PV Tech Power Papers

Meeting the exact delivery schedule of large-scale power plants is crucial for fulfilling customer expectations and contract specifications. Mauoro di Fiore and Maren Orgus of Hanwha Q CELLS discuss how to overcome specific local challenges to deliver large-scale power plants on time and on budget.

Emanuele Tacchino outlines the lessons learned from the major solar secondary markets for helping investors utilise due diligence expertise to hedge risk and increase the long-term profitability of their asset acquisitions.

Plant control | SCADA technology enables PV plant owners to maintain their portfolios more efficiently and respond to increasingly stringent requirements from grid operators, yet avoid information overload. Sara Ver-Bruggen looks at the state of the art in SCADA systems as PV systems and fleets grow in size.

Grid investment | An ambitious plan is being drawn up to overhaul New York’s electric grid infrastructure, an exercise that some have priced at US$30 billion. Andy Colthorpe looks at the efforts underway to ensure renewables and energy storage are a central part of bringing the state’s power system into the modern age.

Operations and maintenance | The distribution and growing size of PV fleets mean new approaches to plant operation and maintenance are needed. Florian Danner, Jens Kahnert and Bjarn Röse of Conergy Services outline the key ingredients for cost-effective O&M in a globalised industry.

On-site testing | PV project owners are becoming increasingly conscious of the need to understand how their plants are performing in the field. Ben Willis explores how mobile testing units are emerging as an important tool in the early detection of faulty module equipment.

Defect assessment | DuPont Photovoltaic Solutions recently completed a five-year study of commercial crystalline silicon PV systems, amassing a wealth of new information about PV system field experience and PV module defects. Principal investigator Alexander Bradley discusses the findings, which, in addition to supporting the company’s ongoing analysis of materials performance, are expected to provide benefits across the industry. Building on the industry knowledge pool contributes towards the standardisation of performance expectations across the solar industry, enables the development of more stringent risk mitigation techniques, and helps purchasers of solar power systems make educated and informed materials assessments.

Power loss | The highly accurate module efficiency certified by accredited laboratories right after module production is at odds with the very rough estimate of the module’s long-term efficiency stated by the manufacturer for its expected lifetime, through a commonly accepted and industry-standard power warranty. Agustin Carretero of skytron energy presents an innovative method for calculating module degradation by using string-monitoring systems, and compares the results obtained for a case study with the module manufacturer’s power warranty statement.

Module performance | The potential for PV modules to fail before the end of their intended service life increases the perceived risk, and therefore the cost, of funding PV installations. While current IEC and UL certification testing standards for PV modules have helped to reduce the risk of early field (infant mortality) failures, they are by themselves insufficient for determining PV module service life. In this paper, teams from Fraunhofer CSE and Fraunhofer ISE present the results of the Fraunhofer PV Durability Initiative’s third round of testing, which now includes 10 module types.

Power oscillation | In the last few years the power rating of PV power plants has risen very quickly to values reaching several hundred megawatts. This means there are hundreds, or even thousands, of inverters operating in parallel in these plants. Furthermore, these large-scale PV power plants are often built far away from cities and are therefore connected to the grid via long transmission lines. This leads to weak grid conditions in the power plants, and these conditions give rise to the risk of electrical instabilities within the plant, or instabilities of the plant within the grid. Roland Singer of Fraunhofer ISE explains how these electrical instabilities can be detected and counteracted.