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SolarPV

Snow loads and snow removal at roof mounted solarPV

SolarPV is increasing rapidly in Sweden and many installations are being built in regions with regular snow coverage. Solar modules are largely mounted on roofs and can cause increased or asymmetrical snow loads for which the roof is not dimensioned in snow-rich regions, resulting in a risk of damage or collapse of the roof.

SolarPV modules can get mechanical damage from snow loads, partly obvious damage but also so-called microcracks that cannot be detected with the bare eye but still significantly lower the production. Removing snow from roof-mounted modules can be justified partly to reduce the load on both modules and underlying roofs and partly to increase production. The proposed project therefore wants to focus on three related areas:

  • Effects of roof mounted modules on the expected snow load and thus the dimensioning of roofs
  • Effects of snow load on modules in combination with module design and assembly
  • Methods for getting panels snow-free with regard to resource consumption and possible module damage

Studies of how roof-mounted solar panels can change the conditions for dimensioning roofs in different snow load zones have not been found. In the tests, a mechanical load test is performed where a homogeneous load is applied to a module in horizontal position. TÜV Rheinland has designed a lab test that simulates snow loads on angled modules. Systematic studies of how modules are loaded under real snow conditions have not been conducted. Several studies have shown that the production loss due to snow shading can be significant. Many ways to achieve snow-free modules have been proposed and some are commercialized. However, only a few methods have been tested and no comparative studies are available. Some insight into how panels can be damaged by snow load can be obtained through studies that have seen the emergence of microcracks through mechanical load tests under other conditions.

The project has four general objectives:

  • No roof damage occurs due to roof mounted modules in regions with snow occurrence.
  • Ceiling mounted modules in regions with snow occurrence have a maximum degradation corresponding to the power guarantee of 80% of initial power after 25 years normally provided by the supplier.
  • Roof-mounted solar systems have a maximum snow-related production loss of 5%.
  • Develop recommendations for how solar systems should be designed in different snow load zones that can be implemented in standards.

Find or develop at least two snow removal methods that meet the overall goals and requirements for maximum energy consumption


Summary

Project name

Snow removal methods for solarPV

Status

Active

RISE role in project

Project leader

Project start

Duration

2,5 years

Total budget

7 301 827 SEK

Partner

Lindbäcks Bygg, Länsförsäkringar Västerbotten, PiteEnergi, RISE

Funders

Energimyndigheten, PiteEnergi, RISE, Länsförsäkringar Västerbotten, Lindbäcks Bygg

Project members

Anna Malou Petersson

Contact person

Anna Malou Petersson

Enhetschef

+46 10 516 61 91
anna.malou.petersson@ri.se

Read more about Anna Malou