Module mounting structures have an important part to play in the functioning of a solar power plant. They are the supporting structures that hold solar panels to the ground. In order to harness solar power efficiently, mounting structures need to be manufactured and installed at sites in a specific way. However, the quality of mounting structures is often compromised to cut costs.
To fully utilise the solar potential of a large number of solar projects, it is important to make them efficient and well constructed. For a project to be robust, the solar panels must be mounted properly in order to absorb the maximum amount of sunlight as well as withstand environmental pressures. Solar panels are not directly attached to the ground or rooftops; rather, they need to be mounted on supporting structures. Mounting structures for solar panels are useful in securing them safely on the surface of the installation. They are usually placed in a way that allows the solar panel to get maximum inclination angle on the surface. Solar module mounting structures can be used for rooftops, ground mounting, carports and tracker solutions. Floating solar projects are also emerging as an area of application.
Mounting structures need to be durable to be able to bear the weight of solar panels, high wind speeds and a range of temperatures. In order to adapt to topographical features and weather conditions on site, module mounting structures require customisation.
Types of mounting structures
Mounting structures have evolved over the years in terms of weight, material, adaptability and cost, making them durable so that they can withstand the weight of solar panels. Large photovoltaic (PV) modules are more likely to encounter vibration problems and the possibility of being blown away by strong winds. This has led to an emphasis on strengthening of mounting structures. Further, mounting structures of proper quality must be able to endure high wind speeds and a range of temperatures. They require customisation to adapt to the topographical features and weather conditions on site.
A solar power plant is designed to last about 25 years, making the supporting structure a crucial factor in its long-term performance. It is thus important to choose the correct type of mounting structure. There are five types of mounting structures – roof-mounted racks, ground-mounted racks, top-of-pole-mounted racks, side-of-pole-mounted racks and tracking system-mounted racks. Of these, four are fixed-angle type and one is variable-angle type.
Roof-mounted racks are used for rooftop solar projects. They can be fixed or adjustable and even be installed with a solar tracker. Ground-mounted racks are usually adjustable and allow panels to tilt up or down for maximum solar absorption. There are two varieties of pole-mounted racks. While one allows the solar panel to sit on top of a pole, the other elevates it several feet off the ground. Tracking system-mounted racks can be used for solar tracking systems and solar water pumping systems.
Such solar projects typically use foundation mounting structures. In the process, land is excavated to put in vertical pipes, surrounded by a concrete foundation. Other types of ground-mounted structures are ballasted and pole-mounted structures. In ground-mounted structures, the pole-mounted racks are usually adjustable and allow panels to tilt up or down for maximum solar absorption. There are also tracking system-mounted racks, which can be used for solar tracking systems and solar water pumping systems. Even among ground-mounted plants, mounting structure designs can differ on the basis of land technology, soil type and other weather-related parameters.
Rooftop solar projects use roof-mounted racks. To mount solar panels, techniques such as rail mounting, where panels are attached to the rails using clasps; ballasted mounting, in which panels are directly fixed to the roof through hardware; and shared rail mounting, where two rows of panels are attached to the same rail are used. Another common technique is mounting solar panels on elevated structures. In an elevated structure, panels are installed at a height of 12-15 feet. This is often preferred by consumers, as it does not take up the entire surface space and can also act as a shed-like structure on roofs.
Mounting structures for floating solar plants are also coming up. These rely on a special mounting system design, which prevents contact between solar panels and the surface of the waterbody. Mounting structures for floating solar can be helpful for installing solar projects on water surfaces such as ponds, rivers, reservoirs and off shore PV applications. Among recent developments in this space, Chinese mounting system provider Mibet has developed a structure for floating PV installations designed to endure low temperatures and withstand wind and snow loads of up to 42 metres per second and 1 kilonewton per square metre respectively.
Under the Make in India initiative, there has been greater emphasis on local manufacturing of solar components. Module mounting structures, which make up 9-15 per cent of the total project cost, are also increasingly being manufactured locally. As per industry estimates submitted by Loom Solar, module mounting structures account for 9-15 per cent of the total cost of a solar power plant, depending on the size of the plant. In smaller plants, mounting structures make up about 9 per cent of the total project cost. Hence, module mounting structures can cost anywhere between Rs 3.60 per Wp and Rs 6 per Wp for a 1 MW solar power plant of Rs 40 million.
According to Future Market Insights, the market for PV mounting systems is set to expand during 2021-31 at a compound annual growth rate (CAGR) of 10-11 per cent. According to their report, the key growth drivers will be the increasing demand for solar power, and the rising power demand in urban areas. During the pandemic, disruptions in supply chain processes impacted the market to some extent. The report mentions that the global PV mounting system market witnessed a substantial dip in year-on-year growth in the year 2020, owing to the nationwide lockdowns and supply chain interruptions caused by the Covid-19 pandemic. Meanwhile, the demand for mounting structures is rising, as evidenced by the increase in demand for structural components for rising solar capacity.
According to their report, the key global manufacturers and suppliers of solar mounting structures are: Schletter Group, Unirac Inc., SolarWorld AG, K2 Systems GmbH, Quick Mount PV, Land Power Solar Technology Co. Ltd, RBI Solar Inc., Mounting System GmbH, Xiamen Grace Solar Technology Co. Ltd, Clenergy, Tata International Ltd, Xiamen Universe Solar Tech. Co. Ltd, Xiamen Corigy New Energy Technology Co. Ltd, PV Racking, Van der Valk Solar Systems BV, amongst others. The key manufacturers in India include Tata international, Jakson, Metalkraft, Strolar, Neuvosol, SNS Corporation, Ganges International, JSW Steel and Pennar Industries.
According to Global Market Insights, the market size of solar PV mounting systems in 2021 was valued at $15.3 billion and is estimated to grow at a CAGR of over 3 per cent between 2022 and 2028 reaching more than $21 billion in 2028. According to their report, a continuous development of high efficiency systems, consumer shift towards sustainable energy, decline in component costs and rising electricity demand will accelerate the market growth.
Given the ambitious targets for solar power capacity in India, the market for solar components, including mounting structures, is expected to grow. Since they form a significant part of a solar plant’s cost, deeper innovation will be needed in material and structural design to bring down costs and make the structures resistant to harsh conditions.