It may be spring, but when considering solar photovoltaic power, we must also consider how systems perform in the snow, from those locations that occasionally get wintry mixes, to those places where snowfall can be expected from Halloween through Easter.
We have seen the solar photovoltaic industry grow throughout North America and now, installations are being placed frequently in snowy locations that include the northern United States and much of Canada. While there have been several unanswered questions about the effects of snow on solar cell performance, a hat trick of studies conducted by Michigan Tech University (Houghton, MI) and Queen University (Ontario, Canada) have allowed researchers to nail down the methods to determine the impact of snow on solar cells. In the first study, the team established a novel method for the determination of snowfall losses from time-series performance data with correlated meteorological observations. In the second, they look at the effect of the color distribution of sunlight reflected from snow and its effects on solar output and in the third, they try to cut the snow-related losses with surface coatings.
Joshua Pearce, a professor of Michigan Tech in both Materials Science & Engineering and Electrical & Computer Engineering, explained “The snow losses for photovoltaic systems may warrant paying to have them cleared. However, the bottom line is snow losses for most solar energy systems are much less than people worry about. Solar energy definitely works even in snowy Canada.”
The first study found losses due to snowfall are dependent on the angle and technology being considered. Pearce reported that “The effects of increased albedo (or reflection from the snow) in the surroundings of a solar energy system can actually increase the energy output by a solar array, particularly in the case of high tilt angle systems.”
The second study found that thin film solar cells made with amorphous silicon had a significant advantage for capturing sunlight off of reflected snow. “What makes this especially interesting is we can customize solar cell material selection in addition to systems design to optimize electricity output for specific environments.” explained Pearce.
Finally, in the third study, a new method to determine gains from coatings was established, but both the hydrophobic and hydrophillic coatings tested did not reduce snow-losses enough to justify the cost of coating solar panels.
Researchers concluded that even in snow, solar photovoltaic power is the way to go … for “green” consciousness as well as for renewable power resources.
The studies mentioned in this report are:
Rob W. Andrews, Andrew Pollard, Joshua M. Pearce, “The Effects of Snowfall on Solar Photovoltaic Performance ”, Solar Energy 92, 8497 (2013). http://www.academia.edu/3193083/The_Effects_of_Snowfall_on_Solar_Photovoltaic_Performance
Rob W. Andrews and Joshua M. Pearce, The effect of spectral albedo on amorphous silicon and crystalline silicon solar photovoltaic device performance, Solar Energy, 91,233–241 (2013).http://www.academia.edu/3081684/The_effect_of_spectral_albedo_on_amorphous_silicon_and_crystalline_silicon_solar_photovoltaic_device_performance
Rob W. Andrews, Andrew Pollard, Joshua M. Pearce, A new method to determine the effects of hydrodynamic surface coatings on the snow shedding effectiveness of solar photovoltaic modules. Solar Energy Materials and Solar Cells 113 (2013) 71–78. http://www.academia.edu/2937014/A_new_method_to_determine_the_effects_of_hydrodynamic_surface_coatings_on_the_snow_shedding_effectiveness_of_solar_photovoltaic_modules