'Central vs String Inverters: Choosing the Right Solution for Industrial Solar Installations’

February 26, 2024. By News Bureau

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Central Inverters

The Solar energy space across the world is fast gaining popularity. According to reports as of November 30, 2022, India had 61.97 gigawatts (GW) of installed solar capacity, placing it fourth globally for solar photovoltaic (PV) deployment.

This places India at the top spot in terms of turning towards solar energy. The recent interim budget presented by the Government of India too has shown a strong political will to popularize solar energy in India. An allocation of a whopping The Solar energy space across the world is fast gaining popularity.

According to reports as of November 30, 2022, India had 61.97 gigawatts (GW) of installed solar capacity, placing it fourth globally for solar photovoltaic (PV) deployment. This places India at the top spot in terms of turning towards solar energy. The recent interim budget presented by the Government of India too has INR 10,000 crore for solar (grid) for 2024-25 has been made against INR 4,970 crore in 2023-24.

As the country progresses in its journey towards sustainable energy, there are many learnings that the industry stakeholders need to pick up as they go along. A significant amount for energy consumption is from the industries, making industrial solar projects important for India. Among the very basic questions that always come up in solar installations is a choice between Central Inverters and String Inverters; and to make this choice one has to understand the business model that is being used for the projects.

A solar inverter is called the heart of the PV system. And as everyone would tell you the basic role of an inverter would be to convert the Direct Current (DC) generated by the solar panels into Grid compatible alternating current (AC). But with advancement in the renewable technologies, the role the inverter has grown in more critical areas of supporting and controlling the grid; and it is important for people to understand the pros and cons of inverter technologies so as to make an informed decision about inverter selection for their project.

Central Inverters: Cost Effective with Grid support
Primarily used in the utility scale PV projects, the central inverters provide a cost-effective solution with simple system architecture with dynamic performance. It is the oldest and hence proven technology which has been able to adapt to the new trends in the world energy market. It can provide the future viability with regards to the grid management support that it can offer. With the fewer electronic components at site, central inverters are able to provide reliable energy to meet the customer needs. On the other hand, the mere size of the central inverters imposes limitations on transportation and installations during the project execution for the industrial applications. Hence the central inverters would be best suitable for large ground mount industrial projects connected to the MV grid.

String Inverter: Distributed Generation with Design Flexibility
As the name suggests, the String Inverter is directly connected to the multiple strings of a solar array. The biggest advantage of String inverters is the ease of installation. Due to the smaller capacities, string inverters offer higher design flexibility making them better solution for distributed rooftops in industrial PV plants. The maintenance and replacement in case of failure is much easier with the string inverters. But with more power electronics components on the field, the communication and control of the overall system can be a challenge, specially in the industrial environments. Considering all the properties of the string inverters, they are better suitable for rooftop PV projects with industrial loads running at the low voltage grid. Future expansion of the project also becomes much easier with the string inverters projects.

The average project size of the industrial projects has seen a steady growth along with project complexities as the industries are seeking for sustainable future with renewable energy integration. In the Industrial PV project business worldwide over the past few years, many business models have been tried and tested by global player depending upon the investment capital, the available space for PV installation, and the most importantly, current renewable market policies in the region.

Perhaps a definite ‘one above the other’ choice will be a difficult one, but the choice of business model and the kind of installation ecosystem available at that point of time will be the major factors to determine the final choice.

- Priyamvada Pandit, Technical Sales Support Manager, SMA Solar India