Risø DTU demonstrates polymer solar cells at the Roskilde Festival

A year ago a group of scientists from Risø DTU, headed by senior scientist Frederik Krebs, decided to demonstrate that polymer solar cells have a great potential: Plastic is a cheap material, the cells can be mass-produced and used in a more flexible way than silicon solar cells. But the key value of polymer solar cells is that – potentially – they can be produced in high quantities considerably cheaper than other solar cells.

The deadline for cells and hats Sunday 29 June 2008 was met. At 10 o’clock innovation pilot Torben Damgaard Nielsen and 3 PhD students from Risø DTU were standing in the climate stand, Rock the Climate, at the Roskilde Festival. At the stand you can see a solar cell panel made of silicon, take part in building a house with festival garbage and get to know what the festival is doing in order to be more eco-friendly and also learn what you yourself can do.

The Risø DTU scientists have brought with them 1,000 round polymer solar cells, 13 cm in diameter. Some of them are sewn into brilliantly coloured sunhats and connected to a small rechargeable battery powering a small radio. Others are placed in a plastic panel on a parasol supplying power for an electric racing track. And others can be touched by the guests and connected to calculators and watches. In this way the guests can see for themselves: The solar cells are working.

The fact that the sun is shining does not harm the story; but actually the Roskilde Festival solar cells do have sufficient capacity for a calculator, also when placed in the shadow. The battery in the radio is charged by the solar cell, so the radio is able to play even when you step inside a tent.

The group of scientists admit that it has been hard work with a lot of hindrances. But the joy of having carried on is tremendous.

”As far as we know no one else in the world has done the same – distributed polymer solar cells in public as we are doing here,” says Frederik Krebs. ”To me it has been really important to show that we could produce the cells in existing industrial plants to be ready at a certain time. My philosophy is not only to talk to other specialists about what I am doing; I also want to show that it can be put into practice.”

The Roskilde Festival was an obvious occasion to do so.



See more pictures from the Festival

Facts about Risø DTU’s polymer solar cells
Risø’s research into solar cells is leading when it comes to stability and manufacturing process. The massproduced cells are able to tolerate more than 1000 hours of direct sun, while Risø DTU laboratory results show 8.000-10.000 hours under accelerated conditions.

The energy efficiency is lower than for the silicon solar cells which transform 15-20 % of the sun’s energy into power; right now the efficiency of the Risø DTU polymer solar cells is around 2.7 %. It is expected to rise to 5-6 %. The fact that the polymer solar cells are considerably cheaper and easier to produce compensates for the lower energy efficiency.

If you reach a process speed of 1-2 square metres polymer solar cells per second, you should be able to produce just as many square metres of polymer solar cells per hour as a traditional solar cell factory is making in one year.

Collaboration with the Danish industry
Even within the next year or so the group of scientists expect to be able to demonstrate that it is possible to produce a large area of polymer solar cells quickly and cheaply. The scientists are cooperating with a Danish printing company, where the polymer solar cells for the Roskilde Festival was produced by screen printing.
”Research into polymer solar cells is a strategic research area where we interact with the outside world – in this case with Danish companies. Already in the research phase the cooperation gives the companies a good foundation for making polymer solar cells a good bargain,” says head of programme Peter Sommer-Larsen.

Risø DTU has been conducting research in materials and polymers for several years. That is why we have good resources and the right equipment for doing research in polymer solar cells.