Japan's Largest Mega Solar Power Plant to Be Built in Yamanashi's Hills

Yonekura-yama Solar Power Plant: One of Japan's Largest Mega Solar Facilities

A Pioneer for Solar Power Plants in Inland Areas?

It has been about a month since the Yonekura-yama Solar Power Plant, a mega solar facility of one of the largest scales in Japan, jointly planned by Yamanashi Prefecture and Tokyo Electric Power Company, began full-scale operation.

Text by TANAKA Junko (OPENERS)

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The Yonekura-yama Solar Power Plant is a large-scale solar power generation facility (mega solar) newly constructed in the Yonekura-yama hilly area, south of Kofu City. It commenced operation on January 27 and has shown a smooth start since then. This is a joint project where Yamanashi Prefecture provided 12.5 hectares of land, and Tokyo Electric Power Company is responsible for construction, operation, and maintenance, as part of the "Yamanashi Prefecture Regional Global Warming Countermeasures Execution Plan" that Yamanashi Prefecture has been pursuing since 2008. The site was chosen due to its status as one of the areas with the most sunshine hours in Japan.

The solar cells, which serve as the "source" of energy, are "CIS thin-film solar cells" manufactured by Solar Frontier, a wholly-owned subsidiary of Showa Shell Sekiyu. Compared to conventional thin-film solar cells, their energy conversion efficiency is higher. Approximately 80,000 of these solar cells, which won the Good Design Award in 2007 for their stylish, all-black design, are laid out across the hilly terrain.

With a maximum output of 10,000 kilowatts, its output is second only to the "Ougishima Solar Power Plant" in Kawasaki City, Kanagawa Prefecture, which currently has the largest output in Japan. It is the largest mega solar facility in Japan located in an inland area. The annual power generation is expected to be approximately 12 million kilowatt-hours, equivalent to the power consumption of about 3,400 average households. This is calculated to eliminate approximately 5,100 tons of carbon dioxide emissions annually, which is the amount emitted by about 1,000 average households. The power generation data is updated every five minutes and is publicly available on the Tokyo Electric Power Company's website.

The most significant feature of this power plant is that it overturns the precedent where mega solar facilities, requiring vast land, were often built on reclaimed land. It has achieved the construction of a mega solar facility in an inland hilly area, which was previously considered difficult. Since securing flat, expansive land is challenging in hilly regions, Tokyo Electric Power Company divided the site into 12 sections of varying sizes, shapes, and elevations to install the solar cells. Furthermore, by categorizing the mounting structures and other designs into several basic patterns and combining them, they avoided the increase in construction costs that would result from complex design and construction processes.

The Yonekura-yama Solar Power Plant, realized through the application of various techniques, is likely to serve as a valuable case study for constructing mega solar facilities in inland areas in the future.

Tokyo Electric Power Company (Current Power Generation Status)
http://www.tepco.co.jp/csr/renewable/megasolar/