Forcasts for the photovoltaic cell (PV) market in Europe,
the USA and Japan all predict that the amount of electricity
generated by PV is set to rise over the next five years.
This market has attracted certain industrial mineral
suppliers which have sensed an opportunity for growth in this
sector (see panel p.52).
However, solar electricity is one of the most expensive
power sources, and is still largely dependent on supportive
government tax breaks and schemes to make it economically
Ten years ago, Japan was the leading producer and market for
PV, but around five years ago, Europe overtook Japan to become
the leading market.
By 2008, Europe accounted for over 80% of the 5.6GW global
PV market. Spain and Germany are the two leading consuming
countries with markets of 2,511MW and 1,500MW respectively. In
2008, the Spanish market was over ten times the size of the
Japanese market. Last year, the PV market in the USA grew to
342MW, while the Japanese market rose to 230MW.
But not even this growth industry is immune to the current
economic climate. Companies are having trouble raising finance,
and others are making significant staff cuts.
In other cases, institutional investors, some of the main
backers of alternative energy, have withdrawn funding, which
has hit development and production.
| Blocks of polycrystalline silicon awaiting
wiresaw cutting (using SiC) into silicon wafers. Courtesy
PV Crystalox Solar Plc.
Other areas, such as sales of PV cells in the USA for
swimming pool heaters were lower in 2007 and 2008, according to
the Solar Energy Industries Association based in the USA.
Solar energy usage
There are three ways to use energy from the sun; passive
heat, solar thermal heat and photovoltaic energy. Passive heat
is natural sunlight and buildings are now being designed to
minimise heating requirements whilst, solar thermal heat is
used to provide hot water for homes, heating systems or
The third method of using the suns energy are PV
systems, which convert solar radiation into electricity. Within
this, there are PV cells consisting of one or two layers of a
When light shines on the cell it produces an electric field
and causes electricity to flow. The greater intensity of the
light, the greater the flow of electricity. PV cells only
require daylight to operate, not bright sunlight which
increases their applications and geographical range.
PV cells are used in two main ways. The first is PV cell
production for electricity generation, which can be either for
an individual facility or as a concentrating solar power plant
(CSP) or grid to provide power to the existing electricity
networks. The other area is for PV cells to produce solar
energy for thermal applications, such as heating pools, hot
water for homes and heating systems, particularly in the
There are two main types of photovoltaic technology,
crystalline silicon technology and thin film technology. The
most common technology is crystalline silicon, which accounts
for around 90% of the PV cells produced at the moment.
In this, crystalline silicon cells are made from thin slices
of a single crystal (mono-crystalline silicon), or slices from
a block of crystals (polycrystalline or multicrystalline). They
can also be made from grown ribbon sheets.
Commercial solar cells have a conversion efficiency of
sunlight into energy of approximately 15%. In research
conditions, efficiencies have reached 25%.
Thin film PV cells are produced by deposition of very thin
layers of photo-sensitive materials on to a low cost backing
such as glass, stainless steel, or aluminium. Thin film modules
have a much lower manufacturing cost than crystalline
technology, but at the moment this is offset by much lower
efficiency rates of 5-13%. Again, in a research environment,
efficiencies have been as high as 20%.
There are currently four thin film modules commercially
available. These are amorphous silicon (a-Si); cadmium
telluride (CdTe); copper indium/gallium diselenide/disulphide
(CIS, CIGS); and multi-junction cells (a-Si/m-Si). However,
there are other issues with the use of indium and cadmium in
terms of their availability and also environmental concerns
with disposal and usage.
The manufacturing process for silicon cells is very costly,
and a quick run through the production process soon explains
Firstly, high grade quartz is reduced to metallurgical grade
silicon and converted to solar grade silicon using hydrochloric
acid. Solar grade silicon has a purity of 1ppma (or six
nines), compared with the electronic grade silicon for
semi-conductors, which has a purity of seven nines.
The exceptionally corrosive nature of the HCl used to achieve
this purity means that stainless steel equipment has to be
The next step, the Siemans process is also very energy
intensive, passing an electric current through a high purity Si
rod, to produce the reaction to make the high purity
polysilicon at a temperature of ~1,150°C. The silicon is
then melted in high purity quartz crucibles at 1,400°C and
then crystallised out using an Si seed crystal, which is
rotated to produce a cylindrical ingot.
The ingot is cut into a square which results in a 25% loss
of material, and the square ingot then is sliced into wafers.
Slicing is very slow and takes many hours, even with a multiple
wire saw, and losses as saw dust are up to 30%. Slicing is one
of the most costly steps in the Si wafer production
Finally, the wafers are polished and cleaned ready for use
in cell manufacture. In all, silicon wafers probably account
for around 50% of the cost of a PV module. The large volume of
electricity required to produce the silicon wafers is another
limiting factor for wide scale production, until a more cost
effective route can be developed.
However, solar cell research is moving fast and is now
directed at solar specific materials and processes with a focus
on driving energy usage and costs down.
| Comparison of efficiencies of single and
multi-crystalline solar cells
||Approximate market share (2007)
| Sources: PV Crystallox Solar plc; Navigant
Consulting PV programme
There are other PV technologies under development such as
concentrated cells (CSP), which are built into concentrating
collectors that use a lens to focus the sunlight on to the
These use less of the expensive PV cells, while achieving
efficiencies in the order of 20-30%. Another development is
flexible cells which are placed on a thin plastic, which opens
up a new range of applications in buildings and end-user
| PV manufacturing process from quartz to solar
| Source: Meng Tao, Electrochemical Society
Interface, Winter 2008
One of the bottlenecks in the production chain has been
polysilicon supply, as four years ago, there were just seven
producers worldwide. Over the last three years the number of
established polysilicon producers has doubled, with new
production coming on stream in Germany, China and Taiwan.
Additionally, there are a number of other manufacturers
trying to get production facilities up and running in China. If
all these planned facilities come on line, then polysilicon
production is set to grow by over 80% over the next two years
according to the Prometheus Institute for Sustainable
Development in Cambridge, Massachusetts, USA. This is faster
than the demand growth forecast for modules and should ease the
supply situation, further easing module prices. By the end of
2009 or early in 2010, the polysilicon shortage should be
Following the extra capacity coming on stream, polysilicon
prices have dropped from $475/kg to $400/kg on the spot market
over the last few months. However, many polysilicon contracts
are longer term, and so price decreases will not be translated
into the modules for a while. Polysilicon production requires a
high level of investment in facilities, which has limited the
number of players in the market compared with the cell and
module manufacture. For the downstream processes, cell and
module manufacture, there is a lower investment requirement and
also the flexibility to moderate supply to meet changing
Si shortage drives technology
One result of the polysilicon shortage has been the growth
of PV thin film technology, which is now establishing itself as
an alternative. Thin film technologies are based on cadmium
telluride (CdTe), Cl(G)S and amorphous silicon are forecast to
further develop as each will meet the needs of different market
In 2005, thin film technology represented less than 5% of
total PV capacity, representing around 90MW. In 2010, this is
expected to grow to around 20%, accounting for just over 4GW
and to grow to around 25% of the market in 2013 with about 9GW
according to the European Photovoltaics Industry Association
Expanding PV capacity
Solar cell production capacity is expanding rapidly to meet
demand. In Europe, a recent member survey conducted by EPIA
revealed that its members expect production capacity along the
PV value chain to show a compound annual growth rate of 20-30%
over the next five years up to 2013.
In terms of total capacity, Germany has the largest
installed solar electric capacity, with production of 5,308MW,
of which approximately 1,500MW was installed in 2008. The next
major producer is Spain with an installed capacity of 2,973MW,
which saw a huge increase in new capacity in 2008 of 2,281MW,
or about 75%.
Japan is another significant producer of solar energy with
an estimated capacity of 2,173MW, whilst the USA has a capacity
of 342MW. China and Germany are the largest consumers for solar
water heaters, while the USA hosts the majority of the
worlds CSP plants.
The global PV market a vintage year in
Globally, demand for solar panels showed exceptional growth
in 2008, mainly owing to record growth in Spain, which
represented around half of all the new installations in Europe
according to EPIA.
Other established markets including Japan, the USA and
Germany also developed and last year saw the emergence of
significant new markets in South Korea and other European
countries such as Italy and France.
For many years, Germany has traditionally been the largest
market in Europe, but last year Spain accounted for 45% of the
global market and 56% of the 4,503 MW European market. However,
EPIA forecasts that Germany will again overtake Spain, owing to
favourable policies whilst other countries such as the Czech
Republic, Bulgaria, Belgium, Portugal and Greece are putting in
place favourable government policies which should boost
The PV industry is dependent on government support
mechanisms, and the introduction, changing or removal of these
can have significant consequences on the PV industry. For
instance, in Europe, the German and the Spanish government
decreased the incentives for installing solar power.
In Germany, the amount of solar tariff was reduced by 10% to
34.2-48.8 cents per kilo-watt hour. In Spain, a cap was imposed
on feed in tariffs, restricting incentive-eligible solar
installations to 500 MW. This may slow down the explosive
growth seen in the Spanish market in 2008.
Earlier this year, the European Photovoltaic Industry
Association went through an extensive data gathering exercise
and drew up two different market scenarios for the future of
the PV industry.
One is based on moderate growth scenario, and the other is
based on a policy-driven scenario, based on the assumption that
the PV industry is supported by government policies, including
Feed-in-Tariffs (FiT), in a large number of countries.
By 2013, the EPIA forecasts that the global market could
reach 22GW under a policy driven scenario, realising a compound
annual growth rate (CAGR) of 32% over the next five years. The
more moderate growth rates are for an impressive CAGR of 17%
over the same period, with the total market reaching 12GW.
| Development of cumulative global PV
| Source: EPIA
| Historical development of global PV markets by
| Source EPIA
USA CSP leader
In 2008, in the USA, total solar energy capacity grew by
1,265MW to bring the total installed capacity to 9,183MW
according to the Solar Energy Industries Association. This
followed growth in 2007 of 1,159MW, and capacity looks set to
increase again by a similar level in 2009.
To put this into some kind of context, a MW of solar
electric capacity (PV and CSP) is enough to power between 150
and 250 homes, so solar energy usage is still at a fledgling
stage compared with other electricity generating methods, but
has great potential, especially as production costs are bought
down with economies of scale.
The US industry has also been boosted by recent
pro-alternative energy policy decisions. The Emergency
Economic Stabilization Act of 2008 (EESA) enacted last
October, gives the industry a platform to make longer-term
investment and planning decisions.
The act extended the 30% solar investment tax credit for
eight years, and also now allows utilities to make use of the
credit. It additionally lifted the $2,000 cap for residential
PV installations amongst other measures.
The next really positive move for the solar cell industry
was the passing of the American Recovery and Reinvestment Act
2009 (ARRA) in February 2009. This act contains a stimulus
package which will make the solar energy use increasingly
attractive and economically viable for residential and business
in the USA.
The ARRA created a fund to guarantee up to $600,000m. in
loans, specifically for renewable energy and transmission
projects, and also allows for an estimated $5,500m. for
government procurement of energy efficient and renewable energy
The act also established a temporary grant program that will
allow commercial solar customers to receive a cash payment of
30% of the cost of installing solar equipment. All of these
initiatives will mitigate some of the economic pressures on the
solar cell industry during the downturn, and alleviate project
With these positive support measures in place, the PV market
in the USA could grow to 4.5GW by 2013, making it the leading
One of the setbacks the US industry suffered was a
moratorium on applications for solar development on Federal
Lands issued by the Bureau of Land Management, which was
repealed after an outcry. However, the issue of land access is
an important one for the industry as many CSP plants come
closer to commercialisation.
While some of the projects will be going ahead on private
land, much of the land considered for solar development is
managed by the Bureau of Land Management (BLM). The BLM has
instigated a two year Programmatic Environmental Impact
Statement Study for solar installations on its land, which
should be finalised in 2010.
| Solar electric capacity* in 2008
||Total capacity (MW)
||Capacity addition in 2008 (MW)
*Includes PV and CSP, does not including Thermal
capacity (water heating/pool heating/space heating)
Sources: IREC, EPIA, CNE, PV News, SEIA
| EPIA global annual market outlook 2008-2013
Mod EPIA moderate forecast
Pol EPIA policy driven forecast
E - Estimate
Source: European Photovoltaic Industry Association
Prices plummeting in 2009
Early in 2008, there were shortages in the PV supply chain
which drove up prices. This spurred huge investment in silicon
production, cell production and module manufacturing, which has
increased supply worldwide. Then in the third quarter, the
extra production and changes in the European market caused
module prices to plummet
This is bringing about a shake-up in producers but is also
translating into savings for installations as modules typically
account for around 50% of the cost of PV systems. This is
resulting in continued lower prices, making solar units more
affordable and will boost demand in the longer term.
By the end of 2008, module prices were typically $3.50/Wp
(power under peak solar intensity), and installed solar systems
were $7/Wp which translates into electricity that is
around five times more expensive than electricity generated by
Since the beginning of 2009, PV module prices have declined
by 10-20% and are predicted to fall another 10-20% by 2010,
which will aid its affordability.
However, despite all this optimism and forecast growth, it
might be a good idea to put the industry into perspective in
the scheme of power generation. Compared with other forms of
renewable energy such as hydroelectric power and wind, its
usage is relatively minor, largely due to cost.
In 2006, renewable sources accounted for 3.4 Trillion
kilowatthours of electricity or 18% of the global output,
according to the Energy Information Administration in the USA.
Of this, 88% is attributable to hydropower and 3% to wind, and
9% to other sources including geothermal, biomass, biofuels,
tidal and solar power. By 2030, the EIA anticipates that the
renewable share of electricity will be 21%, of which hydropower
will be 70%, wind 18%, and the balance from other sources.
Nevertheless, the PV industry is currently finding cost
competitive applications today, particularly in remote areas
for telecommunications. There is a large potential for repeater
stations for mobile phones powered by PV or hybrid systems.
Hybrid systems are when solar energy is used with another
source of power such as a biomass generator, a wind turbine,
diesel, or grid connected.
Other potential applications include traffic signals and
signs, marine navigation aids, remote lighting, and security
telephones. Off grid applications for rural electricity uses
will also be a growth area, particularly as PV cells become
The biggest drawback to the further expansion of the use of
solar power is its cost. With economies of scale and cost
reduction that will be brought by the increasing development of
photovoltaic electricity, the EPIA estimates that by 2015
photovoltaic electricity will be competitive with electricity
in the south of Europe, and in most of Europe by 2020.
Contributor: Alison Russell is an independent contributor to
IM, she was formerly Deputy Editor, IM, and Editor Mineral
There are relatively few industrial minerals consumed
directly in PV cells, and the volumes to date are relatively
small. Minerals used include quartz as feedstock to produce the
silicon metal wafers and those in glass production such as soda
ash, feldspar, and silica.
Two key minerals used in the PV manufacturing process are
fused silica and silicon carbide (SiC).
Fused silica is the critical ingredient used to manufacture
the crucibles within which silicon metal is melted at
1,400°C, prior to crystallising out.
Cookson Plcs refractories subsidiary, Vesuvius, is a
world leader in manufacturing fused silica crucibles, and has
spent the last few years investing in its fused silica
business, particularly in China.
Indeed, although the company admitted in its 2008 results
that its foundry business had been hit with the global
downturn, its fused silica business grew by 20% compared to
2007, accounting for £72m.($118m.), driven by good
market conditions in the solar cell market.
Fused silica crucibles represent half of Vesuvius
total fused silica revenue, and grew strongly by 44% in 2008.
The demand rise was put down to an acceleration in the solar
energy industry as supply shortages of polycrystalline silicon
used in the majority of solar panels had eased with additional
capacity now coming on stream.
To maintain its position in the industry, Vesuvius completed
two new fused silica crucible facilities in 2008, and a third
is expected to become operational by mid-2009.
In March 2008, a new facility in Moravia, Czech Republic
came on stream and in September 2008 the existing facility in
Weiting, Jiangsu, China had its production capacity
A further new facility close to Weiting, has recently been
completed for a total investment of just over
Following start-up trials, it is expected to become
operational in the second quarter of 2009.
In one of the most costly processes in PV cell manufacture,
silicon carbide is the abrasive component used in wire saw
wafer cutting, and in polishing. Silicon metal ingots require
cutting into manageable sizes, and then the ingot is precision
sliced into silicon wafers.
In 2008, it became clear that traditional SiC markets such
as in refractories and abrasives faced a changing raw material
supply scenario as new higher added value applications such as
in silicon wire sawing for PV began to grow. These applications
demand large quantities of material and were starting to create
a supply deficit, estimated up to 80,000 tpa of SiC (see
SiCs solar eclipse, IM October 08,
However, the economic downturn has temporarily halted the
situation, as demand for other SiC grades in the refractories
and abrasives industries has subsided.
That said, SiC suppliers remain upbeat about PVs
future and its demands on SiC and are taking steps to invest in
research and development, as well as plant capacity to produce
suitable grades. Grain sizes used in wire sawing range
One example is Saint-Gobains SiC department which is
dedicating significant research into improving its production
costs and developing new wire saw grits that the industry will
need for the future.
Saint-Gobain has initiated a PV Roadmap for the
next five to ten years. The company projects that silicon
wafer thickness will be further reduced to improve the cost of
solar cells while increasing their efficiency, and is actively
working on the effect of wiresaw grits on cut-rate, total
thickness variation, warp, bow, subsurface damage, and slurry
systems and their recyclability.