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19.5MW Solar Plant Arranges Panels on Slopes (page 3)

Steel molds improve foundation accuracy, shorten construction time

2014/03/08 22:26
Shinichi Kato, Nikkei BP CleanTech Institute
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At this mega-solar power plant, however, the land gets lower as it approaches east. To make elongated concrete foundations stretching south to north and keep the same height in the same row stretching east to west, the problem of maintaining the same height for each foundation would increase.

Based on these circumstances, Daiwa House Industry boosted the accuracy of vertical heights by making concrete bases for even panel heights like bridge beams at both the east and west ends in advance, and forming elongated concrete foundations that align east to west using metal molds that bridge those bases at both ends. The dimensions of the concrete foundations vary according to the wind pressure that the solar panels would be subject to in the mega-solar power plant (Fig. 9).

Furthermore, metal molds were adopted for the creation of these concrete foundations (Fig. 10). Wooden frames are generally used when pouring concrete. The conventional method, in which craftsmen assemble the wooden frames and place concrete, faces the challenges of maintaining accuracy and shortening the construction period because the wooden frames would be mostly handmade one by one. On the other hand, the benefits of using metal molds include the fact that they do not require mold and rebar experts to handle them and that they can be constructed in a shorter period of time due to higher dimension accuracy.

As the molds included some that use high-priced steel called H-shaped steel (Fig. 10 left), the material cost rose. Daiwa House Industry said, however, it succeeded in absorbing the cost increase throughout the entire plant, boosting construction efficiency by leveraging the large scale (where a large amount of solar panels, that is, as much as 22.9MW, was to be arrayed) and making the foundations in series block by block.

As to weeding, weed control sheets will be adopted at the 16.0MW output mega-solar power plant in accordance with the verification of several weed control measures at the 1.6MW and 1.9MW output power plants that were completed earlier. In addition, to help make the view of inorganic solar panels spreading like the sea give the impression of blending in with the surrounding environment as much as possible, clover, which could function as a weed control measure, will be planted across the 16.0MW mega-solar power plant.

Korean LG Electronics Inc's solar panel and Toshiba Mitsubishi-Electric Industrial Systems Corp's (TMEIC) PV inverter were adopted. The total output of the three power plants is 19.5MW, but about 22.9MW of solar panels were installed.

At the 16.0MW output mega-solar power plant, in particular, the space between the solar panels was narrowed to increase the number of panels that could be installed. As a result, for a few hours during the day, some panels are shaded by their adjoining panels on their south side. Daiwa House Industry explained that it adopted this design, finding out that the effect would be larger in the amount of power generation increase by setting up more solar panels, compared with the amount of decrease by the shadow over the panels.