This issue of Photovoltaics International focuses on the steady adoption of PERC as the technology of choice for providing a quick boost to cell performances. Our chief analyst, Finlay Colville, reports that PERC is a key driver for internal technology roadmaps of all silicon cell providers and is indirectly influencing the development of other technologies in competing n-type and thin-film segments. However, PERC is not without its drawbacks, and one of these is its increased susceptibility to light-induced degradation. Other highlights include ISC Konstanz on the future of back-contact technology and ECN on the development of a new technique for minimising recombination losses in silicon solar cells.
This issue of Photovoltaics International features an industry-first analysis of the rate at which manufacturing expansion announcements over the past two years are being turned into real nameplate production capacity. In another special report Finlay Colville characterises the nature of the current PV capex cycle as compared to the last. Whereas the previous spending cycle was notable for being “frantic”, the latest one has so far been more measured, with manufacturers focusing on strengthening their positions in specific segments of the value chain. Other highlights in this issue include a paper from researchers at the Solar Energy Research Institute of Singapore (SERIS) exploring cell-to-module losses.
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.
