In this week’s PISA episode, host Olivier Catani speaks to some of the scientists working on these projects.
Our previous episodes covered the history of the tram, Luxembourg airport, explained how the coronavirus vaccine works, asked why traffic lights always seem to be red, investigated where our tap water comes from, looked at Luxembourg’s railways since 1859, took a dive into the Moselle Valley and its underground Dolomite mines and the history of Radio Luxembourg...
Solar cells are becoming smaller, more efficient and starting to blend in better with their environments.
Guy Spaus lives in Noertzange and shows the video team his new roof with integrated solar cells. “They’re well hidden, aren’t they? It looks like a normal roof,” says Guy. The problem is no provider wanted to install the standard “boxy” solar panels on his Eternit roof for safety reasons. Alternatively, they adopted this integrated system, which is not only efficient but also aesthetically convincing.
These types of photovoltaic installations are supposed to generate most of Luxembourg’s electricity demands in the future. Beidweiler, in the commune of Junglinster, is currently home to the largest solar park of Luxembourg, covering its grassy meadows besides the RTL antennas.
8 gigawatt hours are generated by this solar panel park alone, enough to provide 9,000 people (or roughly 2,000) families per year with solar electricity. Luxembourg wants to boost capacities and is even looking into installing panels on land currently used for agriculture (yes, that could mean between corn and cows).
At the University of Luxembourg, a team of scientists is currently researching the energy production of coloured solar cells to see to what extent they can seamlessly be integrated into the facades of buildings without losing too much power - a delicate balance.
“The challenge of coloured solar cells is to get enough light into the solar cells so it can still work, but still get some of the light into your eye so you can still see a nice colour,” explains solar researcher Philip Dale.
Dark cells absorb all light and reflect none, hence solar cells have so far mostly been dark. “Our dream in the future is to create pixels so we may make images or photographs or camouflage the solar modules,” says Dale.
Another project is creating transparent solar cells that could even be fitted on windows. This remains highly challenging but could revolutionise our green electricity production.
Professor Siebentritt and her team make use of a vapour deposition machine to create super thin absorber films made of copper and other materials that then generate electricity.
“It’s basically like a cooking pot, we heat the elements in vacuum environments at very low pressure. They vaporise and deposit on a glass panel, or even a metal foil, in the centre. That’s how we form our semiconductor films”. The university is now looking into what layer combinations of different materials yield the best results.
Colleague Alex Redinger adds: “If one layer is too thick or has the wrong properties, the entire system won’t work”. On top of that, the result must be both energy and cost efficient.
The country’s first floating solar panel park was opened in collaboration between ArcelorMittal and Enovos-Enveco.
An area the size of eight football fields was connected to the national grid one year ago, generating three gigawatt hours of electricity per year, covering 800 households.
But what happens when there is no sunshine? A smart grid is needed whereby electricity is always stored for times when no constant supply is guaranteed.
Researchers are working on systems that can regulate electricity output based on expected weather conditions. AI is then deployed to correct any potential errors.
“Imagine a tree casting a shadow on a solar panel every morning between 8am and 10am,” explains Daniel Koster from the Luxembourg Institute of Science and Technology (LIST). “Algorithms can learn from these discrepancies”.
Smart meters even capture images of the sky. “We can also deduce insights about cloud thickness and in turn their shading effects,” adds Koster. This valuable data then allows electricity providers to plan accordingly.
