A group of scientists from the Norwegian University of Life Sciences, the University Centre in Svalbard, and Norway-based consultancy Multiconsult, has sought the assess the technical feasibility of large scale PV projects in polar regions and has investigated, in particular, the performance of a small-scale, ground-mounted, solar array in the Adventdalen valley in Svalbard, which is a Norwegian archipelago in the Arctic Ocean located halfway between Norway and the North Pole.
The small facility was south oriented and built with the panels having a tilt angle of 30 degrees. The module rows have a distance of 5.5m and the panels are placed at a height of 1.3m. Timber poles with a length of 12m are used as ballast to protect the arrays from high wind speeds.
The fixed-tilt installation relies on an off-grid inverter provided by California-based specialist CyboEnergy and several 265 W monofacial modules of type JKM265P, provided by Chinese manufacturer JinkoSolar. The panels were installed on a wooden rack in opposite directions, with some facing the sky and some facing the ground. “A bifacial module was installed as well but was covered by the snowdrifts during the beginning of the production season and suffered significant power production losses,” the researchers specified.
Solar power generation was registered only between March 5 and October 19, when the region was hit by enough sunlight to make the facility go into operation. From mid-November to mid-January, there isn't any sunlight at all in the area.
When tests were performed, the scientists observed snowdrifts forming on the leeward side of the plant, and saw that these melted entirely between the winters. “The results show an increase of drift length, height and volume with the time of exposure in the field,” the Norwegian group explained, noting that accumulation mainly occurs at the leeward side of the PV array, which is the side that faces away from the wind.
The snowdrifts on the plant, they further explained, are similar to those produced by porous snow fences. A snow fence is an artificial barrier that forces wind or drifting snow to accumulate in a desired place. “The similarity indicates that snow-fence theory can be applied to PV arrays and used to control snowdrift accumulation in solar power plants,” they also stated. “The design can be adapted so that snow is deposited in designated areas (as with snow fences) or so that the deposition is minimized.”
Furthermore, the academics found that snow accumulation can also be lowered by shifting the azimuth, array tilt, and bottom gap of the PV array. “However, the influence of the rack itself should be taken into account in such cases,” they emphasized. “The finding also indicates that if the attack angle in the field measurement set-up was 90 degrees instead of 30-45 degrees, the length and cross section area of the snowdrifts could increase by up to 50%.”
Their findings can be found in the paper Polar solar power plants – Investigating the potential and the design challenges, which was recently published in Solar Energy.
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