Welcome to the Glass Age

63 (Figure 4.2 and Figure 4.3). At present, industrial thin-film solar cells, such as those based on cadmium telluride (CdTe) and copper indium gallium selenide (CIGS), have a module conversion efficiency around 20%. The progress in their efficiency enhancement has outpaced that for crystal silicon solar cells. Thanks to the application of thin film solar cells in the construction industry, BIPV has become a high- growth area around the world, especially in developing countries. As China steps up efforts to formulate its national standards of thin-film solar cells for BIPV, the importance of glass in photovoltaic application will be further highlighted. Glass for solar-thermal technology The Sun with its effective blackbody temperature of 5762 K steadily emits radiant energy, of which about 1.8x10 14 kW is intercepted by the Earth. This solar heat, captured directly or indirectly, provides the most abundant of all renewable sources of energy available for human use. Solar thermal utilization dates back to prehistoric times and it can be used extensively. Basically, photothermal conversion materials are used to convert solar radiation into thermal energy, which can then be used in industrial productions,