Environmental Engineering Reference
In-Depth Information
final product, it is easy to recognise the three different types of
solar panels produced using crystalline Si, polycrystalline Si, and
amorphous Si.
2.3 PV-Manufacturing Cost Based on Si Technology
The cost of PV technology is given in $/W, as shown in the following
relationship:
Cost of solar power
$
W
Production Cost
⇓
Cell E
ciency
⇑
Both the reduction of production cost and the improvement of cell
e
ciency are challenging for Si technology, even after 60 years
of research and development efforts. Si, however, dominates the
PV industry because of the matured knowledge and established
technology developed in this 60-year period. About 85% of the
solar panels sold worldwide today are made of Si. The domination
of Si will continue for some time, until real breakthroughs take
place within alternative technologies and low-cost solar panels
are manufactured on a large scale. Even with the high cost of PV
technology, the size of the PV market is currently in excess of $40
billion per annum and the market growth rate is over 45%. Some
reports quote figures as high as
∼
68% for the growth rate of PV
technology for the year 2004 [3].
In the early 1970s, the cost of PV solar energy production was
over US$20/W. This has been reducing continuously to a present
valueof
∼
US$2-3/W.ThePV-manufacturingcostreductionbetween
1980 and 2010 is given in Fig. 2.6, showing an impressive progress
inthePVfield.Thisreductionhasbeencarriedoutbyusingallthree
Si technologies summarised above.
Asthecrystallinityreduces,thee
ciencyofcellsreducesandthe
stability and lifetime suffers. Also, since the Si material is expensive,
work is continuing to reduce the thickness of Si wafers from
∼
0.3
mm(300
μ
m)to
∼
0.15mm(150
μ
m),butthishasotherdetrimental
consequences, such as the breaking of wafers in the production
process.ThesearethemainissueswithSitechnology,and,therefore,
cost reduction is now progressing extremely slowly. However,
numerous approaches to reduce material usage and increase the
=
