The value of stability in photovoltaics

Warranties for photovoltaic modules last 25 years. The same duration is frequently used when predicting economic performance. Yet, many modules still produce more than 80% of their original power after 25 years, and there is no economic reason to retire them. Here, we adopt a different mindset: photovoltaic installations are operated indefinitely with maintenance at regular intervals. We reflect this view in a steady-state economic model. We find that in this view, maintenance gains in value -33% compared with a 30-year lifetime-and time constraints for maintenance are lifted. We also find that stability becomes even more important. Reducing annual degradation from 0.5% to 0.2% entails a 12 ct/Watt cost entitlement, increases the economically useful lifetime by a factor of 1.69, defers end of life by decades, and reduces resources and infrastructure needed for recycling by 40%. We foresee that modules installed today should ideally be operated for 50 years.