Meet Rjukan, the mirror-lit city

Despite the immensity of our country, which has regions with completely different climates, we have no problems with extreme conditions. For us, snowstorms, hurricanes or earthquakes are just news stories. In addition, our position on the globe makes even the southernmost city satisfactorily sunny throughout the year.

In other countries, sunlight can become luxurious in the winter periods. This usually happens closer to the poles, but nonetheless creative solutions abound, and a Norwegian city used mirrors to illuminate a region that has the sun blocked by a mountain in the colder months.


180 kilometers from Oslo, the Norwegian capital, the small town of Rjukan does not receive sunlight for 6 months. Built deep in a valley, its geographical position makes the surrounding mountains block natural light from September to March each year.

The city was built by engineer Sam Eyde, founder of Hydro, a company known worldwide for aluminum production. The site was chosen for its facilities for the production of artificial fertilizer, combining transport infrastructure and power supply.

The best engineers and architects of the time were hired by the company, so it became known as the "city of the company." The historical relevance of the region meant that in 2015 it was awarded the title of UNESCO World Heritage.

Solar mirror

As much as some people prefer to stay away from it, sunlight is very important to our health. It helps in the synthesis of some vitamins and may even assist in preventing certain diseases.

After building the city in 1913, Sam Eyde thought of the problems that a lack of sunstroke in winter could cause residents and proposed the construction of a mirror, which he called "Solspeil", on top of one of the mountains.

That was one of the only goals he could not accomplish before his death. In 1928, however, his successor gave another solution to the problem: he chose to build a gondola that carried residents to the top of the mountain so they could enjoy the sunlight. Called Krossobanen, the vehicle works today and helps those who prefer to feel the sun directly.

Only in 2013 the mirror designed by the city's founder was built, using modern technology to direct the large reflectors. The apparatus was positioned on a mountain 400 meters above the city and redirects the sun's rays straight to the town square.

Three mirrors, with a total area of ​​51 m², form a set that can illuminate a 600 m² ellipse-shaped area in the city center. Light intensity ranges from 80% to 100% of what reaches the mountaintop, and the entire process is controlled by an automated system.

Technology is increasingly providing solutions that until recently seemed science fiction. It is amazing to realize that, even used to news, we can still be surprised by new solutions that can solve centuries-old problems.


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