Solar power and hail damage

At the time of writing solar photo-voltaic power was being installed at an enormous and increasing rate around the world, and particularly in my country, Australia.

Solar panels can be damaged by large hail stones and research is indicating that hail storms with hail stones greater than 50 mm in diameter are becoming more frequent, due to climate change, see below.

Any hail storm that will damage solar panels will also damage tiled roofs and motor vehicles (solar panels are being used to protect cars from hail) and could injure people and animals. As mentioned below, two months before the storm that is the main subject of this page another killed 400 kangaroos and 150 goats elsewhere in NSW.

If exceptionally large hail stones are going to become more common they will have implications far beyond solar panels.

This page was written 2018/12/28, last edited 2020/12/14
Contact: David K. Clarke – ©

Destructive hail is likely to increase with climate change

Insurance Australia Group

An article published in Insurance News, 2020/09/09, reported on weather hazard projections relevant to insurers. It gave a summary of weather warnings from a report done by Insurance Australia Group Limited (IAG). I'll quote three paragraphs from the article:
"Insurers have already paid more than $3.85 billion in claims to date for four of these major weather events alone, including the summer bushfires, the South East Queensland hailstorms in November, hailstorms across NSW, ACT and VIC in January, and storms across the east coast in February, according to the Insurance Council of Australia."

"Hailstorms with large to giant hail – from 2 centimetres to above 5 centimetres in diameter - have already increased in frequency over south-east Australia. In a warmer climate, the areas most at risk of these hailstorms will be further south including Sydney, Adelaide, Perth, Canberra and Melbourne."

"Large-sized hail risks will particularly increase in an area from the Hunter River through to the southern NSW Highlands, as well as in parts of Victoria."

The Conversation: "Destructive 2018 hail season a sign of things to come"

Samuel Childs wrote a piece for The Conversation on 2018/09/20 titled "Destructive 2018 hail season a sign of things to come".

Data published on Mr Childs' article showed that hail storms in which there were exceptionally large hail stones were becoming more frequent. The records indicated that both hail stones greater than 50mm and greater than 75mm were becoming more common. Climate science indicated that this was to be expected with climate change and the consequential increasing prevalence of violent storms.

In Australia

On 2018/10/16 the ABC reported that a "Hail storm kills 400 kangaroos and 150 goats on properties in far-west New South Wales".

The implications for solar panels

Hail damage to solar panels in the Sydney December 20th 2018 storms
Hail damage to solar panels
Photo December 2018
I had not originally noticed, but the damage is not random. Four or five of the panels seem not to have been damaged at all while others have been heavily damaged. Is this due to some of the panels being stronger than the others? The three at the right rear could have been protected to some extent by trees, but that could not explain the lack of damage in the one second from the front on the right.
Jenny Noyes reported on 2018/12/25 in the Sydney Morning Herald about the damage inflicted to "almost 3500 homes in the Sydney metropolitan area" from exceptionally damaging hail storms of 2018/12/20. Ms Moyes reported that "Statewide, the number of homes that have required repairs has exceeded 5300, and is expected to grow as calls continue to come in."

At the time of writing it was not possible to get any information on the number of solar panels that were damaged but there was anecdotal evidence for bad damage in at least some isolated areas.

On 2019/01/07 it was reported that almost 60,000 cars had been damaged by the hail storms. Insurance claims numbered over 81,000 and were nearing a total of $675 million.

A Web site providing information on solar power, Energy Sage, had a page titled 'Can solar panels withstand hail and survive hurricanes?' at the time of writing, 2018/12/28. It stated that "In most cases, solar panels are tested and certified to withstand hail of up to 25 mm (one inch) falling at 23 meters per second."

But as reported by Mr Childs (The Conversation, above):

"Here in Colorado, over 20 percent of severe hail reports through the beginning of September have been at least 2 inches [50mm]. Three percent have been at least 3 inches [75mm] – bigger than a standard 2.75-inch baseball. These are the highest such percentages in state history. Moreover, Colorado saw a new record, with hail greater than 3 inches in diameter reported 10 times, over seven different days."
Mr Childs' data showed that in the USA hail stones larger than 50 mm had become more common in the period from 2010 to 2017.

Climate scientists have been warning for years that the intensity of storms will increase as anthropogenic climate change progresses.

Utility scale solar farms

Tailem Bend Solar Farm, under construction 2018/11/26
Tailem Bend solar farm
Photographed by my drone

At the time of writing (December 2018) most new utility scale solar farms were being built with single-axis Sun tracking capability. This would allow the panels to be adjusted to maximum tilt whenever a possibly destructive hail storm was expected, so minimising the likelihood of damage.

Whether the operators of the solar farms are all aware of the need for this, and whether they have put procedures in place to make sure that it happens when it is needed, is another matter.

Implications for roofing



When I was young the great majority of Australian houses were roofed with galvanised corrugated iron. Later it became fashionable to use tiles, either baked clay or concrete; in that period corrugated iron was thought only good enough for sheds. In the last decade or two corrugated iron has again become the way to go for the fashion conscious, probably at least partly because it is now available in a range of colours.

Considering the recent hail damage I suspect that tiles will be even less popular in future.

In the Sydney hail storm of 2018/12/18 where solar panels were on tiled roofs the panels protected the tiles beneath. Where there were no solar panels tiles were commonly broken. I did not hear of corrugated iron roofs (which are common in Australia) being damaged.

Skylights were also damaged.

Where solar panels protected the tiles beneath there would have been less damage due to leaking roofs than in those houses with tiles and no panels.

It would be interesting to know the comparative cost of repairing the houses – roofs, panels and water damage – with and without solar panels. In late 2018 solar panels were probably comparable in cost to a similar area of roofing tiles.

Using solar PV panels to protect cars from hail

Solar panels being used to protect cars from hail
Car protection
The photo is of a car dealership in McKinney, Texas, USA.

Image credit Autonews, Canada
The photo on the right was in an articles titled "How solar panels can protect dealerships in Canada's Hailstorm Alley" written by Kelly Taylor in Autonews, Canada.

Kelly Taylor wrote:

"In 2015 at his three dealerships in the heart of Alberta’s Hailstorm Alley, Garrett Scott felt Mother Nature’s wrath: 600 vehicles damaged with an average claim of $11,000."
The car dealer was covered by insurance, but still suffered substantial financial losses, and of course, the insurance company would be advantaged by having their risk at this business greatly reduced in future.

Hail damage to panels – possible.
Hail damage to cars – avoided

In the context of this page it is interesting that the possible financial risk from future hail damage to the solar panels must be considered to be small in comparison to future hail damage that will be avoided on the cars.

A win-win-win situation

The car dealers involved would gain by reducing their power bills as well as protecting their cars from hail damage. The planet gains by increased renewable energy abating fossil fuel generated energy.