Page 225 - Materials Chemistry, Second Edition

214 R. Laleman et al.

Six different types of PV systems will be evaluated: Cadmium Telluride
(CdTe), CuInSe 2 (CIS), ribbon Si, multicrystalline Si (multic-Si or poly c-Si),
monocrystalline Si (mono c-Si), and amorphous (a-Si).
In the next section, we present a brief overview of the LCIA methods. In Sect.
3, the environmental impact of various PV types is evaluated using the Ecoinvent
database, which is compared with results from the literature in Sect. 4.In Sect. 5,
the impact of PV electricity is calculated and compared with other technologies’
impact. Section 6 contains the discussion and conclusions. Throughout the whole
chapter, we focus on the impact of assumed lifetime and irradiation, and the
methodology used, on the results and the perceived sustainability of PV-produced
electricity.

2 LCIA methods

2.1 Eco-Indicator’99

The Eco-Indicator assessment method (EI 99) was developed by PRé consultants
in 1999 and offers a broad perspective on the environmental impact of a good or
service (PRé consultants 2001). For this reason, many authors have used it to
analyze the environmental impact of a wide variation of products, ranging from
red clay (Bovea et al. 2007), beer (Cordella et al. 2008), water-based UV-lacquers
(Dreyer et al. 2003), desktop PC’s (Duan et al. 2009) and wind turbines (Lenzen
and Munksgaard 2002; Martinez et al. 2009a, b). Two papers, by the same author,
were found that applied the EI 99 assessment method to PV systems (Jungbluth
2005; Jungbluth et al. 2008a, b).
The EI 99 method has the advantage that the different aspects of environmental
impact can easily be visualized and summed up in one final result, namely the
‘‘eco-point’’. PRé consultants, however, advises against the use of the score in an
absolute way by stating that ‘‘The absolute value of the points is not very relevant
as the main purpose is to compare relative differences between products or
components’’ (Goedkoop et al. 2000) 1
The environmental impact of a good or service is quantified using three main
dimensions, namely human health (HH), ecosystem quality (EQ), and the deple-
tion of nonrenewable resources (R). The first step in the calculation of the overall
environmental impact score is the quantification of the impact for these three
dimensions. The unweighted results obtained in this first step are referred to as the
‘‘Characterization Results’’ and have different units. To obtain a single score (with
a single unit namely impact points or eco points), these results are normalized and
weighted (Table 2). To cope with the issue of subjectivity in the weighting step,

1
Quote from Préconsultancy report, manual for designers, page 4, http://teclim.ufba.br/jsf/
ecodesign/dsgn0212.pdf.