SMA’s revamping operation on SOLAR21 PV systems


Following the results from initial revamping activities on three plants operated by BFP Service in Lecce, SOLAR 21 has rolled out the revamping at three adjacent plants.


SOLAR 21 carried out revamping operations on its six ground-mounted photovoltaic plants, acquired in 2012, in two phases between 2016 and 2017.

Although operational, the plants were experiencing some technical issues related to the installed conversion system and the electrical systems supporting it. The issues were causing important production losses due to the low operational availability of the inverters. In addition to the revenue losses due to the shortfall in production, SOLAR 21 had to bear the costs of paying the providers of the out-of-warranty technologies and for urgent maintenance interventions.

The Solution: two phases of revamping

Having noted the production losses and running costs for installed conversion technologies, BFP Service together with SMA Italia’s Application Engineering and Project Management division defined the architecture of the inverter solution to be installed. The solution proposed was the use of SMA Sunny Central CP inverters.

The first phase of revamping took place in April 2016 in three plants: Litarà, Lena and Lamelle – respectively 999 kWp the first two and 760 kWp the last one. The replacement and activation of the inverters were completed within a few hours, resulting in only one and a half days’ shutdown.

Following the first phase of revamping, the Performance Ratio comparison – carried out by comparing the data of the Lena plant (already revamped) with those of the S. Alieni plant, which are about 900 meters apart – showed an improvement of about 3% with an improvement in the annual operating availability from 89% (approximately 40 days per year of machine stoppage) to 99.75%. This is equivalent to an increase in the annual kWh/kWp energy production of 13%.

The strong results of the first phase convinced Solar 21 to proceed with the second phase of revamping in January 2017 on the Milligrani, Badessa and S. Alieni plants – respectively 999 kWp, 999 kWp and 760 kWp. In this second phase, the revamping works were again completed in a day and a half with only a few hours’ shutdown.

The results

In the first months of operation with the new inverters, which were now close to 100% availability, SOLAR 21 recorded a 10% increase in production compared to the 3% increase in production that had been estimated. The result is certainly remarkable, considering that the modules are still the ones originally installed.

The Solar 21 inverter revamping case study will be presented in detail at the SMA Sunny Days event in Rome scheduled for 7th November. Participation in the event is free of charge upon registration at

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