A Data-Driven Review with Case Studies and Scientific Context
1) Introduction
Photovoltaic (PV) systems deployed at high latitudes face unique climatic stressors:
frequent freeze–thaw cycles, low ambient temperatures, snow cover and highly
variable irradiation throughout the year. These factors influence both electrical
performance and long-term degradation pathways of PV modules. A recent overview of
cold-climate PV sites can be found in the study “Long-Term Photovoltaic System
Performance in Cold, Snowy Climates”.
2) Actual Understanding of PV Degradation in Cold Climates
2.1 Field-Derived Degradation Rates
Recent research compiling multiple cold-climate sites (Köppen Dfb, Dfc, ET
classifications) shows that observed annual degradation rates often peak around
−0.1% to −0.2% per year, with tails extending to around −0.5%/y in harsher
environments. Many northern plants with at least three years of high-quality data
display median degradation significantly lower than typical temperate-climate
benchmarks. A concise summary of this pattern is discussed in the article “PV modules
degrade less in Nordic climates” (PV Magazine).
In other words, high latitude does not automatically mean “faster PV decay”. The
environmental stress spectrum is simply different: more wind, ice and snow loading,
less continuous high-temperature stress, and a different seasonal distribution of
irradiation.
2.2 Mechanisms in Focus
Key degradation and loss mechanisms for deployed systems in cold regions include:- Soiling and snow blockage, where accumulated snow and ice physically block
irradiance until it slides off or is removed. An accessible general overview of soiling is
available in the entry “Soiling (solar energy)”.- Potential-induced degradation (PID), driven by leakage currents and surface charge
imbalances in crystalline silicon modules, which can be influenced by moisture and
long-term system voltage. A general explanation is given in “Potential-induced
degradation”.- Thermal stress from repeated freeze–thaw cycles, which can accelerate microcracking
in cells, fatigue in solder joints and long-term embrittlement of encapsulants.
These mechanisms interact with each specific site: mount type, orientation, snow
clearing strategy and local microclimate all matter.
3) Case Examples: Nordic and Canadian Installations
3.1 Nordic Observations
A Norwegian field study on systems near 60–61°N reported module degradation in the
range of 0.1–0.19% per year – substantially lower than the ~0.5–0.6%/y global average
frequently quoted for conventional climates. This finding is summarized in the same PV
Magazine article mentioned above (pv-magazine.com).
The takeaway is simple: cold climates do not necessarily worsen intrinsic module
degradation. In certain conditions, cooler cell temperatures reduce thermal stress and
UV-driven degradation compared to hot desert or rooftop environments.
3.2 North American Subarctic Sites
Analyses of PV arrays in Alaska (~65°N) and Northern Canada (~62°N) show
degradation values that vary across a broad range, but often cluster around a median
close to −0.33% per year when enough high-quality years are available. While
electrical degradation remains moderate, snow, ice and mechanical loading emerge as
the dominant uncertainties. A more detailed discussion appears in the IEA PVPS Task
13 report on soiling and snow losses (IEA PVPS T13-21:2022).
4) Implications for Northern Europe and Finland
Finland’s latitude – including regions close to the Arctic Circle – creates an annual PV
profile with very short winter days and extremely long summer daylight. Low winter
sun angles and snow cover shift how energy is produced and how systems should be
designed. A context overview is given in the article “Solar energy in Finland”.
For developers and investors, this has several implications:- The energy yield is strongly concentrated in the snow-free season, even if some
winter production occurs.- Albedo from snow can, in some configurations, slightly boost yield in early spring.- Vertical or steep-tilted installations are increasingly explored to better capture low
sun angles and minimise snow accumulation.
From a financial and reliability perspective, planning must explicitly include interannual
irradiation variability, snow obstruction periods and realistic winter maintenance
strategies.
5) Practical Cutter for Developers and Owners
From a practical Greenconexa-style viewpoint, the main lessons for Nordic projects are:- Design structurally for snow and wind loads; mechanical certifications and local
engineering are as critical as module datasheets.- Expect relatively low intrinsic electrical degradation but potentially higher mechanical
stress impacts over time.
- Model annual energy yield using climate-specific datasets instead of generic
“European” values.- Include operational budgets for seasonal soiling and snow management in O&M;
planning.
In short, the North is not an enemy of PV – it is simply a different game board, where
structural robustness and realistic expectations matter more than headline efficiency
percentages.
6) Key References- “Long-Term Photovoltaic System Performance in Cold, Snowy Climates” – overview on
ResearchGate: link.- “PV modules degrade less in Nordic climates” – PV Magazine article: link.- IEA PVPS Task 13 report on soiling and snow losses: link.- General context: Solar energy in Finland, Soiling (solar energy), Potential-induced
degradation:PVGIS – Homepage: https://joint-research-centre.ec.europa.eu/pvgis_en - PVGIS SARAH: https://joint-research-centre.ec.europa.eu/pvgis-sarah_en
- PVGIS PV Estimator: https://re.jrc.ec.europa.eu/pvg_tools/en/
- NRCan – Solar Photovoltaic Info Hub:
- https://natural-resources.canada.ca/energy/renewable-electricity/solar-photovoltaic
- NRCan – PV Performance and Reliability Research: https://natural-resources.canada.ca/energy/re
- newables/solar-photovoltaics/photovoltaic-pv-research
- CanmetENERGY Ottawa: https://natural-resources.canada.ca/canmetenergy-oan
- CanmetENERGY Varennes: https://natural-resources.canada.ca/canmetenergy-varennes
- NREL – PV Module Degradation Study: https://www.nrel.gov/pv/cell-and-module-degradation.html
- IEEE – PV Reliability in Cold Climate: https://ieeexplore.ieee.org/document/7421545
- Sandia Labs – PV Aging & Degradation: https://energy.sandia.gov/photovoltaic-reliability/
- FMI – Solar Radiation Data: https://en.ilmatieteenlaitos.fi/solar-radiation
- FMI – Climate & Weather Statistics: https://en.ilmatieteenlaitos.fi/statistics
- Solar Energy Laboratory – Wisconsin-Madison: https://sel.me.wisc.edu/
- ESTI – European Solar Test Installation:
- https://joint-research-centre.ec.europa.eu/european-solar-test-installation-esti_en.