These observations are apparent in the referenced compilation of highest con rmed cell and module ef ciencies for many of the PV technologies.5
One key to the development of any photovoltaic technology is the cost reduction associated with economies of scale. This has been very evident in the case of crystalline silicon (c-Si) photovoltaics. Figure 4 shows the decrease in the cost of crystal- line silicon photovoltaic modules as the production rate has increased, as well as predicted future costs for both wafer-based c-Si and the emerging technologies to be discussed.6 The current cost of $4/Wp (Wp = watt peak) is still too high to signi cantly in uence energy production markets. Although it is dif cult to determine exactly, best estimates are that costs for wafer-based Si panels will level off in the range of $1–1.50/Wp in the next 10 years,7 substantially higher than the $0.33/Wp target.