Civil Engineering Reference
In-Depth Information
Table 12.4
Photovoltaic fi rst generation summary
Monocrystalline silicon (single crystalline)
Effi ciency
14-16%
Degradation
0.25-0.50% every year
Advantages
Due to the production process has a large possible
output power
Currently most commonly used technology
Most commercially viable technology
Disadvantage
Cost is an issue due to their production technique
Polycrystalline silicon (semi- or multi-crystalline)
Effi ciency
10-11%
Degradation
0.25-0.50% every year
Advantages
Unlike monocrystalline, can be easily shaped
Effi ciency losses are not good but are being improved
through R&D
Disadvantage
Uses a lower grade of silicon which is also lower in
cost but less effi cient
share, but this is changing (Brown and Wu, 2009). One of the issues with
this technology is its manufacturing process, which is expensive and based
on the same principles as the computer industry, with the two major ele-
ments being the requirement for pure silicon (with the higher purity pro-
viding greater possible effi ciency), and the single-junction photon energy
extraction. Crystalline silicon PVs have to their advantage the fact that
there is an abundance of raw material, and, due to the maturity of this
technology, they have a long life, high module reliability, and are nearly at
their maximum theoretical effi ciency. However, developers have discovered
that silicon is not the optimal material for PV cells and it is considered
highly unlikely that the cost of this generation will ever drop below the
equivalent energy cost of fossil fuels. There is no clear solution to the high
labour and energy required for the production, again providing a barrier to
reduction in cost. Table 12.4 summarizes the effi ciency, degradation and the
advantages/disadvantages of this fi rst generation PVs for two models.
12.4.2 Second generation
The middle member of the PV family, which has been under constant
research since the late twentieth century, is the second generation solar
panel. It is considered as the smaller but fastest growing division (Brown
and Wu, 2009). It has opposite traits to the fi rst generation, and has both
lower cost and energy - essentially the two issues it was created to address,
following the shortcomings of the fi rst technology (Hamakawa, 2004). The
main reason for the difference in the two technologies is related to the
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