The photo is sourced from pv-magazine.com
The facility consists of heterojunction solar panels mounted on vertical racks supplied by German manufacturer Next2Sun, and of an inverter manufactured by Japanese company Omron. The installation will convert direct current into alternating current with a change in voltage. The upright structure will increase the efficiency of electricity generation in winter by reflecting snow, and in summer it will provide for an economy of space, which is important for crop producers. An installation possessing such useful qualities will surely find its application in other regions of Japan as well. According to PV Magazine, Luxor Solar KK is planning a similar project in Hokkaido, Japan’s northernmost island, where snow depths are even greater than in Niigata Prefecture.
The heterojunction panel technology was developed by the Japanese SANYO, which was later acquired by Panasonic. In the 1970s, SANYO specialists began coating photovoltaic cells with amorphous silicon (a-Si), which is used in manufacturing of mini calculators. This provided for a sharp increase in the range of sunlight absorption. However, the new technology had a considerable drawback, namely, the low efficiency of solar energy conversion, which did not exceed 13.6%. This limitation was overcome when manufacturers started to laminate a-Si cells with crystalline silicon wafers and a thin transparent electrode layer. As a result, the efficiency of heterojunction panels exceeded 20%.
The advantage of heterojunction batteries is their resistance to extreme temperatures. For instance, this year the Chinese Hausun developed a completely black heterogeneous panel that can operate at temperatures ranging from 40 degrees Celsius below zero to 85 degrees Celsius above zero. When this temperature range is exceeded by 1 degree Celsius, the efficiency of such a battery decreases by mere 0.26%, while for conventional silicon batteries, the temperature coefficient ranges from 0.3% to 0.5%. These properties allow the use of the heterojunction technology both in cold and hot countries.
