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Rjukan is a town in the Tinn Municipality of Norway. It is located about 180km to the east of the capital city of Oslo and sits at the bottom of a deep valley between the lakes of Møsvatn and Tinnsjå. The town has a population of about 3000 people and covers 260 hectares.

Originally called Saaheim, the town was developed by Norwegian industry – the hydro story being central to its inception. Rjukan was built by Hydro´s founder Sam Eyde at the beginning of the last century. Eyde was instrumental in harnessing the power of the 100 metre Rjukanfossen waterfall to generate hydro-electricity. He pioneered new technologies to produce saltpetre by oxidising nitrogen from air, and made industrial quantities of hydrogen by water electrolysis. The town was planned by Norsk Hydro, with the best architects and engineers of the time, to create a so-called “company town”.  During this time, the population was just over 8000.

Diagram – Reuters

Reuters-Tore Meek-NTB Scanpix

After 1960, most of Norsk Hydro’s saltpetre production in Rjukan was transferred to other factories in Norway and the population decreased.

Rjukan is in a valley running east to west with the towering Gaustoppen mountain (at 1883m above sea level) on one side and steep mountains immediately to the south. For six months of the year, from late September to mid-March, with the low placement of the sun in Winter, the town sits in a complete shadow during this time.

In 1913, Eyde had the idea of a “Solspeil”, or Sun Mirror, above Rjukan to give the local people, who were mostly staff of the factories, some sun. Although his initial idea never came to fruition due to technology at the time, 100 years later local resident and artist, Martin Anderson worked on a project to make it happen.  In October 2013, the construction of a system of mirrors to deflect the sunlight down into the town square was completed.

The Solspeilet has been installed on the mountain wall at 742m above sea level, and about 45m above the Rjukan market square. The sun mirrors are a computer-controlled mechanism of three giant mirrors powered by solar and wind energy, that direct sunlight down from the mountaintop. The mirrors are programmed to move with the sun, readjusting every 10 seconds to keep a constant beam of light reflecting down upon the town. The sunlight is deflected to the market square in an ellipse shape of about 600m2.