Mills in Alto Aragón - central eléctrica


Laguarta, though quite a remote spot in the Valle de Serrablo, is easily found. From Boltaña take the road towards Lanave. It is scenic, narrow, winding, and long. Take care. First the road goes up to the Puerto de Serrablo and then slowly goes down into the valley. You'll pass the sign for Matidero, cross the very young river Alcanadre, then Guarga and eventually reach Laguarta. Drive through the small village and halt at the other side near the coloured waste containers. It is also the spot where the rivulet Barranco de San Salvador crosses the road. Walk the path along the water. The mill is located only a few steps up stream.

Pictures: 10.iv.2007, 31.v.2023

(1) The small Fábrica de Electricidad (power plant) of Laguarta — 2007

Saturday, October 7th of 2006 was a great day for the dozen of people living permanently in Laguarta. It was then that —with much pump and circum­stance— the new powerline was officially put in service. The village was ready for the twentyfirst century. Life would become much easier.

Some people even played with the idea of a reope­ning of the albergue which was closed many years ago precisely because there was no electricity. But from now on it should be possible to lure at least some tourists to the village.

The locals kept their cool though. They knew already that it would take a long time before the new commodity could be trusted to flow without hiccups. The old installation would be kept in working order as a backup for several years to come

Up until 2006 electricity came from this humble building (1) which at the time of our first visit had Central painted on its door. Two lines, just above a man's height (4), run to the nearest house and provided barely enough energy to make it possible to leave the home during dark winter nights, states a news­paper article relating the inauguration.

(2) Mill with pressure pipe — 2023.
(3) Wiring and street lights old and new — 2023.

This humble power station has a long and interes­ting history which can be read on the website of the village (). The story is told in Spanish and I will therefore repeat some of the main points in English. The entire translation is available for download (PDF, 150 kB).

It all started in 1914 when Mr. Juan Urrutia Zulueta was visiting Laguarta, and stayed at Casa Cudillo. He was the repre­sentative of the company Hidroeléctrica Ibérica (#). His visit was about the construction of a high voltage line which would connect the projected hydroelectric power plants of the Cinca River basin with the industrial zone of Bilbao, which was in full development and would soon need cheap electricity. The distance to cover was more than 400 km: a challenge for the time (¥). The best path for this line passed through Laguarta, and therefore prior authorization from the affected owners was required.

The project was explained during a meeting in Casa Cudillo (home of Mr. José Villacampa). It was difficult to convey what electricity exactly was, because at that time people knew only about candles, torches, or oil lamps. But a demonstration was given with a dynamo mounted in a wooden box complemented with two light bulbs and it was an afternoon full of wonder for the people present, who formed the Society of Owners in Laguarta.

The Society of Owners of Laguarta explained that there was no problem to place the poles and facilities in the fields and mountains of the village. However as compensation they also wanted the so-called bujías (light bulbs) in their houses to light up the night. However, this was not feasible, they were told, the costs would be too heavy. The members present failed to understand how people in Bilbao would enjoy lighting and not the people in Laguarta. After several negotiations, in which Mr. Villacampa mediated, an agree­ment was reached. Hidroeléctrica would design a small hydroelectric power plant for the locality and they would also help with the purchase of materials. The Society of Owners of Laguarta would provide labor and make up for the rest of the cost.

(4) Insulators above the door of the central
(5) Drain of the turbine

During the following year, the local situation and possibilities and wishes were studied and eventually in May 1916 an engineer of Hidroélectrica presented the Project to the Society of Owners. The owners agreed unanimously that the construction of the Power Plant and the complementary services would we carried out.

To make execution of the plan possible, several things where agreed upon:

(6) The mill pond; overflow is left; inlet at center foreground— 2023

More decisions were taken:

(7) The mill pond; inlet and overflow top left; grate protecting the pressure pipe at right — 2023

Work began in the spring of 1918, starting with the improvement of the irigation channel, the pond, the construction of the shed and erection of the posts.

The mill pond consisted (just like today) of a stone wall about 8 m tall, oriented to the south. It counts two outlets. One is the overflow drain (6, 7) at the top of the wall. The other is situated 1 m above the bottom (currently at the bottom): it is the intake for the pressure pipe (8).

The water supply for the mill is integrated in the irrigation system. The pond is filled during the day and at night this volume is used to produce electricity. The overflow, once the pond is full, is then used for irrigation. There was a connection with the ditch for irrigation, which came from the source of the river Guarga, about 800 m away from the pond. Nowadays this ditch belongs to the municipal council and feeds the deposit for the drinking water of Laguarta. The connection between both systems is severed.

(8) The mill pond; grate protecting the pressure pipe at right — 2023

The turbine was made in 1917 at the Ebro foundry in Zaragoza and was labeled Ebro 125 (§)

The electric generator was a model from the AEG factory brought from Germany. The generator ran at 1400 revolutions/minute and originally generated 230 V, which at 16.5 A gave a power of 3.8 kW. The original voltage was transformed down to 150/125 V at the output. The regulator allowed a maximum output of 150 V, which dropped to 125 V in the houses due to the resistance of the unprotected copper line.

The entire system counted 100 light bulbs in the village, plus 2 in the power station itself. In the initial layout of 1918, Casa Cudillo and Casa Lorente had an allowance of 12 bulbs each (in accordance of the agreement) and the rest of the houses of owners each 5. Leaving a total of 16 light points for those who were not from the Society (i.e. the school, baracks of the Guardia Civil, the abbey, …). This configuration would change over time due to changes in the requirements (f.e. more light bulbs, public lighting) ().

(9) The ditch with the village in the depth — 2023

On 24 May 1918, the official inauguration took place and the installations were blessed by the priest.

Around 9:00 p.m., the grid was officially connected and as a demonstration people were allowed to light 4 bulbs per house. A test carried out some days earlier had shown that if more than 100 bulbs were switched on then the fuses of the central would blow.

Eventually, to ensure correct operation, a fuse was installed in each house, which would jump if all bulbs in that house were switched on at the same time. In Casa de Cudillo and Lorente the limit was 400 W, in the rest of the 12 houses 150 W and in the others 100 W each (). Which added up to a maximum theoretical power of 3.1 kW.

But many times there were problems and the system need continual adjustment, because there was not enough water to reach the maximum possible production. With the pond full and a maximum consumption of 2.5 kW, there was in principle enough water for four hours of lighting. Then, if there was a need for more, the irrigation water could be redirected. This meant that in winter there was electricity until 10 in the night and in summer until 12 at night, all depending the amount of water available.

(10) The watersupply ditch — 2023.
(11) The pressure pipe — 2023.

The Power Plant stayed in use until 2006 when Laguarta finally was connected to the wider grid. Light came from then on at 220 V like everywhere else. It is ironic that they, being the first to have in electricity more than a century ago, ended up one of the last villages to be connected to the grid. The old system was kept in good working order as a backup and for educational purposes.

In 2018, the installations were heavily damaged as a result of work on the high-voltage line. At the time of writing, the system is still unusable. How ironic, and regrettable, that the line that gave rise to this exciting venture also marked its end.

Pedro M. Marín Casanova — 2018 — 100 Años de Central Eléctrica en Laguarta. — — website visited 26.x.2021
# Hidroeléctrica Ibérica was founded on 19 July 1901 for the production, transportation and supply of electrical energy in the Basque Country. In 1922, after having obtained new concessions on the Cinca and Cinqueta rivers, it put the first group of the hydroelectric plant in Lafortunada into operation.
¥ Hidroeléctrica Ibérica had been the first company to adopt 30 kV voltage for its energy transmission lines and in 1923 the first to use the 132 kV voltage in Europe, after putting the transmission line from Lafortunada to Bilbao into service. This same high voltage line appears also in our page about the Molino del Azoguillo in Puente la Reina de Jaca.
If we take into account the average wage in Spain of the time (2 Eurocents) compared with the average wage in 2021 (113.77 Euro) and taking an exchange rate of 1 Euro = 166.386 Pesetas (2002), then this investment of 960 Ptas is the equivalent of nearly 33 000 Euro today. In my opinion those families must have been very rich.
The data are based on: Leandro Prados-de-la-EscosuraWhat Was Spain's GDP Then ? — MeasuringWorth, 2023 — URL: — visited on 01.vii.2023
§ The full name is S.A. Maquinista y Fundiciones del Ebro. The company was founded under the name Sociedad Bressel y Pellegero in 1911 in response to the needs of the sugar industry. The founders were Alberto Bressel (German nationality) and José Pellegero. The name was changed in 1918. The company ended its activities in 1989.
Nueva España in its edition of 19.xi.1977 publishes a list of las centrales eléctricas del Altoaragón and gives their capacity in the year 1976. The plant of Laguarta is listed with a power of 8 kW.
 The bulbs which were used consumed 40 W probably. That was a common type at the time.

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