The Roncovalgrande Hydroelectric Plant, also known as the Delio Hydroelectric Plant, is located north of

Maccagno Maccagno was a ''comune'' (municipality) of 2,000 inhabitants located in the province of Varese in the Italian region Lombardy, located in the Val Veddasca about 70 km northwest of Milan and about 25 km northwest of Varese. On 1 January ...

in the

Province of Varese The province of Varese ( it, provincia di Varese) is a Provinces of Italy, province in the region of Lombardy in northern Italy. Its capital is the city of Varese (population of 80,857 inhabitants), but its largest city is Busto Arsizio. The head ...

Lombardy Lombardy ( it, Lombardia, Lombard language, Lombard: ''Lombardia'' or ''Lumbardia' '') is an administrative regions of Italy, region of Italy that covers ; it is located in the northern-central part of the country and has a population of about 10 ...

, Italy. Using the

pumped-storage Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing. The method stores energy in the form of gravitational potential ...

hydroelectric Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined and ...

method, the power plant has an installed capacity of . The power plant was complete in 1971 and the last generator operational in 1973. During construction, the upper reservoir, Lago Delio, was expanded in capacity with two

gravity dam A gravity dam is a dam constructed from concrete or stone masonry and designed to hold back water by using only the weight of the material and its resistance against the foundation to oppose the horizontal pressure of water pushing against it. ...

s; a northern and southern, and in height, respectively. The lower reservoir,

Lago Maggiore Lake Maggiore (, ; it, Lago Maggiore ; lmo, label=Western Lombard, Lagh Maggior; pms, Lagh Magior; literally 'Greater Lake') or Verbano (; la, Lacus Verbanus) is a large lake located on the south side of the Alps. It is the second largest la ...

, already existed. The power plant itself is located underground in between Delio and Maggiore. To produce electricity, water is released from the upper reservoir to the power plant via two long

penstock A penstock is a sluice or gate or intake structure that controls water flow, or an enclosed pipe that delivers water to hydro turbines and sewerage systems. The term is inherited from the earlier technology of mill ponds and watermills. H ...

s. At the power plant, eight four-stage

Pelton turbine The Pelton wheel or Pelton Turbine is an impulse-type water turbine invented by American inventor Lester Allan Pelton in the 1870s. The Pelton wheel extracts energy from the impulse of moving water, as opposed to water's dead weight like the trad ...

-generators generate electricity. Power generation occurs during periods of high energy demand and when energy demand is low, pumping usually occurs. The pumps are on the same shaft as the Pelton turbines and send water from the lower to the upper reservoir to serve as stored energy. Later on, this water will be sent back down to the power station and the process will repeat. The difference in elevation between the upper and lower reservoirs affords a

hydraulic head Hydraulic head or piezometric head is a specific measurement of liquid pressure above a vertical datum., 410 pages. See pp. 43–44., 650 pages. See p. 22. It is usually measured as a liquid surface elevation, expressed in units of length, ...

of and Lago Delio has a usable storage capacity of .

References

{{reflist Dams completed in 1971 Energy infrastructure completed in 1971 Energy infrastructure completed in 1973 Dams in Italy Hydroelectric power stations in Italy Pumped-storage hydroelectric power stations in Italy

See also

References