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In Exclusive Talk With Mr. Vasan Ramasubramaniyam, MD & CEO, PRETTL India

In Exclusive Talk With Mr. Vasan Ramasubramaniyam, MD & CEO, PRETTL India

  1. How much Inverters have you supplied to India till now, what is the target/expectation in 2017-18

REFUsol, a flagship brands of PRETTL Group, a leading German family owned business house has been active in India through its subsidiary Prettl India Pvt. Ltd since last year July 2016.

We have supplied around 15 MW of REFUsol Inverters since getting active in Indian market. Our goal is to double the sales in this FY 2017-18.

  1. The recent aggressive bidding by various developers keeping Solar Tariffs in the price range of Rs.2.44-3.3 per kWh in various Solar Tenders…Whats your view on the viability, Costs & timeline pressures,

Such an aggressive bidding will not bring long term sustenance for the component suppliers . Infact it will make the small players either wind up or merge with bigger players . I believe that this will also lead to compromise on technology driven components  , as some players who are offering 10 year warranty , with less/no validation proof for such a long period . On the long term, we have to match market changes through make in India.

  1. Resource Challenges (Materials, ManPower, Execution, Grid Connection, Land Possession) etc…

While there will be challenges , in particular on land acquisition , large dependency on imports of parts with long lead time – resulting holding stocks by the component  suppliers – which has a risk of wrong part inventory and  with negative impact on cost . Camouflaging the such indirect cost will be of high risk for mid size players .

  1. Kindly enlighten our readers on the performance of your Inverters in India in various geographic locations, customer feedback,.

Last year, July 2016, REFUsol re- entered Indian market, after a lapse of around half year – We made presence of our reentry, with our participation in the REI 2016. This was well received by many clients .Of the supplies of REFU sol till date we have a positive feedback on acceptance from major EPCs and the end customers. We thank all our clients for patronizing REFUsol . The constant challenge of power degradation with higher ambient temperature at locations where there are high irradiations, also overcome with our new generation Inverters which will be launched in 4 th Qtr this year . In order to bring more flexibility for the System designers with our Inverters and bring a lower TCO , we have brought is some features in the existing inverters – resulting in a centralized concept from the current decentralized version.

  1. Present some noteworthy projects, case studies of solar plants built using your solar Inverters

In the state of Rajasthan we have delivered for industrial consumption 1.3 MW which has high energy yield up to 5.68 Units /Kwh /day – which really proves the high level of efficient Sting inverters . This is our USP. We have also supplied around 5 MW in the state of Ander Pradesh. Currently we are in the process of acquiring of 10 MW project in the state of Telangana. In the western India we have successfully installed about 4 MW projects . All were achieved with our reliable product and experienced on and off field engineers .

  1. Please describe in brief about your company, directors, promoters, investors, its vision & mission

Prettl India Pvt. Ltd is a 100% Subsidiary of PRETTL Group. Led from the front by a visionary Chairman of the group. Mr. Rolf Prettl, the machine is to have a strong foot print of all the major business verticals of the diversified group in India. We have already a strong foot hold in Automotive electronics , with a manufacturing plant in Pune . Also we have around 12 strong R&D  engineers on the energy business in India who supports Prettl Energy globally for  new product development. We  are enroute for a strong market positioning PV string solar Inverters in India with a target to go in local manufacturing ,in support of “ Make in India “ policy of GOI.

  1. What is the size of your company in terms of manufacturing capacities, growth chart, future expansion plans, revenues, shipments, ASP’s, financial figures,

In less than one year of its establishment , our Energy division  in India  targets about 20 MW in this FY 2017/18 in PV inverters business .  Also we plan for local manufacturing , the economic working under progress .  Considering very high level of competitive market , it is important that we also bring more value added service  to our Customers.

  1. What are your plans for India, your view on the GOI target of 100GW Solar Power by 2022

Considering the market potentials and its competitiveness, we are in a process of analyzing for

Local manufacturing the string Inverters.  Though the GOI target of 100 GW by 2020 is challenging, but it gives lot of opportunity for many EPC players to enhance their ability to try out many models of Inverters which can optimize a higher energy yield. Refusol will be one of the keen contender in this scenario.

  1. What are your plans for Manufacturing set up in India, the opportunities and challenges in manufacturing in India

As mentioned above, we are analyzing a business case for local manufacturing. With post GST, we see better economics than pre GST era. As known we have robust European technology However, the concern will be on dumping of goods from those countries where the custom duties are nil or low in comparison with the parts/ sub-assemblies that are needed to assembly & testing locally. Therefore it is paramount important that anti-dumping duty is levied & governed effectively.

  1. Briefly describe the various technologies and its suitable applications such as Central Inverter, String, Micro Inverter, 1500V, Outdoor, Container solutions etc..

We manufacture 3 phase solar string inverters which are highly efficient in terms of PR percentage & energy yield. This is because of our more than 3 decades of experience in  power electronics & innovation. We have patented many of the technologies which give us the niche in the market. WE are developing a container solutions for string inverter which should be in the market in the months to come which will reduce opex cost in comparison with other inverter manufacturers system/ layouts.

  1. How much is your R&D budget as % of your sales / profits

R&D value addition is done in our mother Plant. Currently, most of the revenues are being spent on new technology innovation & the stabilization will take couple of years more to make a meaningful percentage comparison on the expenses on R&D.

  1. What are the top 5 markets for your company in the past, present and future

REFUsol primarily focuses in commercial & industrial scale applications particularly in roof top & utility scale installations. Our product portfolio caters the 3 phase grid connected string Inverter requirements quite efficiently.

  1. Technology road map in terms of 1500V , micro inverters, upcoming game changes technologies

We are currently working on high density power string inverters with a target to compete with central inverters.

  1. Kindly comment of Energy Storage as a game changer, its technology, cost trends…etc…

Yes. For countries like India and its scattered demography in rural & urban areas, and the high power outage, it would be very necessary to bring out energy storage solutions like AC/ DC storage coupled storage solutions which we feel are the right products in the near future in the Indian market. Refu has already developed to meet the market requirements.

  1. Explain various guarantees, warrantees, insurance, certifications, test results, performance report of your inverters

We have complied our Inverters as per the IEC standards that will meet all the requirements of safety and other parameters as demanded by our nodal agencies and  also targeted ‘0 failure rate within warranty period.

  1. Kindly highlight your product, technology & company USP’s, distinctive advantages etc…

Our Inverters are patented with the unique product features such as ultra ETA 5 level topologies, Convectional cool without external fan, compact string inverter design along with Refu Log monitoring system. Our inverters  have won awards on its performance  from a well -known  photon labs at global level.

  1. Do you also bring financing solutions for your customers ?

No, That is not our core business.

  1. Please share information of some new orders in hand.

Refusol has orders on hand to the extent of 30 MW expected before this financial year.

  1. What are the trends in new manufacturing technology equipment, materials, processes, innovations etc…

Use of lithium ion batteries in India will be best known solution for long storage solution. However, with a prohibitory high investment the market is not prepare to take the leap towards these technology. Silicon diodes in the inverter design are also technology which can improve the efficiency of the inverters which however are still on the infancy stage on the Indian market.

  1. Whats your commitment towards the solar sector in India

As REFUsol goal & aim is to provide high efficient DC/AC converters for a longer life- fit & forget/ plug & play. Our “Think Global Act Local” drive within the group is a direct license to travel close to the vision of our GOI.

  1. What will be the cost, technology trends in solar inverters

       The reduction seen in the unit rate of power generation through solar is dramatically reducing and it’s giving rise to big challenge to meet the new target levels. Before any the targets are revised it’s a paramount important that complete chain of solar manufacturing parts/ components are looked with full picture and its impact, so that the sustenance of such of manufacturers/ importers are improving,.

  1. Feel free to add/modify/delete any question.


  1. How has RUMS Bid and SECI Wind Tender Bid has changed the dynamics for Solar & Wind Projects in India. What are the challenges, threats and new opportunities you see emerging now

Not applicable.

  1. What is the impact of RUMS & SECI Wind Bid on past projects and upcoming tenders

Not applicable.

  1. What has delayed the new upcoming tenders by NTPC/SECI and what are the learning’s and take aways from RUMS & SECI Wind Bids

Not applicable.

  1. What are the expectations from Government / NTPC / SECI / RUMS Team

Not applicable to REFUSOL Inverters as a component manufacturer.

  1. What are the expectations from Tech Suppliers like Modules, Inverters, BOS, Trackers etc….Whats the tech solution you thinking of deploying

We as Refusol inverter manufacturers would like to propose that there is adequate government supports for introduction of new technology for example container solutions for string inverters which will optimize the BOS & maximize the energy production.

  1. Are the developers betting on Modules/EPC Prices or Interest Rates ?

Not aware & not in our business scope.

REFUcube – New concept of Centralized String Inverter System Design

In order to optimize string inverter plant designs, REFU Elektronik GmbH – since years focusing on highly efficient and reliable string inverter technology – has conducted several studies and gained interesting insights.

It became clear that a significant potential of savings in string inverter plants can be achieved when grouping all inverters ata singlelocation close to the transformer (or the point of connection to the public grid) reducing AC cabling in favor of DC cabling The benefit is even amplified when using aluminum cables on the long DC homeruns from the field to the inverters. When using high DC/AC ratio of up to 150%, the overall losses of cabling are also reduced.

In a centralized installation approach other advantages of string inverters such as easy maintenance in one place and the reduction of delicate communication infrastructure are achieved.

Compared to central inverters string inverters reduce the risk threatening business plans and/or performance bonds due to the short mean time to repair (MTTR) and easy replacement in case of failure. Higher energy yields and flexibility are achieved by the modular design, for example in non-homogeneously shaped terrains.Increasing divergence of module degradation during lifetime can be mitigated by reorganization of the solar modules on different inverters.

In summary the studies made evident that centralized string inverter plant designs are superior to other concepts (central inverter as well as decentralized string inverter plant designs) in terms of costs, risk reduction, design flexibility and ease of installation.

As a direct result of these studies, REFU has developed and now launched the REFUcube – the first centralized string inverter solution in an ISO container.

REFUcube is available in four power classes – 1, 1.6, 2 and 3 MVA and comes in a 20ft (for 1 MVA) or 40ft container (1.6-3MVA). It includes MV/LV transformer, MV switchgear, LV switch board, DC connection panel, auxiliary transfer and auxiliary switchboard as well as grid protection relay. All components are pre-wired (with DC, AC and data communication) and tested to ensure optimal compatibility andease of installation. It can be transported easily to and handled at the solar plant locationthanks to its low weight and compact design. The REFU CombinerBoxes are positionedclose to the solar panels and therefore allow short PV string cables and only one cablepair (+/–) from each DC CombinerBox to the container.

Thanks to the natural convection cooling of the integrated REFUsol 46Kinverters and the intelligent ventilation concept the container doesn’t require fans or airconditioning for the inverter compartment. This means the need for maintenance is keptto a minimum.

The use of stringinverters in the centralized concept allows on the one hand an easy replacement in case of problems, while on theother hand guaranteeing a continuous operation of the remaining inverters. Therefore theoverall system availability will be close to 100 %. Additionally the design and easy installation of REFUcube provides several areas ofcost savings: the reduction of cabling, minimized set-up and installation effort as well asreduction of commissioning costs.

For more information please see below link:


Anand Gupta Editor - EQ Int'l Media Network


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