Rjukan, a town of 3,500 people, nestles so deeply in its surrounding valley that it is completely cut off from sunlight for six months of the year.
But from this Wednesday, when the sun-tracking system for the three mirrors was turned on, its central square will be bathed in a 500 square metre patch of light for as long as the sun shines on the hills above.
"There's an electric atmosphere here," Martin Andresen, the local artist who has campaigned for the project, told The Local. "There were a lot of happy people and a lot of cameras."
To crown the event, local school children were handed celebratory sunglasses, and the town's residents played volleyball in the square.
The organisers were initially worried that the sun would not come out, leaving the international camera crews in town to film the event disappointed.
"It started out a bit cloudy today, so it was a bit tense for some minutes," Andresen said. "Now it will be a sunny winter for the first time. I'm sure people will use this lighted square for a small pause in their daily routine. It will bring a lot of new energy to the town."
Rjukan was established by Sam Eyde, who founded the Norwegian hydroelectric producer Norsk Hydro and wanted to take advantage of an enormous waterfall to produce chemical fertilisers.
From just 300 inhabitants spread out across scattered farms in 1900, the population grew to 10,000 by 1913 and the ambitious industrialist endorsed a project to deflect sunrays into the village.
"It's one of the few projects that Eyde was unable to complete, due to a lack of appropriate technology," mayor Steinar Bergsland said.
Instead he built a cable car, which is still in use, to allow his employees to recharge their vitamin D levels with sunlight on a mountain top.
The three 17-square-metre mirrors and the computer control system cost five million kroner ($849,000), which was partly paid for by Norsk Hydro, partly by the local municipality, and partly by Koro, Norway's public art body.
Viganella, a town in the Italian alps, erected mirrors in 2006 to counteract its own problems of perpetual shadow.
Andresen, who moved to the town from Paris ten years ago said he was overjoyed that his long project had come to fruition.
"I feel very rewarded, its like my little child whose going to move away from home. It's a happy day."