Photovoltaics International Papers

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.

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.

News of credit crunch woes filtering down the lines over the past few months has instilled a sense of frugality in all industry sectors. While the credit crisis has indeed affected the PV industry, German banks, investors and creditors have claimed that the financing of small PV systems in the private sector seems not to be endangered. Downstream players are still optimistic, but the upstream sector is anticipating severe damage as a result of the economic situation. An interactive workshop-style discussion, hosted by the German market researcher EuPD Research and its consulting division 360Consult, invited top-level executives to contribute their experiences of the current financial situation, as discussed in this paper.

The U.S. residential solar market is poised for growth. For solar companies seeking to capitalize on the growth potential of this market, the keys to success will be sales volume and operating efficiency. Solar employee purchase programs (solar EPPs), which have been initiated by companies as diverse as SunPower, REC Solar, and SolarCity, represent a new and potentially important channel for increasing sales and improving sales efficiency. Driving these programs are increasing corporate sustainability initiatives and growth in voluntary employee benefit offerings, especially employee purchase programs and green benefits. This article provides an introduction to solar employee purchase programs, analysis of the business ecosystem, and discussion of an example program. It is based on the industry’s first report to identify and analyze this emerging trend, which was published by AltaTerra Research in November 2008 [1].

In any solar cell process, the metallization step is critical as it often sets conditions and limitations for the other process steps. The main metallization technique used today in Si solar cell production is screen-printing of metallic pastes, namely Ag pastes for the front side, Al pastes for most of the rear side, and Ag or Ag-Al pastes for the solder pads at the rear. While these techniques are clearly robust and convenient, they have limitations. Therefore alternatives are being investigated. A technique that is presently finding its way into production is two-step metallization with Ag plating. Another more radical approach is to avoid printing altogether, instead using some kind of ablation followed by plating. For the rear, the full Al-BSF is being replaced by dielectric passivation and local Al-alloyed contacts. Back-contacted cells are increasingly being introduced in production, and they pose very specific challenges to metallization. For the sustainability of Si photovoltaics, it is crucial that the future metallization solutions only make use of abundantly available and non-toxic materials.

This paper presents a detailed assessment of the value of photovoltaic energy within the German energy supply structure, taking into account the correlation between actual consumption and local power generation. Contrary to previous statistical approaches, this paper takes a new dynamic approach, modelling the dynamic behaviour of the PV power generation as a one-year time series. A comparison with the time series of the power demand allows assessment of the value of PV energy. The value of PV energy mainly results from its ability to substitute conventional power generation and the benefit of this kind of decentralized power generation for network stability and quality. An evaluation of these aspects is carried out for the year 2005 and a likely scenario in 2015.

Apart from some obstacles and bureaucratic hindrances, the Italian PV market has recently joined the upper echelons of the solar industry. Along with small and medium-sized systems, the commercial and large-scale segment in particular has a great deal of promise. Even though the local industry is still trying to block the domestic market from international competitors, increasing numbers of foreign investors are entering the market. In this close-up of the Italian PV market, the country’s participation in the solar energy industry is reviewed and a projection to 2010 is given, with particular emphasis on the country’s potential to be a major player in the large-scale installation sector.

Anyone familiar with the PV industry can attest to the remarkably accelerated pace of innovation aimed towards generating solar power more cost effectively relative to conventional means of producing electricity. Many of high-technology’s best minds are bringing expertise in materials, manufacturing process, and electronics to tackle the challenge. The resultant gains in cost effective manufacturing, silicon availability and greater irradiance conversion efficiency will make continuous and sustainable impact to cost per kW generated akin to the predicable improvements in transistors per mm2 which has fuelled the semiconductor industry for the past 25 years (although we are not yet so bold as to devise the PV version on Moore’s Law). As less than 0.01% of electricity generated comes from PV installations [1], demand will materialize and the need for public subsidies will decline as the economics improve. This paper will investigate the steps required to make every solar project a “perfect” project by putting forth parameters for evaluating solutions for the problem areas.

The use of perfluorinated gases such as NF3, CF4 or SF6 for PECVD (plasma enhanced chemical vapor deposition) chamber cleaning has a much higher impact on global warming than does the use of onsite-generated F2. This holds true even when supposing that in the future much more effort is paid for the correct abatement and a leak-free supply and take-back chain. This paper will discuss the steps available to the PV industry for control and reduction of carbon emissions in the chamber cleaning process.