Martin Green is Scientia Professor at the University of New South Wales, Sydney and Director of the Australian Centre for Advanced Photovoltaics, involving several other Australian Universities and research groups. His group’s contributions to photovoltaics are well known and include inventing the PERC cell, now the main commercial cell, and holding the record for silicon solar cell efficiency for 30 of the last 36 years, described as one of the “Top Ten” Milestones in solar photovoltaics history. Major international awards include the 1999 Australia Prize, the 2002 Right Livelihood Award, also known as the Alternative Nobel Prize, and most recently, the 2018 Global Energy Prize presented in Moscow last October.
Can we get to 50-year PV module life by reducing operating temperatures?
Under bright sunshine, photovoltaic modules typically operate 30oC above ambient in the field when rack-mounted and 10-15oC additionally hotter when roof-mounted. This reduces peak output by 15-20% and accelerates all chemical degradation processes within the module, with present service life typically 25-30 years. Since each 5-10oC temperature rise doubles the rate of common module degradation processes, reducing operating temperature by this amount could extend module life by 50-100% in some applications, putting 50-year service life within reach. Passive approaches are outlined for attaining this cooling by decreasing parasitic infrared energy absorption as well as by increasing cell efficiency and heat dissipation by radiation, convection and by conduction to module frames and supports. Combining the most promising approaches, nominal module operating temperature (NMOT) below 40oC as a near-term target appears feasible.