Is it sustainable to install solar panels north of the Arctic Circle?
Since the beginning of the eighties global solar irradiance and conditions for harvesting solar energy have been studied in the South while the far North still reminds of white spots on the map. The light spectrum is different because of longer paths through the atmosphere and more diffuse than direct radiation.
In this small Kirkenes based project several data about solar energy will be collected continuously and presented on this website soon.
The solar irradiance on the outer atmosphere is 1367 W/m² on a surface perpendicular to the sun’s rays.
The radiation gets attenuated when passing through the atmosphere. In polar regions, the length of the path the radiation must take to reach ground, is greater than at equator which leads to less energy. In addition the light spectrum is different, blue components of sunlight are scattered out of the direct beam, resulting in the exceptionally reddish-orange colours at sundown.
Here solar cells with PERC tecnologi (Passivated Emitter Rear Contact) are advantageous that reflect some of the light with longer wavelengths back to the rear of the cell for a second absorption attempt to produce additional energy.
In Northern Norway diffuse radiation has the biggest percentage of global solar radiation. Diffuse radiation has relatively higher spectral irradiances towards the short-wave end of the spectrum than the corresponding spectrum direct radiation for a clear sky.
"Heterojunction" solar cells combine to different technologies in one cell: crystalline silicon embedded in amorphous silicon thin-film, which is more efficient at shorter wavelengths.
Most part of the year the Arctic is covered with highly reflective snow.
Ordinary solar panels have a white or black back foil which is appropriate when mounted directly on a pitched roof. If the panels can be mounted free-standing, "bifacial" panels equipped with glass protection on both sides can also produce power from reflected light at the rear side.