Mounting structures are the backbone of a solar power plant as they provide support to modules. These support structures raise solar panels at appropriate angles to ensure that they receive maximum solar irradiation. Without these, solar panels are not able to capture the required quantum of solar radiation for optimum solar generation. Proper alignment and arrangement of mounting structures are one of the key indicators of engineering, procurement and construction (EPC) contractors’ competency. Despite that, mounting structures do not get the same attention that modules or inverters do. In fact, many EPC contractors continue to deploy substandard mounting structures that cannot withstand harsh environmental conditions.
Materials and types
A good mounting structure can not only bear the weight of solar modules, but can also withstand extreme weather conditions like storms and floods. A variety of materials ranging from wood to polymers have been used to create strong and durable mounting structures for solar panels. Stainless steel has been the popular choice in most cases. Given the plant location and life cycle, stainless steel has traditionally been the most cost-effective option. However, recent trends show an increased utilisation of aluminium in hot dip galvanised state along with steel for better protection against rust formation.
Primarily, there are two types of mounting structures depending on the tilt of solar panels. Fixed tilt structures are installed at a fixed angle linked to the latitude of the place, facing south in the northern hemisphere. Seasonal tilt structures can be adjusted seasonally allowing panels to capture optimum sunlight. While most solar plants have fixed or seasonal tilt structures, many installations also use tracker solutions to change the orientation of solar panels as per the season and time of day to capture optimum energy. However, the high additional upfront costs associated with trackers have somewhat limited their uptake. Technology innovations in the mounting structure space are focused on changing the structure to optimise costs. For instance, mounting structures with rails provide durability and support to modules while rail-less mounting structures can reduce the installation costs to some extent owing to low labour requirement.
Mounting structure design varies in different solar plants based on the project’s location, application, terrain and environmental considerations. Thus, different mounting structures are used for ground-mounted, rooftop, canal-top and floating solar plants. Even among ground-mounted plants, the design of mounting structures can differ on the basis of land topology, soil type and other weather-related parameters. The complexity increases in rooftop solar plants as rooftops can be flat, inclined or corrugated, made of concrete construction or metal shed. Mounting structures need to be designed differently for each roof to ensure maximum energy yield. For instance, mounting systems deployed on angled roofs require anchoring. They can be attached to rafters or a deck. In contrast, flat rooftops have ballasted mounting structures with few penetrations. Solar shingles are building-integrated photovoltaic (PV) solutions, which become a part of the roof structure and do not require mounting structures.
For canal-top solar projects, lightweight mounting structures need to be developed that do not adversely affect the structural integrity of canals. For floating solar projects, steps need to be taken to prevent the corrosion of mounting structures. The solar PV industry has indeed advanced to a stage where no location is unsuitable for solar plant installation. Solar PV projects are being commonly installed on water reservoirs, car parking spaces and even trains. For each of these, mounting structures need to be customised as per the requirements and site conditions. This incurs additional costs as using a one-size-fits-all solution might compromise project quality.
Since India is a highly price-sensitive market with ultra-competitive solar auctions, developers need to take certain cost-cutting measures. Moreover, solar power tariffs have become unsustainable for many small power producers. Thus, in order to prevent larger hits on their profit margins, developers compromise the quality of mounting structures as well as other components. Quick-fit design concepts have flooded the market, which though cost competitive may not adequately meet the exact project requirements. As per industry reports, the standard thickness of mounting structures has consistently decreased and manufacturers are resorting to low grade raw materials to save material costs. All these measures affect the long-term durability of mounting structures, which may result in significant maintenance costs.
The mounting structure market is a highly fragmented market with over 60 suppliers of solar mounting structures active in the Indian market as of end 2018-19. According to Mercom India, the 10 leading mounting structure companies in India accounted for 65 per cent of the total market share in 2018-19, while 50 or so suppliers accounted for the remaining 35 per cent. Of the 10 leading companies, three companies shipped over 500 MW of products while two shipped about 1 GW of mounting structures.
With unprecedented growth witnessed in the solar power segment, the majority of the steel giants around the world have started supplying mounting structures. JSW Steel Coated Products Limited is one such example. A 100 per cent subsidiary of JSW Steel, it is an established name in the solar mounting structure space. Pennar Industries, a market leader in the solar mounting structure business, also has a steel products division. The company derives over 30 per cent of its business from the solar mounting structure division. SNS Corporation and Ganges Internationale are two other leading players in the mounting structure space. Other large players in the mounting structure space include Tata International, Jakson, Neuvosol, Metalkraft, Strolar, and Solar Mounting System Solutions.
The solar power segment witnesses regular entry of new players. Large established players have been able to sustain themselves despite low returns, while small suppliers are grappling with challenges posed by the unavailability of raw materials, fluctuation in prices and the high cost of labour. Thus, these small players are most likely to exit the mounting structure space or get acquired by larger players with deeper pockets.
As per industry estimates, 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, while their share increases in larger plants. 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. Between 2013-14 and 2016-17, the industry witnessed a significant decline in prices, from Rs 10.5 million per MW to Rs 3.5 million per MW as per the Central Electricity Regulatory Commission’s benchmark norms for solar PV projects. However, the costs have not declined in the past two to three years unlike the trend in the solar equipment market. The costs have fluctuated due to the fluctuation in the cost of raw materials like steel and aluminium.
Given the rapid increase in solar power deployment across all applications, there is an incremental demand for related equipment at cost-effective prices. Thus, the market for mounting structures is also expected to expand in the coming years. In fact, the rooftop solar segment is likely to reach a market size of Rs 40 billion-Rs 140 billion by the end of 2024-25. The demand from the utility-scale solar segment is expected to be even higher. Other applications such as floating solar and canal-top solar are also going to witness increased uptake, which will drive up the need for specialised mounting structures.
With falling module and inverter prices, the focus of cost optimisation is now shifting to other balance of system equipment like mounting structures. In order to reduce project costs without compromising the quality and durability of these structures, equipment suppliers are improvising their structure designs. New materials are being tested and structural changes being made to make more cost-effective products, which can help sustain the low solar power tariffs. However, many suppliers and contractors are also trying to cut corners by opting for sub standard equipment to stay afloat. This practice needs to be discouraged. Solar project developers should put in place stringent quality checks even if the upfront cost is a little higher.
In sum, the demand for mounting structures of all types and sizes is set to witness a surge. That said, a high degree of innovation will be required, both in structural design and materials used, to make mounting structures available at cost-competitive prices.
By Khushboo Goyal