Swiss start-up VHF solves Q-Cells’ silicon shortage problem

Flexcell flexible solar panel on a corrugated roof.

VHF will use the €8 million investment to boost its production of Flexcell solar panels from 1,000 square metres a year to 40,000 square metres, or 2 megawatts.

The company, a spin-off from the Institute of Microtechnology at the University of Neuchâtel, uses amorphous silicon extracted from silane gas. Its process for producing thin plastic films with amorphous silicon was developed at the institute in the late 1990s by Arvind Shah and Diego Fischer.

Amorphous silicon is cheap and abundant, although it is a markedly less efficient producer of solar energy than monocrystalline silicon, the basic material of traditional photovoltaic cells. The efficiency rate of Flexcell is limited to a maximum of 5 per cent in commercial panels, while it can reach up to 12 per cent with monocrystalline silicon cells.

But purified monocrystalline silicon is in short supply, with photovoltaic manufacturers having to compete with the semiconductor industry for their raw material. Prices have soared from $50 per kilogram to $150 per kilogram, slowing the photovoltaics market.

Worldwide, the market is expected to grow from $11.2 billion in 2005 to $50 billion by 2015. But this year, owing to the silicon shortage, growth will be only 10 per cent.

Apart from cost and availability, Flexcell’s flexibility offers a number of advantages. According to the manager of VHF, Alexandre Closset, “instead of a batch process to encapsulate the silicon cells between glass panels, our plastic films roll into the process. It increases dramatically the productivity.” The cost of a watt (peak) is around €3 for today’s VHF cells. But with mass production Q-Cells and VHF hope to reduce the cost to €1.

With Swiss roof maker Eternit, VHF has already embedded its flexible cells into new roof parts. “We are currently looking for partners to further integrate our plastic cells,” says Closset. The company, which keeps close links with its alma mater in Neuchâtel, is also taking part in a European research project, Flexcellence, to raise the efficiency of amorphous silicon to 10 per cent.  

There are an estimated 23 billion square metres of roofs in Europe and the US. This surface, covered with solar cells, would translate, says the International Energy Agency, even at only 5 per cent efficiency, into an electricity output of 1,000 gigawatts.