As PV systems proliferate it is increasingly important to forecast their energy output in order to ensure a safe and reliable integration of their variable output into electric power grids. Dazhi young, André Nobre, Rupesh Baker and Thomas Reindl of SERIS outline a technique for generating large-scale 2D irradiance using data from pyranometers and plane of array cells.
Large-scale PV contractors must perform tests to verify the correct operation of a new installation. Jorge Coello and Leonardo Perez outline the minimum aspects to consider for the commissioning of large-scale PV plants using a methodology that has been successfully implemented in the commissioning of more than 40 PV facilities worldwide.
PV power plants require proportionally more up-front capital investment to develop and build than their fossil fuel counterparts. Modelling the lifetime performance of a PV power plant is therefore a critical exercise in proving a project’s bankability and securing finance to cover that cost. However, inaccuracies and uncertainties in modelling techniques create risk in the structuring of project finance. Evan Riley of Black & Veatch explores methods for improving the reliability of performance models and how then can be used to demonstrate that a PV facility will meet expectations.
Fixed and tracker solar mounting systems offer various relative cost and performance benefits. But as JA Solar’s Zhang Lan Jun and Gong Tie Yu describe, surprising results from field analysis of different systems used in China hold important lessons for developers wondering which ones to choose.
A next-generation PV plant architecture based on increasing direct current system voltage from 1,000VDC to 1,500VDC holds the promise of a more cost-effective and productive utility-scale plant due to lower installation and maintenance costs. Mahesh Morjaria, Kevin Collins and Michael Stavish of First Solar and Greg Ball of DNV-KEMA Renewables explore some of the challenges associated with the development of the technology and the efforts to address some of those challenges.
Modules based on p-type multi c-Si technologies look set to dominate the PV industry over the next five years, continuing a trend that has developed over the past two years. This paper explores why high-efficiency p-type multi seems destined to remain the workhorse of the global PV industry.
In anticipation of the expected increase in the use of back-contact cells in future PV modules, a number of different concepts have been proposed. This paper focuses on one approach that aims to stay close to conventional solder-based technology (tabbing - stringing) while still allowing the use of back-contact cells (which have more complex back-side metallization schemes). The advantages and disadvantages of such an approach are discussed, and the development of this technology is described in terms of process flow, materials, characterization and reliability.
With lower returns on investment in PV projects, financial institutions have an ever-increasing demand for risk mitigation. Project stakeholders are asked to provide evidence of risk-management actions and have to look for ways to guarantee an adequate level of quality for their systems. Product certification, although necessary to help qualify the design of a product, does not provide a guarantee that mass production will achieve the targeted quality level; it has therefore become necessary to find reliable methods to assess the quality of PV systems on a large scale. Production monitoring, as part of a global quality plan for a PV system, is a cost-effective way to implement real-time checks in the manufacturing facilities, providing reassurance for stakeholders and helping manufacturers to improve their manufacturing processes. This paper details the principles behind production monitoring, the methodology used and how to deploy a production-monitoring project.
With the objectives of reducing cell-to-module losses, improving module efficiency and reducing the price per watt, increasing importance is being placed on the optical properties of backsheets. It is assumed that a higher reflectance backsheet allows a better reuse of incident sunlight. However, this statement is not always true: another factor must be taken in account, namely the angular dependence of the reflected light. In this regard, backsheets with a high specular component deviate from the ideal Lambertian reflectance, resulting in a minor increase in module current. As a result, differences can be found in module power because of the use of backsheets with similar global reflectance but different angular components of reflected light. A total of 33 industrial backsheets with Tedlar, Kynar, EVA and PET layers from different suppliers were analysed. A comparison of backsheets with low and high global reflectances revealed that the power variation in a standard PV module reaches 0.54% abs. In the same vein, and for backsheets with similar global reflectances, it was experimentally found that the angular response of the reflected light was responsible for a power difference of 0.22% abs. in a standard module.
During the past two years remarkable performance improvements have been reported for polycrystalline Cu(In,Ga)Se2 (CIGS), CdTe and perovskite thin-film solar cells. In this paper the key breakthroughs in CIGS thin-film technology are reviewed and the scope for further performance improvements by analysing the stillremaining electrical and optical losses in record-efficiency CIGS solar cells is discussed. On the basis of this analysis it is believed that conversion efficiencies up to 25% are achievable with CIGS solar cells in the mid term. Furthermore, the potential for the concept of polycrystalline multi-junction solar cells to push efficiencies even further, towards 30%, is discussed. Finally, a short review of the CIGS market and an outlook from an industrial perspective are presented.
