Interview: Zouhair Kefi, Senior VP-Segment Energy, PV, Hybrid | REFU

Recently you have launched REFUsol 100K solar inverter, please share with our readers in details about the all-new inverter and its features.

Thank you very much for this opportunity – we are happy to provide you further information.

Our new REFUsol 100K string inverter was launched beginning this year and caught special attention at the Intersolar Europe in Munich this year. The device is based on our new inverter platform, which is not only the basis for solar inverters but also for our new range of battery inverters.

The most obvious special feature is certainly the two-piece design. The ConnectionBox and PowerUnit are two separate items, but arranged behind each other to optimize installation space requirements. In addition, the ConnectionBox serves also as the mounting bracket. This design enables a time-shifted installation and thus cash flow optimisation and extension of inverter lifetime for the customer: The cable connection for the plant can be completely prepared with only the ConnectionBox, the PowerUnit can be hooked up at a later stage with easy plug and play connection to the power unit. This implies also that the PowerUnit can be quickly detached from the ConnectionBox for trouble shooting and measurements without disconnecting the power cables on the DC and AC side, as well as a fast and easy exchange process.

Solar markets expand continuously around the globe and each grid can have different voltages or requirements. Therefore our new device can be used for various grid voltages from 220V to 460VAC, which offers our customers high flexibility, while being able to rely on REFUsol for all plant requirements around the world.

Last but not least our new REFUsol 100K offers easy and fast connectivity for the customer. We decided to simplify the inverter display and provide a smartphone app for commissioning, configuration and monitoring. The REFU App connects via Bluetooth® and is available for iOS and Android smartphones. Besides commissioning, the app also offers a dashboard with the most current data refreshed automatically as well as on overview of error messages, if these occur. Together with the mechanical advantages, this makes the installation of the devices a child’s play.

We are convinced that the REFUsol 100K string inverter is the ideal choice for commercial and large-scale projects combining the special technological features with our 50 years’ experience, German quality and our worldwide presence.

Tell us more about the REFU hybrid 88K battery inverter?

As mentioned earlier, the new battery inverter REFUhybrid 88K is based on the same platform as our REFUsol 100K solar inverter. Therefore, it has the same unique mechanical features that simplify installation and service of the device.

The REFUhybrid 88K is suitable for a wide range of on-grid battery and storage related applications – from 88 kW to megawatt systems. Thanks to the AC coupling possibilities, it can also be easily integrated into existing systems. The REFUhybrid 88K will initially be available for 400V and 200V second-life applications from Q4/2018. Further expansion stages planned for 2019 will round off the portfolio with functionalities for emergency power supply as well as off-grid and microgrid applications.

In which locations are the REFUsol 100K solar inverters and REFUhybrid 88K available, and does REFU plan a more extensive rollout throughout 2018-19?

The REFUsol 100K solar inverters will be available worldwide starting with certification for the IEC markets and then expanding further throughout next year.

The REFUhybrid 88K battery inverter we will be available for on-grid and second-life applications concentrating on certain markets like Europe and Korea in the first step. With the upcoming versions for back-up and off-grid applications, we will then also expand to further markets, which require additional off-grid capabilities.

How has been the journey of company in India so far and how does REFU plans to contribute to this growing market?

We are proud of having a long history in India since the start of REFUsol inverters more than 10 years ago and still have a strong connection with the Indian market.

On the one hand, we have a R&D department in Pune, where our colleagues work hand in hand with the German R&D centre on new developments. On the other hand, we are present in Bangalore and Noida with sales offices of the worldwide Prettl Group (which REFU belongs to) and we provide local service for after sales through our repair centre in Pune.

Based on the current situation we are evaluating further growth and activity potentials in India. As we all know, India is a heavyweight in the solar market and we certainly want to continue down the path.

What kind of market do you see for string inverters as compared to central inverters?

From our perspective, the market is definitely moving towards string inverters. We have recognized this trend already from the beginning of the solar boom and had at this point the biggest string inverter in our portfolio, the REFUsol 20k. Furthermore, already five years ago we have equipped utility scale projects of more than 50 MW with string inverters, and our focus will continue in this direction. Especially in the emerging markets a comprehensive and fast service and the entailing security of supply is from our perspective only possible with the use of string inverters. With the high power classes reaching 100kW per unit, string inverters are perfectly suited even for utility-size scale. There is nearly no difference anymore on the CAPEX, while string inverters offer better OPEX.

Latest research numbers on the share of string inverters compared to central inverters further encourage us that our chosen focus is the right one for the future.

How is the solar inverter market growing in terms of size and geography?

Every research shows a continuous growth in terms of market size, new gigawatt markets keep adding each year. However, we also see an increase in the number of countries using solar energy. We are convinced that this trend will continue, as the potential for solar energy globally is not even close to being exhausted.

The development implies that the solar market is very diverse in terms of geographical location, governmental regulations as well as maturity. The challenge for us as a manufacturer of solar inverters is therefore to adapt our product and sales strategy to the different markets and requirements. Thanks to our long experience and large expertise in power conversion, we are very confident to be well equipped for these challenges.

Are you planning to dive into electric and hybrid vehicle segment? What are the products we are going to see from the house of REFU for these segments?

As most readers probably know REFU only from the REFUsol solar inverters, you might be surprised to learn that we already have a long history in the electric and hybrid vehicle segment. We have been active in the hybridization and electrification of commercial vehicles and mobile machinery for many years now. Our REFUdrive portfolio includes inverter and converter technology in the power range from 3 to 250kW as well as mobile battery storage solutions. Our focus applications currently are port technology equipping e.g. straddle carriers or AGV’s as well as transport & logistics with electric busses or refrigerated trucks. Furthermore our products are used to electrify or hybridize mobile, agricultural or mining machinery.

You see that we use our long expertise to support the environment in different ways – not only by engaging in the energy revolution with solar and storage products, but also by offering environmentally friendly solution for the automotive sector.


This interview was originally published in September 2018 issue of Climate Samurai