The photovoltaic panels we use are manufactured by the German company SOLON SE. The 100% German company SOLON SE has competitive advantages with respect to both the selection of raw materials and the processes applied for production methods and production control. These advantages make its products around 5% more expensive than other German companies, which is something SOLON SE freely admits to. In particular, the “heart” of the photovoltaic panels – the cell – is made by leading companies in the field, such as Q-Cells, Arise, Soland etc.

The high quality of the other raw materials is guaranteed, since they undergo the strictest testing by SOLON SE. SOLON SE tests its products in special artificial ageing chambers. SOLON SE products undergo simulated ageing of twenty-five (25) years, in variable temperature, humidity and pressure conditions within six (6) weeks. When the artificial ageing process is complete, the raw materials are re-tested for sound operation. Aside from the cells, raw materials include EVA, TEDLAR, glass, Junction Boxes, etc. As an example of the strictness of raw material selections processes, SOLON SE has tested and rejected 95% of the EVA (cells, glass, tedlar, etc. welding material) manufacturers it has interviewed. In practice, this means that other companies (SOLON SE competitors) which use EVA made by the 95% that SOLON SE has rejected – a very large number of companies – will have problems with respect to welding quality and, after a certain period of time (after expiry of the product warranty, not the performance guarantee) there will be various problems due to the influx of air and humidity inside the photovoltaic panel. Of course, investors will be unable to claim compensation, since the product warranty period will have expired. Besides the above issues, on which we could expand even further, there are also differences in the production method and in production control.

One example we can quote is that the two SOLON SE production lines, one in Berlin and the other in Greifswald (North Sea), are 100% automated. Particularly in the segment where cell strings (many cells joined together) are created, the welding is performed by a robot. This contributes to stability with respect to the welding method, and, ultimately, to the creation of high-specification strings. In many companies, particularly Chinese ones, this process is performed manually by workers, with low-quality welding equipment and materials; this entails potential problems after the panels have been operative for a few years. This is also explained by the fact that even if everything is done perfectly, the temperature of the welding tool drops after a certain number of welds, and therefore the last weld is never as good as the first one with respect to quality. Finally, SOLON SE is the only company that applies five (5) production controls (including the flash report), compared to other companies that apply only one (1) control, the flash report.

NRG-ORION cooperates with the largest manufacturer of inverters in the world, SMA. Given that SMA holds about 80% of the Greek market, there is no particular reason to expand further on SMA. SMA provides technical support in Southern and Northern Greece and has a satisfactory stock of spare parts (mainly reconditioned inverters) thus giving its customers the opportunity to rectify any damage immediately.

The inverters have integrated energy gauges and are connected in series, using a special cable or Bluetooth, with the webbox, a device that stores measurements per specific times. This data is sent to SMA’s portal (sunny portal) via a GSM modem. We believe that monitoring is very important for the sound operation of a photovoltaic plant; it contributes to the timely discovery of potential faults and their immediate restitution.

Schletter is the largest manufacturer of support bases for photovoltaic panels in the world. The difference with Schletter is that geographic positioning data are collected and the static load in each area is computed using Schletter’s database. Wind data and snow depth are taken into account for this calculation, and the support base is reinforced accordingly so as to fulfil the requirements of the 2005 euro-code.

Apart from the classic support bases in reinforced concrete, Schletter has developed the pole planting technique. This technique allows for rapid installation and easy rehabilitation of land to its former state when photovoltaic plants are decommissioned.

With this technique, poles are planted on a trial basis in order to ascertain whether the plot of land is suitable or not.

Aluminium profiles and poles are made with thermal galvanized steel at a factory near Munich.

The pole planting operation, assembly of bases and installation of photovoltaic panels is carried out by specialized staff (German technicians). Perfection is thus achieved with respect to the final result.

Apart from that, in cooperation with SOLON SE, our company has developed a new method for installing photovoltaic panels. According to this method, on the back side of the photovoltaic panels, 6mm2 stainless steel screws are screwed into support holes available on the aluminium profile of photovoltaic panels; these screws are used as stays (i.e. there is a total of 6 support points as compared to the 4 offered by competitors). The fasteners are not screwed very tightly (using a dynamo wrench); just enough to avoid lifting of the photovoltaic panels by the wind. In contrast to competitors, this method protects photovoltaic panels given that, due to the fact that they are obliged to tighten the fasteners strongly for support, at those points the panels are subjected to stressing and there is a high probability of the glass cracking (at the points of the fasteners) due to contraction/expansion, and finally braking.

Special wire routing canals made with aluminium are ordered from Schletter and the wires along the support bases are threaded through these canals.

Finally, Schletter has launched a product that is also custom-made. This product is a part made with stainless steel, which is placed between fasteners and photovoltaic panels. This steel notches the anodized aluminium profile of the photovoltaic panel and thus provides sufficient earthing for the panel. Our company uses this product in all projects.

The biaxial heliostat system is suitable for all types of units and guarantees an ideal inclination for photovoltaic units with respect to the sun. In this way, not only is direct sunlight converted into energy but it is also converted in an efficient way and diffused light into energy. Energy production can increase by up to 40% using SunFlex biaxial heliostat systems energy, compared to installations with a fixed northern orientation. SunFlex heliostat systems are suitable for all types of photovoltaic units.

With the help of wind sensors, solar units are driven to horizontal position when wind speed of 60km/h is detected and the panels are thus protected even at higher wind speeds. All metal parts of heliostat systems are thermal galvanized or have corrosion protection. For this reason, a 20-year corrosion guarantee is offered. SunFlex installations are delivered in the form of low-cost modules and can be mounted easily at the installation site without requiring special tools.

DIRECT CURRENT (DC): For direct current (DC), LAPP Cable certified cables 6 mm in diameter are used for each string.

ALTERNATING CURRENT (AC): For alternating current (ΑC), FG7OR cables are used in a protective spiral or Cu/PVC/XLPE/SWA/PVC cables with a similar cross-section, so as to achieve a drop in voltage below 1% (for all AC up to the PPC). Due to its metal sheath, the second type of cable offers both mechanical resistance to rodents and surge protection. In our case, the main concern is to ensure losses less than 1% for DC and less than 1% for AC. The choice of cable type is based on the specific needs of the installation. In many cases, a combination is used.

COMMUNICATION (RS485): Type Li2YCY cables with a suitable cross section and an external metal sheath are used for communication (RS485); these cables are certified for direct underground routing. Nevertheless, our company installs these cables in a protective spiral.

Earthing – Direct lightning protection

A 25 x 2 mm tin-plated copper plate is used around the tables, with loops per table. This plate continues to the PPC (Public Power Corporation) pillar and is then connected to the PPC triangle. The plate is also joined to the support bases with special stainless steel connectors. The plate-to-plate connection is performed with special aluminium-thermal welding. This particular procedure is applied ONLY by our company, and ensures that the plate will remain a single body forever. In addition, copper and especially tin-plated copper very rarely becomes oxidized.

Finally, with respect to the calculation of earthing and the lightning rod, a study is carried out which takes into consideration the quality of the soil and the frequency of lightning strikes in the area. An insulated collection system is used as protection against direct lightning strikes; this is the latest development in the field of lightning protection.

Thanks to this system, any lightning that strikes the rods is led directly to the soil. This prevents strong surges within the photovoltaic plant, and surge diverters become even more efficient. NOTE: If the soil has no acidic or oxidising agents, a heat galvanised steel plate made by the company DEHN can be used to reduce costs.

Our company is the only company that uses certified stainless steel electrical panels made by RITTAL. Our advantage is a clearly longer life-span and increased mechanical tolerance. The switches we use are made by the top company in the sector, ABB. All regulations, as well as the rules of art and science, are applied.
Finally, surge diverters made by the German companies DEHN or PROPSTER are used on the AC, DC, and RS485 circuits. They have indicators for the replacement of each cartridge, so as to permit partial rather than total replacement of the diverter.