An anonymous reader writes: SolarCity released a new report that says solar power systems have a usable lifetime of at least 35 years, which is 40% longer than what the market expects. Electrek reports: "The key finding of the report is that power degradation (annual efficiency loss) of solar panels supplied to SolarCity is as much as 35% lower than for a comparable industry-wide selection of non-SolarCity panels, which are typically expected to last for 25 years. In the study here, SolarCity looked at greater than 11,000 panels to determine their data points and come to their conclusion that their solar panels are performing well beyond expected industry standards. Today, standard efficiency solar panels put out by Tier 1 suppliers are generally warranted to lose no more than 0.7% efficiency per year for the first 25 years -- this is the Power Production Warranty. The key finding in this study is that the annual 0.7% efficiency loss is too high an estimation -- and that the number ought be closer to 0.5%. While it might seem a small number -- a difference of 0.2% -- when applied over a multiple decades timeframe, it means that instead of the standard twenty five year assumed productive life, we can expect at least another ten years of production above 80% of the original system output. Large installers like SolarCity, able to do this type of wide-scale research -- and to also demand higher quality, are showing their ability to pull the manufacturers of the world upward. With SolarCity building their own solar panel Gigafactory we ought expect the quality levels to be even greater in the near future.