Because the current shortage of solar-grade crystalline silicon wafers is expected to continue until 2011, Taiwan- and China-based makers have demanded a 5-15% pre-payment for supplies beginning 2011 depending on supply volume and contract period, according to industry sources.

While Taiwan- and China-based wafer makers have been expanding their capacities, the increase is still unable to meet the fast growing demand because of a shortage of wafer-making equipment, the sources pointed out.

Pre-payments are 10-15% of contract value for one-year contracts, and 5% for 3-year contracts, the sources indicated. Alternatively, the percentage pre-payment is based on the total supply volume of a contract, the sources added. Viewing that global PV market conditions are likely to fluctuate, contract prices will be adjusted based on price or related indicators regularly published by PV surveys or research organizations, the sources noted.

The wafer capacities of Taiwan- and China-based makers are already almost fully booked for 2011, the sources pointed out.