No recycling or
substitution processes for gallium and indium are currently commercially viable. Gold
and silver are not currently listed as critical materials.
Another article also draws attention on metal shortages and the role of recycling
(Rhodes, 2008). It includes gold, indium and silver amongst metals under threat and
estimates the world total reserve and the expected time of exhaustion based on
current rates of production and their principal uses, as shown in Table 2 below.
Furthermore, it is predicted that the growth in world population, along with the
emergence of new technologies will result in some key metals being used up rapidly:
indium in 5 to 10 years, and silver in 15 to 20 years (Rhodes, 2008).
Table 2 Estimates of world reserve and depletion time for critical metals
Metal
World reserve
Estimated depletion time
Gold
89,700 tonnes
45 years
Silver
569,000 tonnes
29 years
Indium
6,000 tonnes
13 years
The main sources for gallium are from the aluminium ore bauxite, and from zinc ores.
The US Geological Survey estimates the gallium content of world deposits to be
more than a billion kilograms (USGS, 2002-2011). These estimates assume a
gallium concentration of 50 parts per million. The main source for indium is a zinc
sulphide ore, where indium concentration varies from 1 part per million to 100 parts
per million. Because gallium and indium can only be accessed if the deposits are
economic, it is estimated that only a small proportion of the gallium and indium in
these ores is economically recoverable. However, in his study Reller also estimates
that zinc could be used up by 2037 (Cohen, 2007), while Cohen (2007) states that
zinc could be exhausted in 20-30 years if predicted new technologies appear and the
population grows.
Based on the data provided by the US Geological Survey for world resources and
production of the metals and rare earths discussed above, estimates of the depletion
periods for these elements have been derived. Although the available data may not
entirely reflect the current global situation, it is clear that some elements present an
increased potential of depletion in the coming decades. The most critical elements
appear to be indium and yttrium, which could be depleted by 2018 and 2022,
respectively.
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Due to high demand for the materials that are used for LED production, pressure has
been put on raw material prices and the imminent depletion of raw material could
already be seen in these prices. The high costs of these materials are mainly caused
by the rarity of the source metals, but metal prices have varied significantly in the
past years. The price of several metals like gallium and indium fell dramatically
following the 2008 economic crash, but improving economic conditions subsequently
increased prices. The price of other metals like gold and silver has increased
gradually in the past years.
shows the price of gold, silver, gallium, indium and yttrium in past years
(USGS, 2002-2011), along with the price evolution of the average LED metal
contents.
Table 3
Table 3 Prices of raw metals and of average LED metal contents
Year
Gold
Raw metal
($/ounce)
LED content
(¢/LED)
Silver
Raw metal
($/ounce)
LED content
(¢/LED)
Gallium
Raw metal
($/kg)
LED content
(¢/LED)
Indium
Raw metal
($/kg)
LED content
(¢/LED)
2002
2003
2004
2005
2006
2007
2008
2009
2010
311
365
411
440
606
699
874
975
1200
0.0230
0.0270
0.0304
0.0326
0.0449
0.0518
0.0647
0.0722
0.0889
4.62
4.91
6.69
7.15
11.61
13.43
15.02
14.69
17.75
0.0020
0.0021
0.0029
0.0031
0.0050
0.0058
0.0065
0.0063
0.0076
530
411
494
512
443
530
579
449
670
0.0008
0.0006
0.0008
0.0008
0.0007
0.0008
0.0009
0.0007
0.0010
97
170
643
810
918
795
685
500
565
2.9E-06
5.1E-06
1.9E-05
2.4E-05
2.8E-05
2.4E-05
2.1E-05
1.5E-05
1.7E05
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As can be seen from Table 3 above, the price of each metal contained in one LED
chip is very low and although it is estimated that it will grow gradually, it will continue
to have a low value. Following the same average price increase, analysis shows that
by the year 2030 it is expected that one LED chip will contain gold in value of 1.7p0,
silver in value of 0.15p, gallium in value of 0.02p, indium in value of 0.01p and yttrium
in value of 0.01p.
Based on this estimation, it seems that metal price increases of the sort already
encountered will not affect the price of LEDs too much. However, faster depletion of
such metals might lead to an accentuated price increase for raw metals. On the other
hand, LED prices are expected to decrease in coming years due to their increasing
quantities on the lighting market. Price increases for raw metals might slow down the
rate of decrease in prices for LEDs.
Paradoxically, it is typical for the price and costs of extraction of raw metals to
decline initially as the metal is produced and reserves are depleted. Technological
innovation can lead to lower exploration costs, which in turn can cause the price to
fall over time, until eventually scarcity of the resource causes the price to rise. The
true scarcity is only revealed towards the end of exhaustion, when an intense price
rise occurs with a huge cut in production. The true size of the resource base is
unpredictable, and therefore it is possible for a very high magnitude price increase to
occur over one or two years after a hundred years of declining prices and increasing
production (Reynolds, 1999).
4 Feasibility of recycling of metals from LEDs
While recycling of base metals such as gold and silver from scrap is a mature part of
the metal industry, current efforts to recover and recycle rare metals are far less well
advanced. For metals such as gallium and indium, recycling is the only way to
extend the lifetime of critical sectors of the electronics industry, including LEDs.
While gallium from old scrap is not currently recycled, substantial quantities of new
scrap generated in the manufacture of devices based on gallium arsenide are
reprocessed. Indium is currently most commonly recovered from the indium tin oxide
recycling process (USGS, 2002-2011), which is concentrated in countries where
indium tin oxide production and sputtering take place, such as China, Japan and the
Republic of Korea. Nevertheless, the European Commission has cited a recycling
rate of 0% for gallium and 0.3% for indium (EC, 2011).
Higher recycling rates would reduce the pressure on demand for primary raw metals,
help to reuse metals which would otherwise be wasted, and reduce energy
consumption and greenhouse gas emissions from extraction and processing.
Although they are globally recycled on a large scale, there is no detailed information
about recycling gold and silver used in the manufacture of LEDs. Current technology
allows recycling of gold used for conductive wires, stud bumps, solder layer and
finishing on the heat sink. Silver used as the coating and finishing on the heat sink
can also be recycled. There is not sufficient information about recycling of gallium
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and indium used in different semiconductor materials to create the light-emitting
diode. Manufacturers of LEDs say that they use virgin raw materials for this process.
The WEEE European Commission Directive encourages materials recycling and
requires electrical and electronic equipment to be taken to a suitable authorised
treatment facility at the end of its life so that it can be treated / dismantled and
materials recovered for recycling where possible (EC, 2003). LEDs are within the
scope of this Directive, which proposes targets equal to 65% of the average weight
of the electrical and electronic equipment.
5 Feasibility of long term large scale LED production
Based on data taken from the MTP models, it can be estimated that the number of
LEDs sold in the UK will continuously grow in the coming years. For instance, the
number of LED lamps sold on the UK market may be 40 times higher than the
current LED sales level.
Considering the same evolution of LED worldwide sales, and based on the
assumption that the number of LED lamps sold in a country depends on the size of
the economy of that country in relation to the world global economy measured by
Gross National Income, it can be estimated that the average number of new LED
lamps sold worldwide may exceed 250 million units by the year 2030 (based on
expert assumption).
The world production of different metals in coming years can be estimated based on
recent production data. With the reference value for the average metal content in
section 2 above, the relative metal demand for LEDs can be determined in the long
term.
Table 4 below summarises the results of the research, carried out for this report, on
the feasibility of LED production by the use of different elements, for the year 2010.
Table 4 Overall results of the research study
World
Relative LED
production
raw material
in 2010
demand
(tonnes)
(%)
Gold (price unit: ounce)
0.021
2,500
0.000185
Silver (price unit: ounce)
0.1218
22,200
0.0001
Gallium (price unit: kg)
0.0153
106
0.003
Indium (price unit: kg)
0.0003
574
0.00001
Yttrium (price unit: kg)
2.269
8,900
0.00562
LED
content
(mg)
World
reserve in
2010
(tonnes)
Recycling
level in
2010
(tonnes)
Estimated
depletion
year
Current
price
(£/unit)
Current
price per
LED chip
(p/LED)
51,000
707
(a)
778
0.0576
510,000
5,520
(a)
11.51
0.0049
(b)
0
(b)
434
0.0007
6,000
5
2017
366
0.00001
540,000
0
2021
56
0.0127
Notes to Table 4:
(a) Depletion years for gold and silver are difficult to estimate because of the high level of recycling
and the possibility that this could increase further.
(b) World reserves of gallium are difficult to estimate because gallium is extracted from small
quantities in other ores, and the amounts available depend on the proportion of gallium in these ores
that can be economically extracted.
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Despite the significant future increase in LED sales, the relative demand for metals
required for the manufacture of LEDs is very low compared to world total demand of
the same metal. This is shown in the third column of Table 4, which gives the
percentage of world production that is used to make LEDs. It can be predicted that
by 2030 LEDs would require 0.006% of the world production of gold, 0.0009% of the
world production of silver, and 0.011% of the world production of gallium.
Moreover, there has been a continuous increase in LED luminous efficacy over
recent years and it is predicted that it will improve further in the future. Together with
the progress in LED technology allowing LEDs to be used in applications other than
just directional lighting, this scenario may lead to a greater increase in LED global
demand. Nevertheless, this does not seem to affect excessively the relative metal
demand mentioned above, and it may be concluded that long term large scale LED
production would not have impacts on metal resources in the next few decades.
However, the reverse phenomenon might occur with a decrease in world metal
reserves due to other sources of demand. As estimates predict that several metals
used in the manufacture of LEDs may reach depletion in 6 to 45 years, strong
impacts might be expected on the LED market. Recycling would help prolong LED
metal reserves, but long life time expectations up to 50,000 hours (approximately
11.5 years for an average operating time of 12 hours daily) may not allow recycling
to meet its aim for some rare metals, such as indium which is expected to reach
exhaustion in 6 years.
Whereas gold and silver could be replaced with other materials of equivalent
physical properties, the challenge is to find materials suitable to replace those
elements with high risk of depletion in the coming decades, such as indium and
yttrium.
6 Conclusions
The metal market generally follows a cyclical pattern based on supply and demand.
Strong economic growth leads to a major rise in demand for raw materials which
may reflect in high price levels. Whereas, innovation in extraction technologies may
decrease metal prices until scarcity becomes probable.
According to various studies, specific metals used in the manufacture of LEDs, such
as rare metals like gallium and indium, but also base metals like gold and silver, are
expected to reach exhaustion in periods of time of as little as 6 years (which is the
case for indium).
Gallium and indium, which are essential metals in the manufacture of LEDs, are
listed among the 14 critical raw materials, with a particularly high risk of supply
shortage in the next 10 years, and no recycling or substitution processes are
currently commercially viable for these metals. Yttrium is another element used in
phosphor coatings of LEDs which has a significant risk of depletion in the next 10
years.
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Gold and silver are not currently listed as critical materials, and they are widely
recycled in the metal industry.
Long term modelling, to assess the relation between LED market future evolution
and raw metal shortage potential, has shown that future increase of LED sales levels
will not significantly affect the metal reserves. This is because LEDs only contain
very small amounts of the rare elements. However, it is possible that metals
shortages, especially of indium, might have strong impacts on LED large scale
production. In order to counteract this risk, alternative materials are needed.
7 References
Cohen, D. (2007) ‘Earth’s natural wealth: an audit’, New Scientist, 2605:34-41
Davis, S. (2001) ‘Capacity Issues in the Material Supply Chain’. On-line Digest, The
International Conference on Compound Semiconductor Manufacturing Technology.
Available at: www.csmantech.org/Digests/2001/PDF/1_3_Davis_V3.pdf
EC (2003) ‘Directive 2002/96/EC of the European Parliament and of the Council of
27 January 2003 on waste electrical and electronic equipment (WEEE)’, Official
Journal
L
037,
13/02/2003,
p.
24–39.
Available
at:
http://eurlex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32002L0096:EN:HTML
EC (2011) ‘European Commission Communication 25 Tackling the challenges in
commodity markets and on raw materials’. Available at:
http://ec.europa.eu/enterprise/policies/rawmaterials/files/docs/communication_en.pdf
Reynolds, D. B. (1999) ‘The mineral economy: how prices and costs can falsely
signal decreasing scarcity’. Ecological Economics, 31(1999):155-166
Rhodes, C. (2008) ‘Metals shortages’. Available at: http://scitizen.com/futureenergies/metals-shortages-_a-14-2223.html
Schnick, W. (2009) ‘Shine a light with nitrides’, physica status solidi (RRL) – Rapid
Research Letters, 3 (7-8): A113–A114
Seong-Rim, L., Kang, D., Ogunseitan, O.A. & Schoenung, J.M. (2011) ‘Potential
Environmental Impacts of Light-Emitting Diodes (LEDs): Metallic Resources, Toxicity
and Hazardous Waste Classification’, Environmental Science & Technology, 45:320327
Steen, B. (1999) ‘A systematic approach to environmental priority strategies in
product development (EPS)’, Chalmers University of Technology. Available at:
http://www.cpm.chalmers.se/document/reports/99/1999_4.pdf
USGS (2002-2011) US Geological Survey. Available at: http://www.usgs.gov
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