Technical Papers

The output power of a solar module is the sum of the powers of all the individual cells in the module multiplied by the cell-to-module (CTM) power ratio. The CTM ratio is determined by interacting optical losses and gains as well as by electrical losses. Higher efficiency and output power at the module level can be achieved by using novel ideas in module technology. This paper reviews methods for reducing different optical and electrical loss mechanisms in PV modules and for increasing the optical gains in order to achieve higher CTM ratios. Various solutions for optimizing PV modules by means of simulations and experimental prototypes are recommended. Finally, it is shown that designing PV modules on the basis of standard test conditions (STC) alone is not adequate, and that, to achieve higher CTM ratios by improving the module designs in respect of environmental conditions, an energy yield analysis is essential.

In this quarterly report on global PV manufacturing capacity expansion announcements in the first quarter of 2016, key analysis is devoted to the continued high level of intensity, which is continuing to track significantly higher than in the prior-year periods of 2014 and 2015. The report will also provide insight into the specific capacity expansion plans of the largest PV manufacturers, known as the ‘Silicon Module Super League’ (SMSL).

The back-contact (BC) technology currently available on the market is considered to be either highly efficient but extremely expensive (interdigitated back contact – IBC – from SunPower) or, if cost-effective, not very efficient (metal wrap-through – MWT) compared with what is becoming today’s new standard: passivated emitter and rear contact (PERC) technology. Something in between, such as low-cost, high-efficiency IBC cells and modules, would therefore be desirable. This paper briefly describes the past, focuses on the present, and forecasts the possible future developments of BC technology in respect of efficiencies, costs and applications.

The passivated emitter and rear cell (PERC) process has been successfully transferred to mass production, with the market share of multicrystalline (mc) silicon being around 50%. This new technology can, however, lead to severe reliability issues despite the higher initial solar cell efficiencies. In particular, light-induced degradation (LID) of mc-PERC solar cells has been reported to cause efficiency losses of up to 10%rel. This highlights the importance of understanding different types of LID and of testing the stability of solar cells under actual operating conditions.

Through its Corporate Clean Energy Universe, market researcher Clean Edge is tracking the 37 US corporations leading the way on low-carbon and renewable energy adoption. Its managing director, Ron Pernick, tells Ben Willis of his hopes that a second wave of smaller companies will follow their lead as new green energy business models hit the mainstream.

Sandfire Resources, a mid-tier Australian mining company that operates the mine, called on developers to co-locate not only a solar power plant, but also a utility-scale energy storage system alongside its existing diesel power station. Showcasing the latest technological advances, the newly completed project in the Peak Hill Mineral Field has been hailed as one of the largest renewable energy systems installed at a mine anywhere in the world and certainly the largest in Australia.

Certifying the quality and performance of an entire PV array has been a notable development in the past two years. Sara ver Bruggen looks at the extent to which developers, investors and insurers are turning to plant-level certification to guarantee the design, construction quality and performance of a PV system.

The aim of the Solar Bankability project is to establish a common practice for professional risk assessment, which will serve to reduce the risks associated with investments in PV projects. In this article the project team discusses a key aspect of this work: the development of a methodology for the assessment of the economic impact of failures occurring during operation but which might have originated in previous phases.

After a series of hammer blows, and against the backdrop of Brexit uncertainty, the UK solar industry appears to have found some joy offering long-term contracts and self-consumption systems to commercial clients, a sector it had previously found hardest to crack, writes John Parnell.

Microinverters and power optimisers have become increasingly common features of smaller PV systems. Sara ver Bruggen reports on the technologies’ gradual transition into larger commercial and utility-scale applications.