| solar deployment advances
Photovoltaics: State of the Technology, 2012
The following module manufacturers led global markets in 2010:
1. Suntech Power (China) 1.57 GW (Si)
2. JA Solar (China) 1.46 G W (Si)
3. First Solar (USA) 1.41 GW (Cd Te)
4. Q-Cells (Germany) 1.01GW (Si)
5. Motech (Taiwan) 0.85 GW (Si)
6. Gintech (Taiwan) 0.72 GW (Si)
7. Sharp (Japan) (Si, a-Si, mc-Si)
8. Kyocera (Japan) (Si)
The ranking is volatile. Sharp was the global leader
for years. Q-Cells assumed the lead, until it experienced a
financial crisis in 2008. First Solar took the helm the following year.
For 2010, Paula Mints of Navigant Consulting divides
market share by technology this way:
•;Monocrystalline;silicon;–;roughly;43;percent
•;Multicrystalline;silicon;–;roughly;43;percent
•;Cd Te;–;9;percent
•;CIS/CIGS;–;2;percent
•;Amorphous;silicon/multicrystalline;silicon;–;2;percent
Copper;indium;selenide;(CIS);appears;to;be;the;up-and-coming;seg-
ment. The latest example was the announcement in April that Solar Frontier,
a;company;of;the;Shell;Oil;Group;in;Japan,;opened;a;new;factory;for;CIS
modules;in;Japan.;In;July;they;reached;their;target;manufacturing;capacity
of;1;gigawatt;(GW),;including;900;megawatts;at;the;new;plant.
Gallium arsenide (GaAs) cells have the highest efficiencies, achieving
up to 43 percent recently. High cost limits their market to space satellites
and concentrating photovoltaic (PV) systems.
While there’ve been only incremental improvements in crystalline silicon conversion efficiency for 40 years, they still offer better specific performance than thin-film cells, at 18 percent and higher for modules now widely
available. SunPower leads with up to 25 percent efficiency for cells. The
performance advantage is somewhat offset by the higher complexity of the
silicon technology and hence a somewhat higher production cost.
The typical thin-film cell has roughly 1 percent the thickness of a comparable silicon cell, implying economies of material and production. Today’s
market leader in thin film is cadmium telluride (Cd Te), with conversion
efficiencies as high as 12 percent. A thin additional intermediate layer of
cadmium sulfide (CdS) contributes to this efficiency. The simpler thin-film
technology leads to attractive manufacturing costs: First Solar has achieved
half-a-euro per watt. But cadmium is a poisonous heavy metal. This raises a
problem in Japan, which has a history of cadmium pollution.
No;wonder;then;that;Japan;has;turned;its;attention;to;CIS;and;amor-phous silicon. The Japanese firm Solar Frontier mentioned has claimed a
record;CIS;efficiency;over;15;percent.;The;National;Renewable;Energy
Laboratory;(NREL);recently;measured;15. 5;percent;on;a;30-by- 30;cen-
timeter;(12-by- 12;inch);CIS;cell;from;Avancis.;The;problem;is;a;looming
scarcity of indium, which may limit mass production.
Finally, amorphous silicon and multicrystalline silicon show promise. A new
record,;12;percent,;has;been;reported;by;NREL,;on;a;cell;measuring;400;square
centimeters. This marks tremendous progress since the days of stability problems
linked to the Stabler-Wronski effect in hydrogenated amor-
phous silicon. The solution, developed in Switzerland, was a
combination with multicrystalline silicon layers.
By WOLFGANG
PALZ, PH.D.
For 20 years, Wolfgang
Palz, Ph.D., managed
renewable energy
development for the
European Union Commission in Brussels.
