More than 100 years ago, Norsk Hydro founder Sam Eyde saw possibilities in this remote farming valley of Norway, with a magnificent waterfall that could be harnessed to create electricity for large-scale industrial production of fertilizers.

In a few years’ time, the Rjukan area was home to more than 10,000 inhabitants. The valley was dark in winter, though. In fact, no direct sunlight reached the town for months on end.

On Wednesday, with media from around the world watching, the computer-controlled battery of mirrors perched in the mountains above town reflected rays down into town.

Hundreds of schoolchildren and onlookers were gathered in the town square, the lucky ones standing in the glow.

"There has been a lot of interest in the sun mirror project on the Internet," says Pål Thorud, head of Hydro's Energy operations in Telemark, "and now there are media people from around the world here - for example, RTL from Germany, TV2 from Norway, Globo from Brazil. We're not used to having the international media so interested in us! And the best thing about it all is that there is such nice weather."

Hydro's Energy business area and the local authorities in Rjukan signed an agreement on October 1 making Hydro the main sponsor of the sun mirror project.