We subscribe to the 6P principle: Proper Planning Prevents Piss Poor Performance
Before signing up for solar, putting down a deposit, and ordering equipment, it is prudent to conduct these 3 assessments. These are relatively inexpensive and are guaranteed to save you headaches in the long run.
- Roof structure and condition assessment
- It is important to check whether a roof is strong enough to handle the extra load of solar panels on the roof. On average, the weight load is around 13 kg/m2. To put that into perspective, a 100kWp system can weigh an extra 7,800kg.
- The roof assessment must be conducted by a certified structural engineer and should reference the panel layout on the roof.
- If the roof is not strong enough, intervention can be taken to reinforce it or abandon installing the solar system.
- It is also advised to repeat the exercise every 4-5 years after the solar system is installed.
- The condition of the roof surface should also be inspected prior to installation. Remember that a solar system is a 20+ year investment. Replacing a roof after solar PV has been installed is not ideal. Metal sheeting roofs that are old and rusted may need to be replaced before commencing with a solar installation, or in some cases refurbed with a suitable coating.
- Wind load assessment
- Some solar panels are mounted flush and others are raised at an angle to maximise the solar yield. Panels that are raised at an angle are more exposed to wind forces. Verification must be done to confirm that the mounting structure can hold the panels down on the relevant roof and that the roof can withstand the wind forces that are prevalent in the area.
- The supplier of the mounting structure should provide this confirmation based on the panel layout and the dimensions of the building.
- Lightning risk assessment
- South Africa is not for sissies; lightning strikes here are approximately 4 times higher than the global average and account for over 65% of all over-voltage damage to electrical infrastructure. Yet this is often over-looked when designing and installing a solar system.
- Some regions are far more prone to lightning than others, requiring more robust protection for systems located there. Your solar provider should offer that a certified lightning expert to conduct an assessment in advance, which will determine the level of lighting and surge protection that should be included in your proposal.
- By doing this upfront, the solar provider can then accurately cost the required protection into the proposal upfront instead of figuring it out after your inverter has been fried.
For more information, you can contact SAPVIA (The South African Photovoltaic Industry Association) and request their PV Green Card installer guidelines.