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Inverter technologies, String inverters v/s central inverter – EQ Mag Pro

Inverter technologies, String inverters v/s central inverter – EQ Mag Pro


The webinar was held by EQ Magazine Pro on March 22, 2022, powered by Growatt on the topic of ‘PV Inverter and BOS Tech’, moderated by Praveen Vaishnav, AGM, ReNew Power Private Limited. In this webinar, panelists discussed inverter technologies.

Praveen Vaishnav, talked about the string inverters and central inverters. He said, “The basic question in this industry is whether it uses a string inverter or a central inverter. We generally prefer string inverters from our evaluations. There are three parameters which we generally check, first is the inverter cost, in which the central inverter is in the upper hand because these are cheaper than that of the string inverters.

If we consider BOS cost then we are using from three to four years and we do have many in-house optimization programmes by which we have been able to get a better BOS in a string inverter than that of the central inverter so there are string inverters are having an upper edge over the central inverters and then there is also a point of generation yield for which string inverters are substantially better than that of central inverter because of multiple MPPT functionality. So, if we just go on the benefits of the string inverter we can see a few major points like higher yield but it depends upon project location, second is lesser BOS cost obviously because of savings in DC cable quantity, also there is benefit of natural cooling and fast installation as well. The efficient accuracy of the string monitoring with string inverter. It’s much easier to do so, if we go with the central inverter then we may need a bit higher efficient junction boxes for this.”

Sudhir Pathak , Head, Central Design & Engg (CDE), Hero future energies, put his views on inverter technology and BOS. He said, “Now, block sizes are growing, which means the usage of plants is growing many folds. Also, we need to make our systems future ready because in future all the modules will be bifacial. So we need to take each module or each string as an Independence entity rather than taking the complete plot as a single entity. Now, with the data analytics and the size of the plant being 600 megawatt we need to utilise a digital technology where we can access the behaviour of each module by digital tools not through the manual tools. Also, string inverters are easily replaceable.”

Shantanu Sirsath, Technical Head India, Growatt New Energy gave a brief about the products and services Growatt is offering. He said, “Growatt is a global manufacturer of PV inverters and energy storage solutions and our vision is to become the world’s largest supplier of smart energy solutions. And for this, we are committed to provide clear and convenient access to green energy. At Growatt we are focusing on innovation as well as excellence. Growatt was founded in 2010 with an USD capital of $20 million. It is a new energy enterprise which is dedicated to R&D, manufacturer of string inverters and energy storage solutions.”

Talking about the milestones that Growatt has achieved in the last ten years, he said, “Growatt was founded in the year 2010 and in the year 2011 it was one of the earliest exporters of string inverters in China. In the same year, we came up with different subsidiaries in Australia, Germany and Hong Kong. In 2012, we became the number one brand for the string inverter in China. In 2015, we were the one of the suppliers who have launched the residential hybrid storage inverters for the global market. In 2016, we became the number one brand for the residential inverters in China. In 2017, we reached the milestone of shipping more than 1million units to the global market. In 2018, we were in the top ten provider of PV inverters in the global market and we were the number one for the supply of inverters in the residential segment.

In 2020, we came up with a new manufacturing facility which has an annual production capacity of 20 GW and by the end of year 2021, we have more than 3.5 million units for the global market. Every year we are having an annual CAGR of around 40% and in the year 2021, we did a total overall business of more than 500 million USD. We are a team of more than 3000 employees worldwide, out of which we have dedicated more than 400 employees only for the R&D and every year we are spending around 6.1% of the total revenue only for R&D purposes. We have our reach to more than 110 countries worldwide by the end of 2021 we have shipped more than 3.5 million units which aggregates to around 37 GW of supply of inverters globally.

Talking about Growatt’s presence in the Indian market, he said, “For the last three years, we are ranking number one for the supply of inverters in the rooftop segment. We have a total market share of more than 18%. And for the Chinese market we have a market share of more than 35% which means every third inverter that is installed in China is of Growatt. In the last five years, from 2016 to 2021, we have invested more than $100 million only for R&D purposes. Also, we have more than 110 patents to our name out of which more than 60 are Chinese patents and 40 international patents. We have more than 20 software copyrights. We have established a research centre along with NEPCC with China’s Ministry of Science and Technology. Also, we have set up a joint research lab with Texas instruments for different sustainable energy applications. “

Talking about the global presence, he said, “We have 23 offices and warehouses worldwide. We came to India in 2013 and we’re the only company which had two service centres in India, in Hyderabad and in Ahmedabad. For monitoring, we have different devices which can work on Wi-Fi, GPRS, 4G for a single inverter monitoring or one can go with our data logger or smart energy manager with which it is possible for you to connect up to 64 number of inverters. Also, we have our own portal, server and mobile application which is useful for monitoring your plant from anywhere in the world.”

Sachhin Patra, Senior Manager, EnKing International (EKI Energy Services Ltd), put his views on the carbon offset management in front of the panellist. He said, “From the carbon offset perspective, it’s very important for renewable energy projects nowadays, because it can form an important part of your long term cash flows. As the market has grown and become robust in the past few months specifically last six to twelve months.

There is an increased accuracy in which you can forecast your cash flows of carbon offset and that can become an important part of your cash flow estimates on the basis of which the valuation of the project depends. It’s more important for the inverter manufacturers to understand what kind of data integration they can do which can help the project developers get carbon offset because in case of carbon offsets, the main data that we need is the generation of power from the projects.

That’s one of the important data that the inverter captures. So, capturing those datas and calibration reports of various instruments which can increase the accuracy of the inverters and equipment is for verification of the data before issuance of the carbon credits. Carbon credit is given on the basis of historical performance so you have to submit the data generation and then on the basis of that the project developers get carbon offsets.”

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Anand Gupta Editor - EQ Int'l Media Network