The Longyangxia Dam is a concrete arch-gravity dam at the entrance of the Longyangxia canyon on the Yellow River in Gonghe County, Qinghai Province, China. The dam is 178 metres (584 ft) tall and was built for the purposes of hydroelectric power generation, irrigation, ice control and flood control. The dam supports a 1,280 MW power station with 4 x 320 MW generators that can operate at a maximum capacity of 1400 MW. Controlling ice, the dam controls downstream releases to reservoirs lower in the river, allowing them to generate more power instead of mitigating ice. Water in the dam's 24.7 billion m3 reservoir provides irrigation water for up to 1,000,000 hectares (2,471,054 acres) of land.^[2]

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Longyangxia Dam
Satellite picture of the Longyangxia Dam reservoir and solar power park
Location of Longyangxia Dam in China
Country	China
Location	Gonghe County, Qinghai Province
Coordinates	36°07′20″N 100°55′06″E
Status	In use
Construction began	1976
Opening date	1992
Dam and spillways
Type of dam	Arch gravity dam
Impounds	Yellow River
Height	178 metres (584 ft)
Length	396 metres (1,299 ft)
Width (crest)	18.5 metres (61 ft)
Width (base)	80 metres (262 ft)
Spillway type	Service, gate-controlled on crest
Reservoir
Creates	Longyangxia Reservoir
Total capacity	24.7 billion cubic metres (20,000,000 acre⋅ft)
Catchment area	752,443 square kilometres (290,520 sq mi)
Surface area	383 square kilometres (148 sq mi)
Power Station
Hydraulic head	122 metres (400 ft) (design)
Turbines	4 x 320 MW
Installed capacity	1,280 MW 1,400 MW (max. planned)
Annual generation	6 TWh

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The dam is composed of its main body and a gravity pier and secondary dam on both its left and right flank. The dam's service spillway contains two 12 metres (39 ft) wide gates that discharge water into two 260 metres (853 ft) and 280 metres (919 ft) long chutes. Downstream discharges are also controlled by a similar single-chute middle outlet and the lower outlet works.^[2]

In 2013 a solar photovoltaic station was built with a nameplate capacity of 320 MWp (Phase I), covering 9 square kilometres (3.5 sq mi).^[3] An additional 530 MW_p (Phase II) was completed in 2015,^[4] covering further 14 square kilometres (5.4 sq mi),^[5] making Longyangxia Dam Solar Park, with 850 MW_p capacity, one of the largest photovoltaic power stations in the world.

The solar power station is integrated with the hydroelectric power station. The park is coupled to one of the hydroelectric turbines, which automatically regulate the output to balance the variable generation from solar before dispatching power to the grid. This limits the problems connected to variable solar generation while helping to conserve water.^[4]

• List of power stations in China