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Hailstorms in the US and Australia have severely damaged solar panels – including golf ball-sized hail at the 350MW Fighting Jays project in Texas in March 2024 – causing insurers to hike premiums and reduce or cancel hail cover. Simon Mason, partner at energy consultancy Everoze, looks at the challenges facing the sector to minimise its exposure to hail risk.
Modules are the main point of failure for solar projects during hailstorms. Wafer sizes have increased from M6 (166 x 166 mm) to M10 (182 x 182 mm) and G12 (210 x 210 mm), and panel dimensions have gone from 1 meter by 2 meters to 1.3 meters by 2.3 meters and even more. Thinner frames and glass have helped lower prices, but they have also reduced product strength.
Recent Australian solar projects have used bifacial panels with 2mm thick front and rear glass. They are typically certified to the International Electrotechnical Commission (IEC) minimum test standards for 25mm ice balls, and typically pass 35mm hail impact tests. Severe Australian hailstorms have always had hailstones larger than 35mm, and climate change is making these events more frequent and more damaging.
Some labs have introduced more stringent, customised tests that go beyond the IEC minimum requirements. As a result, some manufacturers are offering customised BOMs with 2.5mm front and rear glass. This increase in glass thickness comes at a weight penalty, but in many cases the modules can pass a 45mm hail impact test.
Manufacturers have also launched “hail-resistant” modules with 3.2mm front glass and 2mm or 1.6mm rear glass that can withstand 50mm and in some cases 55mm hail impact tests. These modules are heavier and in a market such as Australia where health and safety limits on manual handling make the use of panels weighing more than 40kg prohibitive, the size (and power class) of such panels that can be used will be limited.
Selection of shelves
In areas where severe hail storms occur, for projects using trackers, having a hail restraint mechanism can significantly reduce the number of panels damaged during such weather conditions. By tilting the panels away from the direction of the hail, the angle of impact can be increased and the energy of the hail can be reduced. Most major tracker manufacturers now offer a hail restraint feature on their products and this feature should be included in the employers requirements for new projects.
Fixed-tilt projects cannot rely on a smart stacking strategy. Regardless of the racking system used, the additional weight of the modules must also be taken into account during structural design to ensure adequate strength and rigidity.
A 2023 study by the University of Queensland and the Australian Bureau of Meteorology identified the south-east corner of Queensland and the north coast of New South Wales as Australia’s most hail-prone areas. These areas include the Central West Orana and New England Renewable Energy Zones (REZs) under development in New South Wales, as well as the Southern Downs, Western Downs and Darling Downs REZs in Queensland. The Australian Energy Market Operator’s draft integrated system plan for 2024 projects these areas to host up to 14 GW of new solar by 2040.
Similar studies conducted in other regions illustrate the importance of taking into account hail risk and, more generally, environmental risk at an early stage of project development. Knowing the expected climatic risks will allow developers to choose the best equipment for a site, reducing risk and ensuring the long-term bankability of portfolios.
At the procurement stage, it is important that hail impact testing is carried out by independent, accredited testing and certification authorities and that this is included in the contractors requirements for new projects. In general, a successful procurement should include a factory audit and a range of tests that go beyond IEC standards, both before shipment and on receipt on site.
Insurance Issues
For a developer, the most efficient way is to have as much generation capacity as possible in the same geographic area. Everyone likes to have a “second phase” or even a “third phase” of a project expansion, but for an insurer, such geographic concentration increases the risk of a major loss.
Aside from the technical mitigation measures mentioned above, developers may seek to purchase insurance at the portfolio level rather than at the project level, to take advantage of portfolio scale and geographic diversity. This may be a way to increase the coverage available for projects in hail-prone regions at a manageable cost. Developers who spread their projects across multiple locations will be able to avoid concentration risk and may be able to pursue a portfolio-level insurance strategy.
Future planning
Anticipating the impact of a hailstorm is no easy task. Developers need to carefully consider the location of projects in the broader context of their portfolio and ensure that design and procurement decisions are made with due consideration to hail risk and the mitigation strategies discussed above. Ensuring the durability of PV projects requires a range of expertise including planning and defining an insurance strategy, as well as proper design, engineering and procurement. With the help of a thorough climate risk assessment that assesses and mitigates the commercial and financial impact on operating expenses, revenues or project life from the early stages of development, this should ultimately help keep future lenders’ requirements manageable.
About the author: Simon Mason is a partner at Everoze, a technical and commercial energy consultancy specialising in renewables, energy storage and flexibility. He is one of the founding partners of Everoze in Australia and has been working on large-scale solar, battery energy storage and wind energy projects in Australia and South East Asia since 2008. |
