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Snow on Solar Panels Removed During Night to Increase Power Generation (1)

Service charges determined according to increase in power generation

2019/05/02 18:32
Shinichi Kato, Nikkei BP Intelligence Group, CleanTech Labo
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A new snow removal method is being discussed for O&M (operation and management) of solar power plants in snowy regions. The method is to remove snow from solar panels at night when power is not generated to avoid power generation loss in daytime the following day (Fig. 1). If the increase in the power generation amount is expected to exceed the snow removal cost, the method will be beneficial to both power producers and snow removal companies.

Fig. 1: Snow accumulated on solar panels (source: Golden Leaf-Works)

The number of solar plants that are in snowy regions and include snow removal in the O&M services is limited because two measures against snow accumulation are incorporated in the design.

One of the measures is to increase the installation angle so that snow accumulated on panels slides down easily. The other is to set the installation height high so snow that slides down panels and accumulates on the ground avoids contact with the bottom of panels. Situations that significantly reduce power generation volume for a long period are avoided by these measures in many cases even if panels are covered with snow temporarily.

Therefore, only a limited number of solar power plants carry out snow removal on a daily basis (Example of a solar power plant in the inland area of Yamagata Prefecture). However, they request snow removal when snow accumulation continues for a longer period than usual.

Daily snow removal at solar power plants in snowy regions drew attention in the winter of 2017/2018, when record high snow accumulation occurred in the coastal regions along the Japan Sea. This resulted in roads, railways and other transportation facilities being closed for a long period in many regions.

Accumulated snow nearly reached the bottom of panels at solar power plants and snow remained on panels for a long period without sliding down, resulting in significant power generation loss at many sites. Furthermore, the weight of accumulated snow far exceeded the design value and solar panels and mounting systems were damaged throughout an extensive area.

Following the heavy snow, some solar power plants began to remove snow on a daily basis. When snow accumulation exceeds a certain height, companies that offer snow removal services send staff to solar power plants to remove snow from the spaces between arrays (units for fixing solar panels on mounting systems) including the areas below the bottom of panels, for example (Fig. 2).

Fig. 2: Examples of snow removal at solar power plant in Hokkaido (source: Golden Leaf-Works)