Solar Development in Northern Latitudes
Snowlar Builder: We look at the opportunity of solar development in Northern latitudes
February 14, 2019
This article is posted with permission from Solar Builder Magazine.
Solar power is starting to bolster the energy capacity in northern climes, especially across Canada and Alaska where diesel generators take the cost of electricity sky high. Both fixed-tilt and tracker installations are expanding rapidly in this region, as advancing solar technology helps cope with bitter cold and erratic daylight.
The sun can be elusive in the north. Between the spring and fall equinox, the Arctic region — including Fairbanks, Alaska, at a latitude of about 65 degrees — receives over 12 hours of daylight, but during the long winter sunlight can fall to only 10 percent of the summer peak. The extremes for the length of an Arctic day can range from 3.5 hours in winter to 22 hours in summer.
The combined potential of direct and indirect or diffuse light available in the north is enticing though. Research cited by the Alaska Center for Energy and Power (ACEP) indicates that there are 230 more hours of possible sunlight at the Arctic Circle than at the equator. The winter holds a steady snow blanket on the ground, yielding one of the highest natural levels of albedo, or reflected light, at 70 to 80 percent of direct sunlight. This bodes well for the use of bifacial solar panels, which today can raise the energy yield by around 10 percent with more field testing expected to increase the bifacial boost by 20 percent or more over monofacial panels.
“We are not under any illusions that solar will not be a tough build, but cost has come down, so now it finally pencils out,” says Christopher Pike, a researcher at ACEP.
Thanks to the general decline in the cost of solar and the recent cost reduction in bifacial panel manufacturing, solar is becoming a more promising renewable energy solution in the northern latitudes. Indeed, one estimate of solar growth in Alaska suggests that installations roughly doubled during 2017 to close to 1 MW from a small base of about 300 kW in 2016, according to the Solar Energy Industries Association (SEIA). Anecdotes from Alaska solar analysts suggest that the 2018 installation total could double again.
Design and conquer
The far north is a virtual testing ground for solar reliability, particularly for trackers with moving parts, and chatting with several manufacturers focused in this region reveals a variety of tactics for conquering the elements.
“If you see a tracker system in the Arctic controlled by actuator arms that can freeze, or fragile motors or sensors, it can be a concern,” notes Lance Brown, the director of marketing at Array Technologies. “But we are seeing more and more requests for installations at higher latitude locations.”
Array did a dual-axis project in the Arctic for the Canadian government 20 years ago for a 360-degree tracker, and it is still operating now, designed to function down to -25.6 degrees F, Brown says (new trackers are tested to -29.2 degrees F). Array is currently working on a new snow stow technology that will further optimize tracker performance in heavy snow conditions. Dealing with snow load is a primary requirement in the north.
“We have installed our dual-axis Savanna in heavy snow areas in northern Ontario and have had no issues with snow load,” says Nic Morgan, VP of business development at Morgan Solar in Toronto. “We found that the dual-axis sheds snow faster than fixed or single-axis designs. We can’t compete with single-axis trackers below 40 degrees latitude, but above that, dual-axis technology can offer better yield.”
One area of expertise that Toronto-based GP JOULE has developed in the cold Canadian climate is foundation engineering, with a current single-axis tracker design that utilizes up to 60 percent fewer piles — or as few as 250 per MW — than general U.S. tracker competition, providing 20 percent more steel and a more robust structure, says David Pichard, CEO of the company. The system also uses up to 20 percent fewer piles than a competing standard fixed-tilt design. Click here to read the complete article