Solarex Mart Nisan 2018

MAKALE
Quality requirements for high performance
at photovoltaic power systems in Turkey
Dr. Mete Çubukçu, Anıl Akanalçı
SolarMENA Energy and Env. Tech. Ltd.
info@solarmena.com.tr
Upon the identification of legal regulations, photovoltaic power systems (PVPS) based on solar energy have
been an attractive investment for any investors with small or large scale budgets in Turkey. Approximately 1.8
GWp PVPS was installed in 2017 and a growth which was greater than in any European country has been
experienced in the solar energy industry during the year. In this context, both technical component quality and
the financial return of the installed systems have gained great importance.
Correct performance of the PVPS planning, installation and operation stages will ensure technical and
economic reliability of the investments. Increase in competition in the market has expanded the product and
service alternatives. On the other hand, with reduced prices, changes have started to take place in the quality of
the products and the services.
Photovoltaic systems are a safe line of investment, but experience at the stage of practice has clearly shown us
the following so far: inspection of the engineering processes and component choices as well as the installation
process in compliance with standards by third party independent organisations, performance of tests prior to
commissioning and correct follow-up of performance during operation bear critical importance.
For a PVPS, technical risks may arise from the power plant components as well as from operational processes
during and after installation. In the previous years, photovoltaic modules were considered to be key components
in terms of acceptability for banks in case of power plants based on solar energy. However, remarkable reductions
have been experienced in the unit costs of photovoltaic modules in the present day. And this situation causes
focusing on the whole of the system besides the photovoltaic modules on the part of the lending institutions.
On the other hand, some components, for instance production costs of the photovoltaic modules of the
same technology do not remain fixed as the prices of the materials used at the production stage continuously
vary at different places of the world. This variable tendency compels the producers and customers in terms
of production and product quality. Further, such problems as PID (Potential Induced Degradation), micro
cracks, spiral traces, discolorations, etc. which may arise from dwelled upon recently reduce the investors’ belief
in longevity of the photovoltaic power plants.
In addition to photovoltaic modules, inverters are just like a bridge between the network and the power plant.
Network quality, as a whole, has so important a role in terms of reliability and acceptability for banks. Efficiency,
availability and repair and replacement costs of inverters may be the major factor in a system’s success or
failure in techno-economic terms. Even if an inverter proves to be successful at international standards, it may
discernibly lead to efficiency reductions when it is connected to an unsteady network infrastructure.
Performance ratio and unit electricity generation costs are the most important parameters in order to compare
the quality of large scale power plants. The performance ratio and unit electricity costs which the system may
have during the period of time in which it is planned to operate may be calculated in a manner which is closest
to reality on monthly or even daily basis.
Quality assurance for photovoltaic power plants
Thanks to modern technologies and inexpensive production costs, photovoltaic power plants with capacities
of GigaWatt may be installed. And this roughly means the provision of quality assurance of a complete system
possessing millions of modules, kilometres of construction, kilometres of cables, hundreds of inverters and
thousands of acres. In order to be able to obtain a high performance excellent system, power plant units with
standardised quality and perfect systems that have passed inspections in terms of both parts and design.
Performance measurement and calculation of a photovoltaic power plant is evaluated within the scope of
international IEC 61724 standard. Calculation of performance ratio by this standard is roughly made by taking
into account the irradiance falling on the surface at the module gradient angle and the alternative current
energy generated. The relevant standard enables us to take into account the losses while it also directly gives the
performance ratio of the system. Such losses may occur as a consequence of temperature-based losses which
cause or may cause nominal power reduction of the photovoltaic system, failure to use all of the incoming
©Fraunhofer ISE.
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March - April / 2018