FRP and the ‘No pains, All gains’ proposition for rooftop solar power.

SOLAR POWER

FRP and the ‘No pains, All gains’ proposition for rooftop solar power

Mr. Ankur Kothari, Chief Operating Officer - ‎Arvind Composites, Part of Arvind Limited

GI (galvanized iron) or MS (mild steel) materials used to design solar rooftop structures have two fundamental drawbacks; they are heavy and prone to corrosion. The search for a material that is both light and maintenance-free ends with fiber-reinforced plastic (FRP). FRP is a lightweight alternative to steel and doesn’t corrode even when exposed to harsh environmental conditions.

In the last decade, the installation of rooftop solar panels on industrial and residential buildings has grown at a rapid rate. The continuing fall in costs of panels and the promise of low-cost electricity,which reduces dependence on the grid, have led to a boom in these installations. Solar panels mounted on a structure are now a common sight around the country. As the number of installations increases, these structures have undergone several modifications. Most designs,today, are lightweight and have protective coatings to ensure a life-span of more than 25 years.

However, the GI (galvanized iron) or MS (mild steel) materials used to design these structures have two fundamental drawbacks;they are heavy and prone to corrosion. And so, sometimes, even though owners may want to install rooftop solar panels, they are unable to do so because their roofs aren’t designed to bear the weight. Furthermore, these structures require frequent checks and maintenance to ensure that they meet their design life. It is common to hear of structures that fail,or which need to be replaced within a span of five years. With labour costs increasing every year, this makes it an unviable proposition. In an ideal scenario, one would want to install the structure on the rooftop and forget about it.

The search for a material that is both light and maintenance-free ends with fiber-reinforced plastic (FRP). FRP is a lightweight alternative to steel and doesn’t corrode even when exposed to harsh environmental conditions. It is a composite material manufactured by the combination of glass and polyester,with the same mechanical strength as steel but half its weight. This is because FRP’s density is one-fourth that of steel, but its mechanical properties are much better, resulting in a superior strength-to-weight ratio.

The production and the usage of this material has become widespread with time, leading to a significant reduction in cost and making it affordable for various commonplace applications. In the last few decades, the use of FRP has become commonplace for structures such as cooling towers, hand-rails, walkways, platforms, etc. FRP has become the material of choice for civil engineers in applications where lowweight and weatherability are important considerations.

Today, when there are designs and plans for making complete warehouses and industrial sheds using FRP, we are extendingthe benefits of the material to the rooftop solar industry with a design that replaces the MS in these structure with FRP. The entire structure can be built with FRP in a manner that optimizes the non-corrosive properties of the material. The weight of the structure will be half that of an equivalent MS structure without compromising on the load factors required as per government norms, and will have a lifespan of more than 25maintenance-free years. Such a structure is strong enough to withstand winds of more than 170 km/hour. Moreover, it is easy and fast to install, as it involves bolting and riveting as opposed to the welding requiredfor steel structures.

While the weight of a typical MS structure would be more than 100 kg for a standard 2.4 KW household rooftop structure, the equivalent FRP structure will weigh less than 50 kg. This means that we can double the solar panel carrying capacity of the rooftop by using FRP. Not only that, FRP doesn’t need the kind of frequent maintenance that becomes necessary for MS structures after a few years of the installation. Thus, from the perspective of the total cost of ownership, FRP becomes a preferred choice to the existing alternatives for rooftop solar structures. This is especially true if the roof is weak or old, or located near to the coast or inside a plant where it is constantly exposed to chemicals. Owing to its lightweight nature, FRP is also preferable in case the installation is required in hilly terrain or at a location that is difficult to reach.

Today, when technologicalinnovation is at driving the solar revolution, it is only fitting that a new-age material like FRP should find its place under the sun.