Entracque Power Plant

Entracque Power Plant
The Chiotas Dam
Location of Entracque Power Plant in Italy
Official name	Centrale Idroelettrica Entracque
Country	Italy
Location	Entracque
Coordinates	44°13′29″N 07°23′10″E / 44.22472°N 7.38611°E / 44.22472; 7.38611Coordinates: 44°13′29″N 07°23′10″E / 44.22472°N 7.38611°E / 44.22472; 7.38611
Status	Operational
Construction began	1969
Commission date	1982
Owner(s)	Enel
Pumped-storage power station
Upper reservoir	Chiotas Plant: Lago del Chiotas Rovina Plant: Lago della Rovina
Upper res. capacity	Chiotas Plant total:30,200,000 m3 (24,484 acre·ft) Chiotas active: 27,300,000 m3 (22,132 acre·ft) (active (usable)) Rovina: 1,200,000 m3 (973 acre·ft) (active (usable))
Lower reservoir	Lago della Piastra
Lower res. capacity	Total: 12,000,000 m3 (9,700 acre·ft) Active: 9,000,000 m3 (7,300 acre·ft)
Hydraulic head	Chiotas: 1,048 m (3,438 ft) Rovina: 598 m (1,962 ft)
Pump-generators	Chiotas: 8 x 148 MW (198,000 hp) Francis-pump turbine Rovina: 1 x 133.67 MW (179,250 hp) Francis-pump turbine
Power generation
Nameplate capacity	Chiotas: 1,184 MW (1,588,000 hp) MW Rovina Plant: 133.67 MW Total: 1,317.67 MW (1,767,020 hp)
Annual gross output	Chiotas: 1,040 GWh (3,700 TJ)

The Entracque Power Plant, also known as The Upper Gesso Plant, is a pumped-storage hydroelectric power station located in Valle Gesso just south of Entracque, Italy. The power station contains pump-generators for two co-located but hydraulically separated power schemes; the Chiotas-Piastra Plant and Rovina-Piastra Plant. Both plants use separate upper reservoirs but use Lago della Piastra as their common lower reservoir. To produce power, water is released from the upper reservoirs to the power station located at the lower reservoir. The pump-generators re-fill the reservoirs and the process repeats as needed. The Chiotas' upper reservoir, Lago del Chiotas, is located much higher in the valley and larger than Rovina's Lago della Rovina which affords it the ability to produce more electricity. The installed capacity of Chiotas is 1,184 megawatts (1,588,000 hp) with a hydraulic head (water drop in elevation) of 1,048 m (3,438 ft) while Rovina has an installed capacity of 133.67 megawatts (179,250 hp) and a head of 598 metres (1,962 ft). Construction on the plant began in 1962 and operations started in 1982. It is owned and operated by Enel.

The Entracque Power Plant is supported by a scheme that also primarily consists of three reservoirs. The lower reservoir used by both the Chiotas and Rovina is Lago della Piastra. The reservoir is located at the base of the valley and was formed by the construction of an 88-metre (289 ft) tall gravity dam. Its water level has a normal operating elevation of 956 metres (3,136 ft) and 9,000,000 cubic metres (7,300 acre·ft) of its total 12,000,000 cubic metres (9,700 acre·ft) storage capacity can be pumped up to the upper reservoirs. The pumping is carried out by the power station's nine Francis pump turbine-generators, eight belong to Chiotas and one to Rovina. When either of the upper reservoirs needs to be filled, water is pumped from Piastra to the Chiotas or Rovina upper reservoirs through a series of and tunnels. This usually occurs during periods of low energy demand, such as at night, when electricity is cheap.