In 1894, the first Portuguese hydroelectric power station became operational in Vila Real on the initiative of the remarkable Karl Emil (Emílio) Biel, a German businessman, publisher, and photographer settled in the city of Porto. The hydroelectric station, locally known as “Central do Biel”, remained in operation until 1926.

In 1932, José Pires Granjo, a local industrialist, acquired the property. He expanded the facilities to establish a tannery on the site, taking advantage of the former power station structures and thus preserving most of its 19th-century machinery. At that time, the area around the old hydroelectric station became known as “Quinta do Granjo” (Granjo’s Farm).

The tannery closed in the mid-1950s, but there must have been some hope of a reopening, as the manufacturing unit’s operating licence was kept active until 1966. From then on, it underwent a gradual process of neglect and decay, which would be reverted in 2017, with the classification of the whole site as a Property of Municipal Interest and the subsequent revitalization works, concluded in 2024.

The hydroelectric power station was built on the left bank of the Corgo river — in a place formerly occupied by ancestral water mills, of which some archaeological evidence remains — near the Agueirinho Waterfall, so as to take advantage of a natural slope of about 25 meters. Due to its size, the waterfall became a favourite motif for many photographers since the 19th century. One of them was Karl Emil Biel himself, who photographed it for the first time in 1892. From a geomorphological point of view, the exuberant terrain is dominated by cliffs standing on granites, which are over three hundred million years old.

At the top of the waterfall, a masonry dam was built, connected to a diversion channel with 68 meters in length and a maximum height of 11 meters. From this channel, the water was led downwards into the turbine shaft through a 30-meters long iron pipe with a 1-meter diameter.

The power station’s main building comprised the turbine shaft, the engine room, and the operator’s quarters, as well as an entrance vestibule. The ground on which it stands was partly reclaimed from the river by means of a seven-meter-high granite masonry wall. The hydraulic motor set up at the Biel Power Station is a German-made Knop turbine. Under the masonry arch facing the river, this hydroelectric turbine — the earliest in Portugal — is still preserved today. In the engine room, the main power transmission shaft was installed, as well as the automatic turbine regulator, two dynamos, and the electrical panel that controlled the distribution of electricity throughout the different neighbourhoods in Vila Real.

The old path leading to the mills that once stood along the riverbank was reused in the late 19^th century to serve the power station, with some flights of granite stairs added, and several flagged stretches of its original configuration, probably dating back to the early modern period, were thus preserved.

In addition to the first Portuguese hydroelectric power station, several structures within its surrounding area were musealized, including old paths and various elements of folk architecture that are characteristic to the Douro Demarcated Region, in which Quinta do Granjo is located. The restorative works resorted as much as possible to the techniques and materials originally used.

Today this restored cultural heritage site takes on a unique significance, especially within the context of industrial archaeology. The unusual features of the surrounding landscape and natural environment have also been considered in the renewal project of the old Biel Power Station and Quinta do Granjo, so as to meet both museological and ecological concerns.