Embodied Energy and Off-Grid Lighting, Green Tech, Page 25

PV Modules
During our analysis, we found that embodied energy data were not easily available for the small
photovoltaic modules used in off-grid LED systems. There are a number of studies (Alsema et
al., 2006, Raugei et al., 2006, etc.) that focus on “large” PV modules like the ones installed in
grid-connected systems, but smaller modules can have higher embodied energy intensity because
of their relatively lower fraction of active area and higher frame mass per watt. Figure A1 shows
a range of PV modules that are typical of those offered with off-grid lighting products. The CIS
module we focused on is labeled in the figure. Note that the fraction of active area is generally
lower in these off-grid lighting modules than with typical grid-connected PV modules due to the
use of semiconductor “seconds” (trimmings from large module wafers) and/or the setback area
between the active area and the frame.




Figure A1: Various PV modules that are typical of those included with off-grid lighting
products.

PV module primary energy requirements (PER) are composed of two primary components: the
laminate assembly (which includes cells or active material, substrates, and covers) and the frame
(Alsema and de Wild Schoelten 2006, Raugei et al. 2007, and others). In both parts, the PER for
off-grid lighting products tends to be higher than typical. The frames of modules for off-grid



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