Photovoltaics International Volume 31

Capital expenditure by the solar PV industry continues to rebound from the lows of 2012, but the spending trends have now shifted from polysilicon expansions to cell capacity additions. In particular, the transition to cell capex has been driven mainly by the need for Chinese module suppliers to diversify manufacturing outside mainland China and especially to countries in Southeast Asia, coupled with the ongoing problems for polysilicon producers struggling to adapt to sales prices for goods produced.

Double-glass PV modules are emerging as a technology which can deliver excellent performance and excellent durability at a competitive cost. In this paper a glass–glass module technology that uses liquid silicone encapsulation is described. The combination of the glass–glass structure and silicone is shown to lead to exceptional durability. The concept enables safe module operation at a system voltage of 1,500V, as well as innovative, low-cost module mounting through pad bonding.

We are always hearing about champion cells demonstrating efficiencies of 24% or higher, yet only 20 or 21% can be obtained at the module level. This paper highlights the different loss mechanisms in a module, and how they can be quantified. Once it is known where photons and electrons are lost, it is possible to develop strategies to avoid this happening.

Investors require a guarantee of a minimum lifetime for PV installations. It is tempting to provide such a guarantee for a longer lifetime simply by specifying test conditions that are more and more severe. In this paper it is argued that, with a more detailed understanding of the basic mechanisms determining cell material behaviour under specific exposure conditions, not only can the inherent lifetime of solar cells and modules be improved, but also the predictive value and effectiveness of lifetime testing. An overview of the literature contributions regarding the influence of damp-heat exposure of the layers in Cu(In,Ga)Se2 (CIGS) solar cells is presented.

The c-Si PV industry has been historically dominated by the conventional full Al-BSF cell architecture, applied to p-type silicon, because it has so far always yielded the lowest cost at the module level (€/Wp). At the system level (€/kWh), on the other hand, bifacial PV and related reference bifacial n-PERT technology seems to be a better option for cost reduction, but additional cell processing steps (and related costs) are inhibiting bifacial PV growth. This paper first introduces INES’ reference 20%-PERT technology ‘SOLENN’, which is based on a conventional gaseous diffusion process. Passivating/anti-reflective/doping SiOxNy:B and SiNx:P layers have been developed at INES, and the properties of these multifunctional layers are described in detail. By then capitalizing on the passivating and optical properties of the multifunctional layers, INES’ so-called ‘SOLENNA(3)’ technology is presented. Finally, the cost calculation based on a 100MW line capacity and on a comparison of SOLENNA(3) with reference technologies (such as Al-BSF, PERC and BBr3 PERT) was completed, without considering the potential gain from the bifacial properties.

This paper introduces and explains a simulation-assisted approach for determining and ranking the most influential causes of variations in experimentally obtained solar cell efficiencies, using the example of an industrially feasible multicrystalline silicon (mc-Si) passivated emitter and rear cell (PERC) process. The approach presented is especially helpful for ramping up PERC production; however, since it is basically transferable to any solar cell concept, it can also be applied to optimize established production lines.

The purpose of this paper is to determine how increased c-Si PV module production might affect future silver demand and prices, as well as the impacts on total c-Si module manufacturing costs. To evaluate how PV’s changing demand for silver might affect future silver prices, and the impact in terms of manufacturing costs, some scenarios of silver’s contribution to c-Si PV cell manufacturing costs are compiled on the basis of projected changes in demand and price as a result of changes in material intensity. The analysis indicates that an expansion of c-Si production from 55GW/year to 250GW/year results in a 0.05–0.7￠/W increase in manufacturing costs because of higher silver prices.

Because the wire itself is the dominant cost in diamond wire sawing, economics dictate that the wire life must be prolonged. This paper presents recent progress made in real-time non-contact monitoring of diamond wire using the resonant vibration (RV) characteristics of the wire. Additionally, a theoretical framework is presented which shows that the characteristics of the resonance curve do not change at speeds above 500m/s. As a result, this technology is expected to be able to meet the increasing demands of monitoring diamond wire wear during sawing as the wire speed continues to increase in the coming years.

During the severe plummet of PV prices that took place during 2008–2012 as a result of overcapacity, the polysilicon sector suffered a major adjustment of costs and capacity to face the reduction in prices and the mismatch between demand and supply. In 2012 that significant drop in prices provoked the bankruptcy of many polysilicon producers, with only the large and efficient players still surviving. However, there was also an impact on the (at that time) promising and immature industry of metallurgical purification of metal silicon, also known as upgraded metallurgical-grade silicon (UMG-Si). The strong selling point of UMG-Si producers – the production costs – was no longer an asset, leaving UMG-Si with nothing but its weakness – the quality. The generation costs for solar energy are currently comparable to those for conventional fuels. The solar industry is self-sustaining and is not dependent on government subsidies. In this current situation, the industry requires an updated comparison between the two main routes of silicon purification and their products, which is the aim of this paper.

The production toolset is not the only significant source of power consumption in PV cell production. Cooling water, climatization, pressurized air and, in some cases, clean-room conditions drive up the electrical energy demand, while geographical location also has an influence. The extent of this additional consumption over and above the toolset is demonstrated by a number of quantitative examples in this paper.

In this quarterly report a full analysis is given for the first time of two years’ worth (2014-15) of PV manufacturers’ capacity expansion announcements as well as an assessment of announcements that have or are planned to convert to effective new nameplate capacity through to the end of 2016. The analysis provides the first insight into new capacity ramp profiles of effective capacity expansions over the last two-year period and highlights future ramp profiles expected through to the end of 2016.