Environmental Engineering Reference
In-Depth Information
Table 2.3 The lab-scale solar cell e
ciencies and commercial-scale solar
panele
cienciesfordifferentPVtechnologiesavailabletodate.Thefigures
given are approximate values for comparison
Highest E
ciency
E
ciency Range
Research
Period Devoted
Reported forLab-
forLarge-Area
PV SolarTechnology
(in years)
Scale Devices (in %) SolarPanels (in %
)
∼
∼
1 (a) Monocrystalline Si
60
25
18-23
∼
(b) MulticrystallineSi
18
12-17
(c) Amorphous Si
∼
14
5-10
2 III-V Compounds
∼
50
∼
40
—
3 CIGS thin-film solar
∼
30
∼
20
10-13
cells
4 CdTe-based thin-film
∼
30
∼
17
10-14
solar cells
5 DSSCs
∼
20
∼
12
5-6
6 Organic solar cells
∼
10
∼
8
—
based on conducting
polymers
instead of the four separate production lines required for Si
technology. This has the potential to make a huge contribution to
cost reduction in the future.
The lab-scale small-device solar cells and large-area commercial
e
ciency values are indicated in Table 2.3. Although CIGS-based
solar cells achieved 20% e
ciency at lab scale, the commercialisa-
tion rate is comparatively slow. The reason has been the di
culty
in materials growth reproducibility due to the involvement of
four elements in this alloy material. All other devices are also
progressingforward,butCdTecommercialisationisveryimpressive.
A US company, First Solar, has produced
∼
1m
2
solar panel with
∼
10-14% e
ciency and is rapidly ramping up its manufacturing
capacity. After establishing the first production line in the US, First
Solar now has plants in Germany and Malaysia and is spreading
out to many other countries. The production volume is impressive,
exceeding 1 GW per annum in 2009.
In the past, the use of Cd in PV solar cells was considered
a hazard. However, this perception has now completely reversed.
The world produces about 22,000 tonnes of Cd annually as a by-
product of Zn and Cu processing [11]. A proportion of this is
