Installing solar panels. (Image courtesy of MIT.)
The value proposition that solar panels present to homeowners and businesses who pay for power is simple. The significant up-front costs associated with buying the panels themselves and installing them as a system will eventually be paid for by the panels as they generate â€śfreeâ€ť energy over their lifetimes. That high-leverage model only makes economic sense if the value of the power generated by the solar panels over their useful lifetimes exceeds their initial cost. A key question in the solar industry, then, is simple: How long should a panel be expected to last in order for it to be worthwhile?
The answer may be much lower than the conventional wisdom suggests. A new paper published recently in the journal Joule describes a paradigm shift taking place in the solar market. Authors Joel Jean, Vladimir Bulovic and Michael Woodhouse say that technological advances and market forces have combined to render obsolete the notion that solar panels must last for at least 25 years to be worthwhile. If the broader solar industry accepts this idea, it could open the door for advanced solar technologies that have been shelved due to concerns about their longevity.
Central to the researchersâ€™ claim is that the cost of solar panels has plummeted in recent years. Simultaneously, their efficiency has skyrocketedâ€”and can be expected to continue this trajectory for years to come, according to the researchers. These changes are such that the cost of land, installation, maintenance, racking, permitting and other factors now exceeds the cost of the panels themselves. â€śMost of the technology is in the panel, but most of the cost is in the system,â€ť Jean said. â€śInstead of having a system where you install it and then replace everything after 30 years, what if you replace the panels earlier and leave everything else the same?â€ť
To prove that this concept might work, the study looked at three types of solar projects: a small residential installation, a large commercial facility, and a utility-level 100-megawatt behemoth. They ran simulations on each project using todayâ€™s market values to arrive at an initial cost. They then plugged in various assumptions about the efficiency of panels at different points in the future to calculate the levelized cost of electricity (LCOE) against conventional power sources. In every case, the scientists determined that panel replacement after 10-15 years could still yield cost advantages while retaining the environmental qualities that make solar so important.
The paperâ€™s authors agree that many promising solar developments have been tabled because of the dogmatic presumption that a panel that couldnâ€™t last 25 years would never catch on. They point out that todayâ€™s solar panels werenâ€™t rated for 25 years of use in their infancy, either, and only significant refinement raised them to the standards enjoyed today. Widespread awareness of these findings could broaden the range of solar innovations considered promising enough to warrant further investment. An acceptance of shorter lifespans by the broader market could be crucial to solar powerâ€™s development. The faster nascent technologies are able to get to market for testing at scale, the better for the race to curb emissions.