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Solar panel

Eberhardt Josué Friedrich Kernahan and Enrique Rodríguez Cañas

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Scanning electron micrograph of a crystal of copper indium gallium diselenide, or Cu(In,Ga)Se2 (commonly abbreviated to CIGSe or CIGS). CIGS is a semiconductor used to make thin-film solar panels, as it converts sunlight (solar energy) into electricity very efficiently. Thin-film solar cells and modules based on CIGS are also very durable outdoors. Solar energy is one of the most abundant and cleanest renewable energy sources currently available. Using renewable energy sources reduces dependence on fossil fuels and helps to protect the environment. This image has been digitally coloured. The width of the image is 320 micrometres (0.32 mm).

How do thin-film and traditional solar panels compare?

Traditional silicon solar panels are between 11 and 23 per cent efficient. In contrast, commercially available thin-film solar panels are currently between 9 and 15 per cent efficient, but up to 21 per cent efficiency has been achieved in a laboratory. Both types of solar cells have lifespans of around 20 to 25 years. Traditional silicon solar panels are made from either monocrystalline or polycrystalline silicon. Solar cells made from monocrystalline silicon are more efficient than both polycrystalline silicon and thin-film solar cells, but cost approximately 30 per cent more. The main advantage of using thin-film solar panels is that they are lightweight and flexible, which makes them easier to handle and install and allows them to be integrated directly into the roof of a building.

Do solar panels work when it's cloudy?

Yes they do! Traditional and thin-film solar panels work on both sunny and cloudy days as well as in rain and fog, but the more sunlight they absorb the more efficient they are. Thin-film solar panels can absorb a broader spectrum of light than traditional solar cells, including visible light, infrared light and some ultraviolet light. On cloudy days most of the direct visible light (sunshine) is blocked, but reflection and diffraction of visible, ultraviolet and infrared radiation still occurs, meaning that some light will still reach the solar panel. Solar panels work more efficiently in lower temperatures as high temperatures cause electrical resistance, which slows down the conversion of solar energy into electricity.