The Alagón basin offers Cáceres a source of renewable electricity and energy storage

Iberdrola España has a presence in three hydroelectric plants in the basin of the Alagón River, the largest tributary of the Tagus in Spain, as it passes through Extremadura. A set of infrastructures totalling more than 200 MW of installed capacity, with the capacity to provide sustainable energy to more than 140,000 homes in our country. 

Cuenca de Alagón

Hydroelectric plants in the Alagon basin

Number of hydroelectric plants 3
Total installed capacity 204.58 MW
Number of households benefited 140.000
Year of first installation 1966

The Alagón River is the longest tributary of the Tagus in Spain, which rises in Frades de la Sierra, province of Salamanca (Castilla y León), and flows through the province of Cáceres (Extremadura) until it flows on the right bank into the Tagus river basin at Alcántara. From Iberdrola España, we take advantage of this water resource for the production of renewable and sustainable energy, in accordance with the priorities defined in the Water Act and other administrations such as the regional government, through the three Alagón reservoirs, its dams and power stations. 

Of particular note is Iberdrola España's presence in the municipality of Guijo de Granadilla in Cáceres, which has two reversible hydroelectric plants that, in addition to generating green electricity, have an efficient energy storage system: the Gabriel y Galán pumping station, located in the reservoir of the same name, and the Guijo de Granadilla plant, located in a reservoir of the same name. These two facilities, together with the Valdeobispo plant in Valdeobispo, have a total installed capacity of more than 200 MW. Hydroelectric power originating in Cáceres to supply more than 140,000 homes in Spain.

Alagón Reservoirs

The Alagón river, 205 kilometres long, collects water in its catchment area of 5,385 km2, with average flows ranging from 0.25m3/s in September to 8.5 m3/s in March. In order to promote the sustainable use of this water throughout the year, and to help mitigate the effects of drought or possible floods, the waters of the Alagón are dammed in three reservoirs, all of them in the province of Cáceres. Following the downstream direction of the river: Gabriel y Galán, Guijo de Granadilla and Valdeobispo.

Gabriel y Galán reservoir

The Gabriel y Galán reservoir is located in the municipality of Guijo de Granadilla, in the north of Cáceres. Inaugurated in 1961, it has a total capacity of 924.33** hm³ of water and an impressive surface area of 4,683 hectares (ha). Gabriel y Galán provides the community with irrigation, navigation, fishing and recreational activities in the surrounding area (all of which are regulated by the Water Law). The reservoir also includes the Gabriel y Galán gravity dam, with a crest length of 1,020 metres and a maximum height of 73 metres. The dam is owned by the Confederación Hidrográfica del Tajo.

Guijo de Granadilla reservoir

The Guijo de Granadilla reservoir, built in 1982, was constructed downstream of Gabriel y Galán to allow the integral use of the section of the river Alagón from the Gabriel y Galán reservoir to the Valdeobispo reservoir. With a capacity of 13.16** hm³ and a surface area of 124 ha, it is a turbination-pumping scheme which uses the Guijo de Granadilla reservoir as a upper reservoir and the Valdeobispo reservoir as the lower reservoir. The dam, a vault dam, has a maximum height of 48 metres and a crest length of 210 metres.

Valdeobispo reservoir

The Valdeobispo reservoir is located in the municipality of Valdeobispo and Montehermoso**, Cáceres. This reservoir has a total capacity of 53 hm³ of water and a surface area of 357 ha, and is currently a navigable area suitable for bathing.

The Valdeobispo dam is a diversion dam, from which the canal that supplies water to the Alagón irrigation area (40,000 ha) starts and, as part of the scheme for the integral use of the Alagón, it is used as a lower reservoir for pumping water from Guijo de Granadilla. The dam, of the arch** gravity type, has a height of 53 metres from its foundations** and a crest length of 142 metres**. The dam is owned by the Confederación Hidrográfica del Tajo.

(*) All the data provided on reservoir capacity and surface area come from the specialised website embalses.netExternal link, opens in new window. 

(**) Data from the Tagus production triptych.

Hydroelectric Power Plants of the Alagón River Basin

All of our hydroelectric generation plants on the Alagón river are located in the province of Cáceres, the one with the largest installed capacity being the one with the highest capacity. which has the largest installed capacity in the upper section of the basin, Gabriel y Galán, in the municipality of Guijo de Granadilla, followed by Guijo de Granadilla, also in Guijo de Granadilla, and Valdeobispo, in the municipality of Valdeobispo.

Our commitment to energy transition endorses this commitment to hydroelectric generation in the Alagón basin. An example of how to provide a renewable, clean and affordable source of energy, while adapting to the flexibility of the market thanks to storage systems, and at the same time respecting the environment and creating a significant positive impact on the region of Cáceres.

Gabriel y Galán

The Gabriel y Galán plant, located in Guijo de Granadilla, was the first of the two reversible hydroelectric plants installed in this municipality, whose group can operate either as a turbine or as a pump. In this way, it is possible to store water at times of low demand and use it to generate energy at peak times. All this in coordination with the confederation.

Commissioned in 1982, it has an outdoor location at the foot of the Gabriel y Galán dam and has a waterfall of 60 metres and an installed power of 111 MW, capable of benefiting some 77,000 homes. 

Guijo de Granadilla

The Guijo de Granadilla plant, located downstream in the Guijo de Granadilla reservoir (in the municipality of the same name) is also a pumped-storage hydroelectric plant, like the Gabriel y Galán plant, with storage capacity, outside and at the foot of the dam. Also inaugurated in 1982, Guijo de Granadilla has a 25-metre waterfall and a power of 53.4 MW, renewable energy capable of supplying almost 37,000 homes. 


In the Valdeobispo reservoir (at the municipality of Valdeobispo y Montehemoso** in the Cáceres province of Cáceres) is the Valdeobispo hydroelectric power station at the foot of the dam. Commissioned in 1966, this power station has an installed capacity of 40 MW, renewable electricity for more than 26,000 households. 

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