In December 2012, TEPCO announced the operating results of a solar power generation project that it is promoting jointly with local governments. The announcement publishes data on how much power generation was at each power plant after one year of operation of the mega solar power plant. According to the presentation materials, TEPCO is currently working on three projects: two jointly with Kawasaki City (Ukishima and Ohgishima) and one jointly with Yamanashi Prefecture (Yonekurayama). . The method of calculating the expected power generation amount differs depending on the manufacturer, but it is said that each company has achieved results that exceed the expected annual power generation amount. Let's take a closer look. First, the equipment specifications of each power plant are summarized as follows. Ukishima Solar Power Plant (Kawasaki City) Solar panel manufacturer: Sharp Maximum rated output: 7,000 kWp Annual power generation (assumed): 7,400,000 kWh Annual power generation (estimated) converted to annual household consumption: 2,100 households per year Power generation (result): 9,450,000 kWh Actual power generation per assumed power generation: 1.3 times Actual power generation per 1 kWp of rated output: 1,350 kWh/kWp Ohgishima Solar Power Plant (Kawasaki City) Solar panel manufacturer: Kyocera Maximum rated output: 13,000 kWp annual power generation (assumed): 13,700,000 kWh Annual power generation (estimated) converted to annual household consumption: 3,800 households Annual power generation (actual): 15,100,000 kWh Actual per assumed power generation: 1.1 times rated output 1 kWp Actual power generation per unit: 1,162 kWh/kWp Yonekurayama Solar Power Plant (Yamanashi Prefecture) Solar panel manufacturer: Solar Frontier Maximum rated output: 10,000 kWp Annual power generation (estimated): 12,000,000 kWh Annual power generation (estimated) is generally used Converted to annual household consumption: 3,400 households Annual power generation (actual): 14,400,000 kWh Actual power generation per 1 kWp of rated output: 1.2 times Actual power generation per 1 kWp of rated output: 1,440 kWh/kWp The value exceeds the expected power generation amount. Since solar power generation is greatly affected by weather and other weather conditions, it is difficult to discuss only quantitative comparisons of rated output, installation area, cell output, and so on. Ukishima is the smallest of the three, but it has the largest actual/estimated power generation ratio of 130%. Although Ohgishima is slightly less efficient than others, it has the largest total amount of power generation. Yonekurayama can be said to be in the middle position between the two. However, the Komekurayama power plant has a distinctive feature. It is the efficiency of the actual power generation amount. The actual power generation for the maximum rated output is the top among the three sites (1,440 kWh/kWp). As mentioned above, the most likely influence is the climatic conditions of the installation site. Next, the performance of the solar panel itself is considered. Upon investigation, both manufacturers of Kawasaki City panels use solar cells called polycrystalline silicon. Yonekurayama's solar panels use compound-based cells called CIS (CIS has been widely used in satellite solar panels). What is interesting is that in general, polycrystalline silicon solar cells have higher power generation efficiency and higher output under the same power generation conditions. Even if you compare the catalogs of each manufacturer, the power generation efficiency of the single unit is more silicon polycrystalline than CIS. However, when we examine the actual amount of power generated by actually installing the solar panels on site, the CIS panels show a higher value. According to the website of Solar Frontier and NEDO (New Energy and Industrial Technology Development Organization), which had been conducting practical research on CIS thin-film solar cells with Solar Frontier, CIS panels are resistant to temperature characteristics and partial shadows. It is said that there are three characteristics that the more sunlight it receives, the more output characteristics it has. Silicon-based solar cells have the disadvantage that their output characteristics drop when the temperature of the panel rises due to exposure to light, but CIS has less drop. In addition, a silicon-based panel, which consists of multiple power-generating cells that form a single panel, suffers from a drop in output if it is partially shaded. Since the entire panel of CIS is a single cell, it is less susceptible to partial shadows. It seems that the effect that the output increases as it receives sunlight is an effect confirmed in the exposure test. Based on the power generation performance of three mega-solar power plants announced by TEPCO, we considered each feature. Although it is not possible to conclude the characteristics and performance based on the announced data, from the viewpoint of actual power generation capacity, it can be said that not only the mainstream silicon-based polycrystalline panel but also the compound-based CIS thin-film panel have sufficient performance. That's it. When introducing solar panels into your home, it would be a good idea to refer to these characteristics of mega solar power plants and select the model.
