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Energy payback time of crystalline silicon solar modules

1997; Springer Nature; Volume: 11; Linguagem: Inglês

0731-8618

Johan Nijs, Robert Mertens, R. Van Overstraeten,

Silicon and Solar Cell Technologies

The energy pay-back time of crystalline silicon PV-modules varies from 2.58 (multi c-Si) and 2.66 (mono c-Si) years for the sunbelt region to 4.92 (multi c-Si) and 5.07 (mono c-Si) years for continental climate, high latitude regions in the state-of-the-art production technology. It varies from 1.40 (sunbelt) to 2.67 (continental climate, high latitude) years for a medium term projected scenario based on thinner wafers and better material yields, higher efficiencies and frameless modules. In the long term for efficiencies of 20%, pay-back times are reduced to 1.22 and 2.33 years for the corresponding regions. Pay-back times obtained in this study are rather conservative because the kWh-content of semiconductor grade silicon is accounted for in full. A sensitivity analysis shows that a reduction of the kWh-content of semiconductor grade Si with nearly 50%, results in a 30-40% reduction in pay-back times in all scenarios: for the actual scenario, energy payback time would go down to 1.63 (multi c-Si) or 1.74 (mono c-Si) years for the sunbelt region and 3.12 (multi c-Si) or 3.33 (mono c-Si) years for continental climate, high latitude regions. For the medium term projection, these figures would even go down further to about 0.9 years for the sunbeltmore » region and about 1.7 years for continental climate, high latitude regions. Considering semiconductor grade as waste material from the electronic industry (as is currently utilized) with no accountable kWh-content even reduces the pay-back times by 70-85%: for the actual scenario, the energy payback time would decrease to 0.51 (multi c-Si) or 0.65 (mono c-Si) years for continential climate, high latitude regions. For the medium term these figures would decrease further to around 0.3 years (4 months) for the sunbelt region and around 0.5-0.6 years (6-7 months) for continental climate, high latitude regions. 25 refs., 8 figs., 13 tabs.« less