Okinawa Yanbaru Seawater Pumped Storage Power Station

The seawater intake/outlet faces the Philippine Sea, which serves as the lower reservoir for this power station. The upper reservoir is not shown in this picture.
Location of
Country	Japan
Location	Kunigami, Okinawa
Coordinates	26°40′25″N 128°15′56″E / 26.67361°N 128.26556°E / 26.67361; 128.26556Coordinates: 26°40′25″N 128°15′56″E / 26.67361°N 128.26556°E / 26.67361; 128.26556
Commission date	1999-05-16
Operator(s)	Electric Power Development Company
Reservoir information
Reservoir capacity	564,000 m³
Maximum depth	25 m
Lower reservoir	Philippine Sea
Power generation information
Installed capacity	30 MW

The Okinawa Yanbaru Seawater Pumped Storage Power Station (沖縄やんばる海水揚水発電所, Okinawa Yanbaru Kaisui Yōsui Hatsudensho^?) is a hydroelectric power station located in Kunigami, Okinawa, Japan and operated by the Electric Power Development Company. It is the world’s first pumped-storage to use seawater for storing energy.^[1] Its maximum output is 30 MW.^[2]

Facility

The power station is a pure pumped-storage, using the Philippine Sea as its lower reservoir, with effective drop of 136 m and maximum flow of 26 m³/s.^[2] Its pipelines and pump turbine are installed underground.^[2] Its maximum output is approximately 2.1% of the maximum power demand in the Okinawa Island recorded on August 3, 2009.^[3]

The upper reservoir, artificially excavated, lies approximately 600 m away from the seashore and approximately 150 m above the sea level.^[2] It has an octagonal planar shape with its maximum width of 252 m.^[2] Its maximum depth is 25 m and its effective storage capacity is 564,000 m³.^[2] The entire inner surface of the reservoir is covered with an impermeable liner to prevent seawater from leaking and damaging the surrounding vegetation.^[2]

Fiber-reinforced plastic tubes instead of steel tubes were adopted for the penstock and the tailrace in order to avoid seawater corrosion and adhesion of barnacles.^[1] The pump turbine is partially made of stainless steel resistant to seawater.^[1][4]

A 66 kV line connects the power station with the power grid of The Okinawa Electric Power Company.^[5]

History

The power station was a pilot plant funded by the Agency for Natural Resources and Energy and constructed by the Electric Power Development Company.^[5]. A five-year verification operation was conducted since May 16, 1999.^[1] The Japan Society of Civil Engineers presented the company an Outstanding Civil Engineering Achievement Award on May 26, 2000 for its construction of the plant.^[6] It is now under commercial operation.

References

1. ^ ^{a b c d} "沖縄やんばる海水揚水発電所の実証試験運転開始について [Verification operation started at Okinawa Yanbaru Seawater Pumped Storage Power Station]" (in Japanese). News Release. Electric Power Development Company. 17 March 1999. http://www.jpower.co.jp/news_release/news092.html. 
2. ^ ^{a b c d e f g} Shibuya, Yōko; Ishimura, Yōsuke (March 2010). "学生が行く今月の土木日本一: 世界初の海水揚水発電所: 沖縄やんばる海水揚水発電所 [This month’s civil engineering number one in Japan visited by students: World’s first seawater pumped-storage power station: Okinawa Yanbaru Seawater Pumped Storage Power Station]" (in Japanese) (PDF). JSCE Magazine 95 (3): 34–35. ISSN 0021-468X. http://www.jsce.or.jp/journal/student/nihonichi/201003.pdf. 
3. ^ "最大電力の記録を更新 (今年2回目) [Maximum power demand again hits record high]" (in Japanese) (PDF). Press Release. Okinawa Electric Power Company. 4 August 2009. http://www.okiden.co.jp/shared/pdf/news_release/2009/090804_02.pdf. 
4. ^ Fujihara, Tetsuo; Imano, Haruo; Oshima, Katsuhiro (October 1998). "Development of pump turbine for seawater pumped-storage power plant" (PDF). Hitachi Review 47 (5): 199–202. ISSN 0018-277X. http://www.hitachi.com/rev/1998/revoct98/r4_108.pdf. 
5. ^ ^{a b} Ōmoto, Kazuhiro (October 1994). "現場を訪ねて: 沖縄海水揚水建設所: 自然にやさしく [Visiting construction site: Okinawa Yanbaru Seawater Pumped Storage Power Station: Nature-friendly]" (in Japanese). Soil Mechanics and Foundation Engineering 42 (10): 47–50. ISSN 0041-3798. http://ci.nii.ac.jp/naid/110003972821. 
6. ^ "「沖縄やんばる海水揚水発電所の建設」の土木学会技術賞の受賞について [JSCE Outstanding Civil Engineering Achievement Award for construction of Okinawa Yanbaru Seawater Pumped Storage Power Station]" (in Japanese). News Release. Electric Power Development Company. 26 May 2000. http://www.jpower.co.jp/news_release/news125.html. 

See also

• Pumped-storage hydroelectricity

External links

• Okinawa Yanbaru Seawater Pumped Storage Power Station (Official site, in Japanese)
• "Seawater Pumped-Storage Power Plant". Japan Commission on Large Dams. Archived from the original on 2002-07-08. http://classic-web.archive.org/web/20020708041342/http://www.jcold.or.jp/Eng/Seawater/Seawater.htm. 
• "沖縄やんばる海水揚水発電所". Panoramio. 2008-12-31. http://www.panoramio.com/photo/17297410. 
• "The Okinawa Yanbaru Seawater Pumped Storage Power Plant". flickr. 2008-11-11. http://www.flickr.com/photos/jungochang/3044110869/.