The Impact of Flooding and Storms on Ground-Mounted and Rooftop Solar Installations

The use of renewables is vital in the fight against climate change. Renewable energy sources are gaining in popularity and will become part of our everyday lives over the coming years as the different technologies improve. If you look at rooftop solar installations alone, there were 189,000 solar systems mounted on UK rooftops in 2023 registered by the Microgeneration Certification Scheme (MCS). This was an almost 30% increase on 2022 solar installations.

Although solar panels are durable, they can be damaged in severe weather or accidents. The risks associated with the use of renewables are often not considered which poses serious problems for insurers. Having said that solar panels should come with manufacturer and installer warranties that will protect your investment from reasonable weather damage.

Most residential and small commercial solar energy systems are rooftop installations which are less likely to be affected by flood damage. If flooding doesn’t reach the roof of your home, you should have nothing to worry about as long as your home wiring systems are still intact such as the wiring for the solar panel system’s inverter. 

It's a sad irony that solar farms that are meant to help mitigate the effects of climate change can fall victim to the same severe weather conditions that they were created to diminish. 

Extreme weather events are increasing in number across the globe, and this can have a profound effect on solar farms. 

In November 2021, storm Arwen left a solar farm near Wolviston in ruins. Hundreds of glass solar panels at Low Burntoft Farm were destroyed when storm Arwen tore through Teeside. 

A few days ago, a seasonal weather system known in Spain as the “cold drop” or DANA (an acronym of depresión aislada en niveles altos: isolated depression at high levels) caused significant flooding of both rooftop and utility-scale PV systems in the Valencian Community and Castilla-La Mancha in Spain.

The storm left hundreds dead and wreaked havoc in the affected areas. 50 years ago, a DANA occurred every three or four years, usually in November. However today, with the effects of global warming they can happen all year round. 

Flooding can have several effects on ground-mounted solar panels. Panels can be torn from the ground or their racking in severe flooding as was seen in Spain recently. If solar panel systems are exposed to water, there can be serious consequences for electrical devices such as inverters and batteries. It can cause short circuits as water acts as a conductor that bridges circuits. Even once the solar panels are dried out, water residues can lead to corrosion in sensitive electronic components. Water damage can compromise electrical protections which can create safety risks. 

Contact with water and abrasion caused by debris can also damage the insulation of cables and other components. If this damage occurs it can reduce the performance of the system or even result in complete failure. 

In addition, water can erode the soil around a structure’s anchoring piles which will reduce their grip on the ground. 

If the weather conditions are extreme, solar panels can work as lifting surfaces putting the panels in danger of being blown away. It’s extremely important that solar panels are as securely tethered as possible. Solar panels can also be damaged by falling debris carried by the wind. Significant damage to modules, cables, and electrical equipment can be caused If a solar farm is struck by lightning which can end up costing thousands of pounds to repair or replace. 

Strong wind forces can cause micro-cracking or fractures in solar panels. The silicon layer used in a solar panel is very thin making it prone to cracking when it expands and contracts or when it’s damaged by wind or falling debris. If a panel is cracked it will be less efficient at absorbing light and storing energy. If dust and water get into these cracks it can further harm the effectiveness of the panels. 

One reason solar panels don’t always last as long as they should is weather damage and issues with materials and construction. Solar panel installations have the potential to last as long as 40-50 years, but they are currently only usually lasting 20 years. Unless these issues are addressed it will be difficult for solar farms to reach their energy-producing potential. 

However, if your solar panels do become submerged and damaged during an extreme weather event it doesn’t necessarily mean that your panels will be permanently damaged. Many high-quality solar panels can come out of high floods without suffering any water damage due to the solar panel’s design which incorporates an aluminium frame, glass casing, and vacuum-sealed back panel. Of course, if you experience an extreme flood your solar panel system may not operate normally as your home’s panel and inverter wiring may be waterlogged or otherwise damaged. 

What to do if your solar system has been submerged in flooding

Stay away from your solar system
Don’t go near your solar system or the area around it until a qualified electrician has made sure it is safe to do so. 

Check your electricity meter
Keep away from your electricity meter if it is under water and contact your electricity supplier. 

Check your fuse box
Check the fuse box or consumer unit for water damage, overheating, or arcing. Call an electrician if the water level is above the consumer unit before using any electricity. 

Don't turn on your solar system
Don’t try and turn on the solar system or any other electrical appliances. Both solar electric systems and your general home wiring contain high voltages of electricity. You should employ an electrician to ensure your home is safe following any water damage. They will also be able to determine the extent of the damage. 

Check your internal wiring
Employ a qualified electrician to check the internal wiring before turning anything back on. 

Check your insurance
Check your home insurance policy to find out if your solar system is covered in the case of flooding. 

Check for flood warnings in your area
Check whether there are any current or future flood warnings and register to receive updates. 

How to reduce the risk of flooding damage

• Locate a high point of your property to install ground-mounted solar panels.
• Raise the panels off the ground using heavy-duty anchoring and racking systems.
• If the terrain is low-lying, mount sensitive components like the inverter or data collection devices on higher ground.
• Work with your installer to create a system with stormwater runoff plans or retention ponds. It’s important to make sure there’s an emergency drainage plan in place and to set up temporary drainage before it rains.
• Raise the finished floor levels to a minimum of 150mm above existing ground levels. 
• Make sure to locate vulnerable equipment away from areas where flood risk is higher. 
• Ensure electrical connections are sealed. Seal all entry points and electrical connections to prevent water from getting in. Check the sealing and insulation of all the electrical equipment.
• Standard practice when preparing a site for ground-mounted solar systems results in topsoil loss, compaction, and sometimes use of gravel, and or geotextile weed cloth, greatly reducing the ability of the site to absorb stormwater. This can be remedied with the use of deep-rooted pollinators and native plants which can increase the ability of the site to absorb a greater amount of stormwater. These plants loosen soils allowing stormwater to soak in, and the plant roots also absorb a large amount of water. Stormwater can be reduced by as much as 38% using this strategy. Ideally, a solar PV system should be designed to support pollinator plantings. However, existing systems might be able to sustain pollinators around the perimeter and possibly between rows.

As the solar power industry grows in the years to come the standardisation of testing, energy conversions, use of materials, and health and safety practices must be applied consistently across the sector if we want to reduce the risks involved in the harvesting of green energy and see these installations achieve their full potential.