Solar efficiency in Norway

Materials World magazine
1 May 2018

Eivind Johannes Øvrelid talks to Khai Trung Le on work to determine how efficient solar cells can operate in rain and snow. 

As much as 98% of Norwegian electricity production comes from renewable sources. While 96.27% of renewable electricity generated is fulfilled by hydroelectricity, the affordability of solar has piqued the interest of some in Norway despite what others would assume to be poor environmental conditions in the country. However, a study from independent research organisation, SINTEF, Norway, claims that the country’s climate may be ideal.

The SINTEF team began testing solar cells in climate chambers, usually employed to test the robustness of construction materials in harsh environments, to determine their efficiency in different weather conditions, including light and heavy rain, snow, and ice forming on the panel. Ceiling lamps were installed in the chambers to simulate solar radiation to ensure consistency of illumination, and a potentiostat, a device used to control the potential between pairs of electrons, to measure the electrical output generated by solar cells under different conditions.

Norwegian University of Science and Technology student, Gina Opstad Andersen, said, ‘It was important for us to establish a reference value for solar radiation to ensure that conditions were identical during all our experiments. For this reason, we connected a solar cell fitted with a sensor that made it possible to calculate the level of radiation that the cells were exposed to in the chamber.’

The cold temperatures experienced in Norway may be beneficial to solar cell efficiency, keeping operational temperatures at low levels. High temperatures increase the internal energy leakage caused by the increased electron activity in warm weather. With silicon-based solar cells used in the experiment, output was reduced by around 0.3% for each degree of temperature increase.

Additionally, Eivind Johannes Øvrelid, Research Manager at SINTEF, told Materials World that the team is conducting tests in real world conditions. ‘We’ve had one domestic cell placed on a tilted rooftop. It’s been in place for one season. Between the weather, cold temperature, and the snow to reflect light, spring is typically a very good month for solar energy. Results have been positive.’

The SINTEF team states that the cells are also able to retain efficiency in light rain, although Øvrelid added that the cells were also unaffected by heavy rain. ‘We tested varying amounts of droplets on the cell, between 100 to a thin film of water. It had no impact on the efficiency of the cell. The solar rays simply pass straight through the rain. It had no impact on the amount of incoming radiation. The same happened when the cells were covered by a layer of ice.’

Øvrelid was drawn to exploring the efficiency of solar energy in Norway as the technology holds greater appeal to the Norwegian government, saying, ‘The government is exploring options to make newbuild homes emission-free. With the price of hydropower locked into the grid and infrastructure, and the price of solar getting cheaper, there is a greater desire for the latter in Norway.’ It may also provide surplus energy to help fulfil wider European energy demand via interconnectors.

The team has yet to publish their data, but Øvrelid intends to do so in future. Meanwhile, the SINTEF team will continue to explore other solar technologies, including bi-facial cells, as well as installing possible solar sources in Svalbard, which is still primarily powered by coal, at costs four times higher than of the Norwegian mainland.