The photovoltaic market of 750 MW/year is dominated by Si wafers and grows with an annual rate of around 30%. At the beginning of 2004, about 350 MW of photovoltaic power is installed in Germany. Based on an annual growth of 20 to 30%, between 8 and 30 GW will be installed in 2020. The production cost of the crystalline Si modules halve about every ten years. At present, solar electricity costs 0.6 EURO/kWh in Germany. Provided the mass production continues, this number may drop to about 0.2 EURO/kWh in 2020. Classic materials of so-called second generation photovoltaics such as amorphous Si, CdTe, Cu(In,Ga)Se-2 have either physical, ecological or technological disadvantages. Only crystalline Si itself, in thinner form (either as thinner wafers or as a thin film) will probably be able to add to or to replace the technology of about 200 to 300 pm thick Si wafers. New physical concepts in photovoltaics, so-called third generation photovoltaics, could lead to photovoltaic conversion efficiencies of above 30%. However, also in this case, concepts that make use of crystalline silicon seem to be the most promising.
