Technological advancements in the solar power segment have significantly reduced system costs, thus increasing installations across the globe. To achieve maximum technical, financial and physical project efficiency, developers are expected to rapidly adapt to these technical changes, creating significant system integration challenges. Integrating modules with the balance of system (BoS) to increase the efficiency of not only individual components but also the entire system is becoming more challenging in the face of land issues, changing weather conditions, location diversification and financial constraints.
According to Aaron Wu, general manager, Phono Solar Technology, SUMEC Group, system integration can be improved via three modes. The first is to change the physical system, which includes customising the existing components to accommodate new technologies such as the new 1,500 volt modules, or smart junction boxes instead of traditional ones to reduce labour and BoS costs. The second option is to upgrade the technology to improve efficiency as well as power output, subsequently reducing the levellised cost of energy (LCoE). The third mode includes integrating various components to create synergies. This requires creativity on the part of the design engineer.
According to Hank Wang, vice-president, international business development, Sungrow Power Supply, the needs of the industry have changed over the years. Good quality equipment, high efficiency, fast service and competitive pricing have become standard operating procedures, thereby requiring companies to focus on innovation and diversification in system integration. Given the scarcity of land in the country, the conditions for plant installations are also changing from plains to deserts and mountains and to various types of rooftops. “For instance, central inverters are used for large ground-mounted systems where the land is flat in order to save on capital expenditure. However, if the project is being set up in hilly terrain, a virtual central solution would be required, which includes bringing together large capacity string inverters to save on cable costs and maintenance expenditure over the lifetime of the system. The idea is to enable scientific design-based upliftment of the product while fulfilling all system requirements to contribute to system integration and optimise the returns on investment for investors,” says Wang.
The use of system integration in the solar segment, which is currently facing diminishing margins, is imperative to save not only capital costs but also operational costs over the lifetime of the project. Two levels of integration currently exist in the market, notes Guy Rong, president, Arctech Solar. At the simple level, it involves making a few modifications to the existing technology. An example of this could be leveraging the synergies between inverters and trackers. The tracking device can get the required power supply from the inverter as well as use its communication device, thus reducing the cost of cables, UPS devices and communication technology. The other level of integration entails complicated adjustments and redesigning. Given the different types of terrain where solar projects are deployed, there is a demand for innovative solutions. “Solar plants located in sandy regions suffer from reduced generation due to layers of sand and dust deposited on the face of the panels,” says Rong. “While automated cleaning can be useful for a small project, a 100 MW plant would require a large investment. Also, with bifacial modules now being introduced in the market, which could be commercialised within the next two years, developers will have to innovate their systems to integrate these. Most tracker companies design the system in a way that only a single module file can be installed in one row, which creates a shadow on the back. To integrate bifacial modules, the current system will have to be redesigned.”
Owing to the increase in solar power plant capacities, from a few kilowatts to over 100 MW, the issues in system development and integration have also changed. Whereas earlier integration was limited to a simple combination of components for a small plant, today considerable effort is required for the deployment of new large-scale systems. Rahul Kshetrapal, general manager, Sterling and Wilson, highlights the challenges pertaining to rapid revisions in technology, which have reduced the adoption time and shelf life of the technology. He says, “While earlier grid integration did not consider parameters such as power factor control (day and night), reactive and active compensation, these are now evolving for the modern grid to accommodate variable and uncertain power from renewable sources of energy. This poses another major challenge for system integration of upcoming plants.”
Moreover, along with the increase in project sizes, the time-to-market for solar plants is constantly reducing. In addition, sourcing of land of different contours and soil conditions is a challenge that needs to be solved within limited time. This exerts considerable pressure on developers and design engineers to develop optimum system integration procedures for smooth acquisition of land and execution of the project. Therefore, there is a need for innovation in project execution models and optimisation of construction costs. “Managing the LCoE of projects has become vital for investors, and the only two ways to achieve this are by increasing output and reducing costs,” says Kshetrapal.
Other challenges relate to the monitoring and control of projects. Harikrishna Kadapurath, senior general manager, Greenko Group, notes that the industry lacks effective monitoring solutions to manage the increasing volume of modules and inverters in a solar power plant. Further, he says, “The poor quality of plant construction due to unskilled labour is another significant challenge faced in the integration of new technologies, such as robotic cleaning.”
Sanjeev Kumar, general manager, solar division, Greenko Group, says that system integration challenges vary according to the size of the project. “Bigger projects require greater control to reduce the dependence on contractors, which adds to capital costs. However, such investments are not possible for smaller projects and hence, the developer or client’s control is compromised.” Finding skilled labour, especially for technical tasks such as testing and commissioning of the plant, is becoming increasingly difficult owing to the large projects being executed simultaneously. Logistics and supply chain issues are also prevalent in the solar industry.
Recommendations and outlook
The Indian solar industry is looking at best practices in international markets to enhance its system integration processes. The role played by the government in quality control of equipment in China can be replicated in the domestic market to ensure that no substandard equipment is used for upcoming solar plants. The European market prioritises tasks and executes them in a planned manner during project execution. For instance, companies get a complete understanding of the project on the first day of construction as opposed to some of the Indian developers who achieve that level of information about 10 days after the commencement of work on the project. In addition, placing purchase orders after completing the engineering and design phase would help avoid cost overruns. System integration should be done in an organised manner and across all contours of the project to achieve optimum cost and effort utilisation.
Considering the changing climatic conditions, innovations such as bifacial modules and double glass panels will see increased adoption in the near term. While trackers have so far seen limited uptake due to land constraints, the trend is now changing with more projects embracing the technology. Inverter costs are expected to reduce by about 10 per cent per annum. However, with the decline in capital costs, tariffs and investor returns are also falling. Therefore, the industry not only needs to reduce costs, but also save operational and capital expenditure by adopting innovative integration techniques.