A Winter’s Tale

Steve Pester, BRE, examines how lessons learned from the wettest winter on record can be applied to the production of solar panels

Having toured the West Country on business twice in the last month, I have had first-hand experience of some of the effects of the recent extreme weather events. Specifically the £200 bill to have my car electrics dried out and repaired after testing my Renault’s amphibious capabilities is testament that your average car is not yet really equipped for climate change.

At the National Solar Centre, we’ve been wondering if solar panels will fare any better. What effect will all this rough weather have on the efficiency and longevity of the current generation of solar modules? These days modules are robustly sealed and tested for water ingress under the IEC 61215 / 61646 tests, but what about possible mechanical damage due to the shaking and vibration in turbulent winds typically seen around buildings?

In a bid to continue the trend of reducing module costs, manufacturers are always trying to make use of thinner silicon cells, thereby using less of the expensive stuff. In 2004 silicon wafers (from which the cells are made) were typically around 300µm thick; these days 150 – 200µm is more typical. An obvious possible consequence of this is that they are more prone to mechanical damage – in fact the main reason for not making them any thinner than this is that they become hard to handle in the factory without breakages.

So, one of the things the NSC will be looking at, on our windy outdoor test site in Cornwall, is micro-cracking of cells in real conditions. Microscopic cracks in the silicon reduce the efficiency of cells and could even become a serious degradation factor over the long term but without hard evidence this is all conjecture, of course. The main purpose of the NSC is to obtain real-world, trustworthy data for the solar industry.

Unfortunately, we don’t yet have the facilities to test the underwater capabilities of cars… perhaps on Top Gear.