Solar cell technology has been constantly upgraded over the past several years, where conversion efficiency has been rising each year, though the corresponding cost has also dropped expeditiously. Will this affect the durability of solar panels? According to the 5-year test conducted by the laboratories under US Department of Energy, the new model of solar panels is estimated to retain 80% of initial power generation after 30 years of use.
The Sandia National Laboratories (SNL) unfolded a 5-year research on the degradation of solar modules, where 23 different solar systems from 7 suppliers are purchased under three climate conditions, and 834 installed solar panels were tested for their performance at the end.
Recent years saw significant changes to the type of solar cells. The traditional Al-BSF design was the mainstream variation on the market during 2018 at a sizable ratio of 90%, and the market had steadily shifted its attention to cell designs such as PERL, PERT, SHJ, and TOPCon after 2020. As pointed out by the report, these new solar cells and modules lack long-term field data.
Due to automated production under economies of scale, the cost of solar modules adopted with newer cell designs that come with a higher efficiency had dropped 85% over the past decade. Marios Theristis, leader of the team, pointed out that a lack of long-term field data for new technology will deter from providing answers to the doubts that people have on the durability of solar panels under the swift changes of the solar market, which is why the team decided to make direct purchase and implement analyses on retail solar panels, before announcing the relevant date anonymously. The team also worked with the National Renewable Energy Laboratory (NREL) and University of Central Florida (UCF) on installing the same systems under different climate conditions.
The team unfolded the experiment in New Mexico, Colorado, and Florida. Performance and initial power stability of solar panels were tested under standard conditions during the beginning of the experiment, before regular tests on monitoring the status of degradation were executed throughout the five subsequent years.
The team discovered that the degradation rate was highly nonlinear at roughly -0.6% each year, which was similar to modules in the past, despite having manifested seasonal changes. Among the 23 different solar systems, 6 of them had exceeded the warranty limit in degradation rate, while 13 of them had rendered a potential lifespan of more than 30 years (assuming that degradation is stable).
In the face of changing solar cell technology and plummeting cost as solar panels elevate in installations, consumers and stakeholders are bound to be interested in knowing if solar panels are consistent in durability, for which Theristis believes that the results were quite remarkable, though he also pointed out that 26% of solar systems would exceed the limit of warranty, and that the degradation rate must be brought down in order to prolong the lifespan of solar panels.
Comprehensively speaking, the degradation rate of solar modules did not seem to have been affected by the rapid drop of cost over the past decade.
(Cover photo source: SNL)