Photovoltaic modules and components, due to the nature of their employment, must be designed to withstand the most diverse of environments. The large spectrum of climatic conditions and mechanical stresses that these components must weather merit the application of some standards by which they can be tested for durability, reliability and safety. TÜV Rheinland operates several ISO 17025-accredited laboratories worldwide for type approval testing of flat plate as well as concentrating PV modules, PV components and solar thermal systems. Test data, collected over the past 20 years, shows that there is still a rather high failure rate when it comes to testing of PV modules, and also that there are different failure mechanisms for crystalline and thin-film PV modules. This paper presents data from these tests and draws some conclusions regarding the need for future standards development.
In the few years since the PV cell and module manufacturing industry first hit the radar, the identities of the winners and losers in the race to supply equipment have started to emerge. While some companies can genuinely claim to have been involved in the solar industry for some time, the majority are relatively new on the scene. This is hardly surprising, as the explosive growth in demand spurred any company with matching competences into action. In fact, over 300 equipment companies have been attracted to the industry since 2003 by the prospect of a share in a market valued at $4.4 billion in 2008. For the first time, a detailed analysis of the PV equipment suppliers has been compiled by VLSI Research. The Top 10 in this list are presented here and discussed in relation to their achievements in the industry and their outlook for 2009 and beyond.
A total of 2MWp of PV modules were sold on pvXchange’s spot market platform in December 2008. This corresponds to a sharp decrease of 60% when compared to the figures seen in the previous month (5.6MWp). Low trade volumes throughout the years are common on pvXchange; this year, bad weather conditions prevented many new installations, as did the current economic climate that saw many buyers waiting for further price decreases. The closing of long-term contracts has been postponed by many PV companies that are concerned that they will not find customers given the current circumstances. Again, First Solar’s CdTe thin-film modules were the most traded technology item on the pvXchange platform for the month of December.
Electricity has been around for a long time and no doubt will be for the foreseeable future, but it is quickly changing its nature. Owing to evolutions in power electronics, sustainable electricity generation and consumption came to the fore and now it is nigh on impossible for photovoltaics to operate without this technology. This holds true for efficient consumption such as plug-in electric and hybrid vehicles or compact efficient lighting. Power electronics need to be taken into account in relation to grids, for example in novel voltage-source HVDC connections. Photovoltaic energy conversion requires power electronics in order to adapt the floating DC-output to a fixed DC-level and typically further to a grid-compatible AC electricity. These converter (mainly inverter) technologies have evolved considerably over the past few years, in much the same way as has PV cell technology, but in a much less apparent fashion. It is, however, expected and required that the technologies will evolve even further to meet the demands of the future market and the electricity grid to which they will be connected. This article intends to give an overview of the challenges ahead for power electronics in photovoltaic energy conversion.
The PV industry has seen some incredible growth in the last five to eight years. This growth is essential in order to fulfill the challenging targets this industry has set itself to ensure it becomes an economical viable alternative energy source. A negative result of this growth, however, is the inefficient supply chain, where there is a lack of balance between demand and supply. The industry is going from one bottleneck to another. What is the impact of such inefficiencies on the supplier/manufacturer relationship? In this article, we collect information from short interviews of a number of fab managers in the wafer, cell and module domain, and try to answer this question.
Owing to the huge demand for photovoltaic products, the market is still very attractive for investments in production facilities. Nevertheless, the increasing number of competing photovoltaic manufacturers and the decrease in governmental subsidies require substantial and continuous cost reductions. Whilst existing facilities can save costs by enhancing cell efficiency, optimizing production processes or reducing material costs and other resources, for new manufacturing sites there is a great potential in making efficient use of economies of scale. This also holds true - to some extent – for expanding existing fabs. This paper presents the logistics behind and the benefits of implementing economy of scale in a PV manufacturing facility.
Materials innovation in solar photovoltaic manufacturing has long played a key role in efforts to raise cell and module conversion efficiencies, improve overall device performance and reliability, and lower the overall cost per manufactured watt. Research and development in areas such as ultrathin-silicon wafering and replacement films for thin-film PV transparent conductive oxides often garner much of the industry’s attention. But a wide range of emerging technologies could provide crystalline-silicon and thin-film cell and module manufacturers the kinds of materials solutions that will accelerate their attempts to reach competitive levelized cost of energy metrics and ultimately attain their goal of achieving grid parity with conventional energy sources – as well as open up lucrative market opportunities for the materials suppliers.
Laser-based tools have become increasingly visible within R&D labs, pilot production lines, and as the preferred technology used by many turnkey suppliers. As equipment types however, relatively little is known about the differences in the laser-based tools used for solar applications within each of the c-Si and thin-film segments. This paper explains the key components of a laser-based tool, and how they are adapting to meet the demands from next-generation production line equipment required by the solar industry.
Transparent conducting oxides (TCOs) are a special class of materials that can simultaneously be both optically transparent and electrically conducting and, as such, are a critical component in most thin-film photovoltaics. TCOs are generally based on a limited class of metal oxide semiconductors such In2O3, ZnO and SnO2, which are transparent due to their large band gap energy and can also tolerate very high electronic doping concentrations to yield conductivities of 1000S/cm or higher. However, these thee basic TCOs alone do not meet the TCO performance needs of emerging PV and other applications.
The rapid expansion of high volume manufacturing to meet growing demand in recent years has highlighted the development of increasingly higher throughput machines, especially in the critical bottleneck process of module assembly, specifically characterised by tabbing and stringing steps. Significant productivity improvements have come about with the development of integrated, highly-automated tabber and stringers from a range of equipment vendors. However, module assembly remains the most expensive step in conventional c-Si cell production. Equipment suppliers are also challenged to meet the evolving demands of processing thinner wafers and to address overall production cost reduction strategies while meeting yield/throughput goals that are seen as a significant enabler of reducing the cost per watt.
