Photovoltaics International Papers

This article will look at what trends can be gleaned from patent application publication figures of the past decade in the sector of PV technology. The study looks at the number of patent applications in PV technology published worldwide between 1999 and 2008. The data will show in which regions and countries patent protection is being sought. The figures are taken from patent documentation databases developed by the European Patent Office (EPO) and Japan Patent Office or databases used worldwide and available at the EPO, and they are retrieved mostly using patent classification schemes. The article also provides a brief overview of the role of the EPO and what companies, researchers and individual inventors should keep in mind when applying for a European patent.

Laser doping is discussed often in relation to silicon photovoltaic cell efficiency enhancement. However, the specific use of lasers for dopant diffusion falls within a broader category of ‘Laser-Assisted Selective Emitters’. Understanding the benefits enabled by laser tools here is important not just in explaining what laser doping is, but why laser processing features in most selective emitter concepts.

With the ever-growing challenge of remaining financially viable in today’s economic climate, some companies in the PV industry are adapting and applying the structures and principals of project finance to the photovoltaic assets. The purpose of project finance is to create a business structure which brings together multiple entities, aligns their interests, and allocates the project’s inputs and outputs (i.e. risks and rewards) in such a way that the overall benefits derived from the project are maximized.

The process of wafering silicon bricks into wafers represents about 20% of the entire production cost of crystalline silicon solar cells. In this paper, the basic principles and challenges of the wafering process are discussed. The multi-wire sawing technique used to manufacture wafers for crystalline silicon solar cells, with the reduction of kerf loss currently representing about 50% of the silicon, presents a major challenge for further research efforts. Another relevant field of research is the reduction of wafer thickness in order to obtain more wafers per millimetre of brick length. The last subject that is addressed in this paper is the general optimization of the wafer surface and geometry, as the multi-wire saw cutting process influences the mechanical properties of the wafers and can have further effects on subsequent process steps.

Solar photovoltaic power plants have emerged in recent years as a viable means of large-scale renewable energy power generation. A critical question facing these PV plants at the utility scale remains the competitiveness of their energy generation cost with that of other sources. The relative cost of electricity from a generating source can be compared through the commonly used levelized cost of electricity (LCOE) calculation. The LCOE equation evaluates the life-cycle energy cost and production of a power plant, allowing alternative technologies - with different scales of operation, investment, or operating time periods - to be compared. This article reviews the LCOE drivers for a PV power plant and the impact of a plant’s capacity factor on the system LCOE, as well as the effects of various factors such as capacity and geographical location. The economic tradeoffs between fixed and tracking systems are evaluated as well as a review of land use, plant operation and maintenance costs.

New interconnections requirements for utility-connected photovoltaic systems are coming into play in several European countries, armed with the task of supporting the grid operation and stability. This approach to better integration of photovoltaic systems into the electric power system enables a larger selection of renewable energies. This paper presents the new grid code in Germany as an example of this improved integration, complemented by a brief report regarding activities currently being undertaken to ensure European harmonisation of interconnection requirements.

Although simple in concept, a photovoltaic solar cell is a difficult feat of technology in execution. The challenge of balancing cell structure design, material optimization and module technology to achieve efficient, low-cost modules that perform in aggressive environments for up to a generation is huge. The modules’ structure has to support and protect a thin, fragile slice of semiconductor, while ensuring a stable environment free from contamination and moisture with little or no change in the incident light on the cell. Key to the modules’ performance are the first-level polymeric materials that contact the cell and conductor structures, hold the module together, and in many cases form the second-level protection of the cells from the environment. In this article we explore the industry dynamics in the supply of advanced materials for module assembly, the new technology directions, and how the market will develop over the next five years.

The current industry situation of more competitive business approaches, increased PV project sizes and investments but declining profit margins renders an accurate knowledge of PV performance a vital factor in remaining competitive. Comprehension of expected lifetime and energy yield of PV generators is essential. Therefore, accurate characterization of PV modules is quickly becoming a more and more significant issue. This article gives an overview of the characterization topics of PV modules in terms of safety, failure susceptibility, overall reliability, system performance and energy rating.

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 these stock levels at short notice, thus creating a spot market. Spot markets serve the short-term trade of 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.

Over the past few decades, the PV equipment manufacturing market has seen a significant change in technologies. Cell sizes are being increased, while cell thickness has decreased at an ever-increasing speed of technological innovation, from 4” 340µm cells in the 1990s to 6”+ 180µm being the current industry standard. Thin-film modules pose completely new challenges to module manufacturing technology with a strong integration of the manufacturing of the active layers into the module production flow. This articles analyses the pros and cons of an increased level of line integration from the viewpoint of an established PV module producer.