Technical Papers

Solar enterprises will each be faced with the occasional surplus or lack of solar modules in their lifetimes. In these instances, it is useful to adjust stock levels for modules at short notice, thus creating a spot market. Spot markets serve the short-term trade in different products, where the seller is able to permanently or temporarily offset surplus, while buyers are able to access attractive offers on surplus stocks and supplement existing supply arrangements as a last resort.

Traditional markets for PV will be scaling back on the level of demand for PV, but there are already signs that the developing countries will be stepping in to pick up the slack. This will be a combination of both standard grid-connected and micro-grid types of installation. Micro-grids present the opportunity for countries to develop a cellphone type of model for power distribution whereby regions without electrification can have a regional power source that allows for local access. This market is projected to become significant in the next several years, as the access to lower cost PV makes this option more easily implemented. This paper evaluates the market size of what has been an overlooked ‘niche’ for PV and describes the key considerations for a micro-grid installation, the developing conditions favouring installation, and some of the specifics of a micro-grid case study. The point is made that the grid-connected market will be increasingly assisted by the micro-grid segment as the latter becomes a significant source of PV demand and energy provision. Contrary to common notions, the micro-grid and hybrid off-grid segments will play an increasing role, even in areas with a grid in place.

t is well known that the cost of silicon materials is the major cost factor in crystalline silicon PV module production. Polysilicon price accounts for about 30% of total module production costs. While the PV industry has set a polysilicon price target of US$40/kg by 2015, this goal will not be reached if demand continues to exceed supply and if new plants cannot reduce operating costs below US$25/kg. Given a continued 30% annual growth in demand for PV modules, new polysilicon plants and expansions are needed to avoid shortages of high-purity, cost-effective polysilicon. This paper discusses the major factors in polysilicon production costs, the important elements of polysilicon plant design for reducing operating costs, the key cost elements of polysilicon plant operations, and how the design of polysilicon products can reduce crystal growth costs.

Various economic and political influences continue to push high-volume manufacturing of semiconductor and PV devices into relatively arid and water-constrained geographies. As the social, economic and political focus on water resources and sustainability increases daily, the need to address the supply, use and disposal of water at manufacturing facilities is growing increasingly more complex. Historically, PV manufacturing has not been considered a major water consumer so there has been little scrutiny of water management. As the costs of water and wastewater disposal spiral upwards, water resource management becomes a significantly more important factor in the capital and operating costs of PV manufacturing. This paper outlines the preparation of a water management diagram (WMD) with reference to the development of water systems for new PV manufacturing plants, and discusses some cautionary design considerations.

There are still a lot of “ifs” when it comes to concentrator photovoltaics, but it’s starting to look like the question of “when” the technology will start to gain serious market traction may be sooner than some think. With tens of megawatts of projects either recently finished, under construction, or in the last phases of project development — and hundreds more MWs in the longerterm pipeline — deployment of the highefficiency systems may reach triple digits by the end of 2011 or beginning of 2012. On the technology front, as many as a half-dozen cell companies are bringing 40%-efficient cells to market this year, which will help to further reduce CPV’s increasingly compelling levelized cost of energy.

Liyou Yang started in the thin-film game in 1985 with BP Solar, where he eventually ran the company’s amorphous-silicon research efforts. “Once you get into it,” he smiled, “you get hooked.” During the course of our conversation at Astronergy’s headquarters, the Rutgers-educated president/CEO would often reference his time at the old company, using his early experiences as reminders of just how far the technology and the solar industry in general have come since those pioneering days in the 1980s and ‘90s.

Phosphorus dopant pastes are an attractive alternative to the conventional phosphorus oxychloride (POCl3) dopant source for emitter processing in solar cells, as they allow the fabrication of selective emitters on an industrial scale. In this paper it is demonstrated that single-sided uniform screen-printed emitters, processed with phosphorus dopant pastes, can getter multicrystalline silicon (mc-Si) wafers more effectively than conventional double-sided uniform POCl3 emitters. This result is confirmed by minority carrier lifetime measurements with the quasi-stead-state photoconductance (QSSPC) method. Solar cells with selective emitters were processed using phosphorus dopant pastes on mc-Si wafers and were subsequently characterized. The current-voltage (I-V) results are improved compared to uniform POCl3 emitter solar cells and an increased internal quantum efficiency (IQE) for selective emitter solar cells is demonstrated.

Technology computer-aided design (TCAD) is pervasive throughout research, development and manufacturing in the semiconductor industry. It allows very low-cost evaluation of process options and competing technologies, guides process development and transfer to production and supports more efficient process improvement with minimal down time in the factory environment. This paper reviews the use of TCAD in the semiconductor industry and shows, with some illustrative examples, its important enabling role for the PV industry.

Exceptional demand characterized the PV industry in 2010. Uncertainty regarding incentive schemes in a number of key markets drove global installations, and inverter shipments grew by over 160% as investors and developers rushed to complete projects, fearing that incentives would be reduced or removed altogether. IMS Research estimates that inverter shipments exceeded 20GW in 2010 and sales of small three-phase inverters, rated between 10-20kW, grew by around 200% in 2010. Inverters rated at over 500kW are estimated to have grown at a similar rate, but continue to represent a smaller share of revenues.

The behaviour of PV markets over the last decade in Europe has taught us that not only it is necessary to optimally design support schemes, but that priority access to the grid for renewable energy sources and the reduction of administrative barriers are the key market drivers for sustainable development and essential for the markets to sustainably develop in the long term. This paper provides an overview of Europe’s PV market performance and delivers policy recommendations by means of EPIA’s PV Observatory model.