The solar panel paradox:useful for the climate but fragile in the face of extreme events

The hailstorms of recent days have damaged hundreds of photovoltaic systems.And now the experts warn:«We need to start studying more resistant modules»

What happens when one of the best allies against climate change is threatened by the very thing it is supposed to fight?The hailstorms which hit Northern Italy in recent days have damaged not only trees, cars and homes but also many photovoltaic systems.There are no official estimates yet, but both in Emilia-Romagna and Lombardy there are reports of solar panels ruined - or in some cases completely destroyed - by hail.At the end of 2022, according to data from Italia Solare, there were over 1.2 million photovoltaic systems active in Italy, for a total power of more than 25 GW.What is now worrying producers and consumers is the increasingly high frequency of extreme meteorological events, one of the most evident effects of climate change.«Something should be changed – admits Sonia Leva, professor of the Energy department at the Polytechnic of Milan -.Climatic conditions are changing very rapidly and this requires us to study different ways of designing photovoltaic modules."

Anti-hail tests

Solar panels are made up of several layers.The outermost one - and most subject to weather conditions - is tempered glass which has a thickness between 3 and 4 millimetres.Under the glass there are then two sheets of plastic material - which contain the photovoltaic cells - and the so-called backsheet, i.e. the back part of the panel.To date, Italian legislation requires photovoltaic modules to be subjected to an anti-hail test, in which the panels are hit with spheres with a diameter of approximately 25mm launched at speeds of up to 80 km/h.«Until ten years ago I would have said that the legislation was far too severe, but after the events of recent days I take it all back», comments Leva, who in addition to being an expert in the sector has experienced firsthand the damage of the hailstorm that hit Milan.«My panels were completely destroyed – he says -.We had ice spheres bigger than a tennis ball.Dimensions well above any anti-hail test."

According to the Polytechnic professor, the increasingly high frequency of extreme weather events could push manufacturers to study solar panels that are more resistant than the current ones.A process that currently faces two problems:efficiency and weight.«A thicker glass can certainly help against strong hailstorms but it allows less light to filter through, reducing the efficiency of the photovoltaic module», explains Leva.The other unknown is represented by the weight of the panels.«Increasing the weight of the modules means that the roof structure will have to support more weight.I believe that in the end we will have to find the right one trade-off between greater resistance and performance of the modules".Alessandro Villa, CEO of Elmec Solar, also shares the same idea:«Each millimeter of glass thickness corresponds to an increase in weight of approximately 2.5kg per square meter and consequently requires a general redesign of the supports.All aspects that will have to be studied, tested and then certified."

Insurance and disposal

Andrea Brumgnach, vice-president of the Italia Solare association, also confirmed the damage caused by the hailstorms of recent days:«We have had several reports on both small and larger plants, in particular from Brianza».Whether it be companies or private homes, the only way to defend photovoltaic systems from events of this kind are insurance policies.«Almost all systems, including residential ones, have insurance.This is because the home is generally covered by an insurance policy.And when you build a photovoltaic system you ask the company to extend the coverage", clarifies the vice president of Italia Solare.In short, for many businesses and families the problem is not so much the economic damage to be sustained in the event of damage to the panels.Rather, it is the cost of insurance.«Insurance companies increase the cost of policies depending on the frequency of these events.What risks happening is a constant upward adjustment of costs", warns Brumgnach.It is also true, however, that solar panels can help avoid damage to the structure of the house:«In most cases, during bad weather, the system protects the underlying roof, preventing it from breaking and flooding the rooms below», underlines Villa, of Elmec Solar.

Anyone who has suffered damage to their photovoltaic system finds themselves facing another issue:the disposal of the panels.Also in this case, there is no additional cost for the owner to bear.For systems up to 20 kW it is expected that in the initial construction cost you will also pay a fee dedicated to the disposal of the modules.Once damaged, the solar panels are taken to a special center for disposal.«To date we are able to dispose of around 80% of the weight of the module, i.e. the glass, the copper cables and the frame – explains Sonia Leva -.What we are still working on are the photovoltaic cells and the plastic film, which maintain the most valuable materials."The first real wave of photovoltaics in Italy occurred around 2010.Estimating an average life of 25-30 years, it is expected that around 2035 the treatment plants will see their activity increase significantly.For this reason, some projects are underway, many of which are encouraged by European funds, to improve recycling techniques.A result that, thanks to the increasingly frequent hailstorms, we may have to achieve even sooner than expected.