In 2030, solar energy will be the least expensive form of all, predicts Prof. Miro Zeman of Photovoltaic materials and Devices in the Faculty of Electrical Engineering, Mathematics and Computer Science.

“What we see as light is electro-magnetic radiation between 380 and 780 nanometres. However, solar radiation comprises much more than that. Our solar cells can also transform the invisible radiation into electricity. For example, silicon solar cells are sensitive to infrared radiation up to 1200 nanometres. Germanium goes even further, to 1900 nanometres. We are investigating ways of transforming as much of the solar spectrum into electricity as possible. One good example involves the expensive solar cells with which the first Nuna solar cars were equipped. They consisted of three stacked solar cells of different materials, each of which was sensitive to a different part of the spectrum. This allowed them to achieve an efficiency of 35%. Silicon solar cells achieve up to 25%. We have just submitted a publication on a new type of thin-film solar cell with four different silicon-based materials, with which we have established a new efficiency record. I think that such multi-junction solar cells will be able to achieve an efficiency of over 50% within a few years. Just compare this to a coal-fired power station that produces electricity with an efficiency of 30%–40%. In 2030, an efficiency of 40% will be quite normal for solar panels.

The production volume of solar cells has grown immensely. In China, there are factories that produce PV panels for 5 gigawatts per year. There is also no shortage of silicon. The price of solar energy will therefore continue to decline. In 2030, solar energy will be the least expensive form of all. In Germany, this is already the case in some instances. Companies are shutting down coal-fired power stations, because they cannot compete.

The challenge for 2030 will be to determine how we can fit inexpensive solar energy into the existing electrical facilities. In addition to PV cells and transformers, this will require research and investments in the storage of electrical energy.

Although the research being conducted in our department is at the highest international level, no industries in the Netherlands are currently making use of this knowledge. If a company with new technology for solar panels wanted to build a factory, they might achieve 5–10 megawatts per year for a niche market. One Chinese factory is producing a thousand times more than this. It would be impossible to set a price that could compete with that. We like to collaborate with Hyet in Arnhem, which would like to produce flexible thin-film solar cells for applications in the built environment. In the future, however, I think that we will also have to talk with people from Japan and China. At the end of the day you do want your research results to be applied”.

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