Photovoltaics International Papers

This paper, the second in a series covering cost of ownership studies for photovoltaics [1], examines the need for saw damage removal and the follow-on processes of precleaning, texturization, and cleaning. The process considerations for wet and plasma approaches are further discussed before taking a detailed look at texturization using random pyramid formation. The paper will conclude with a view of current and future wet process techniques and a cost of ownership case study using Akrion Systems’ GAMA-Solar as an example.

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.

The current feed-in tariff (FiT) scheme in Italy has so far resulted in a total installed PV capacity just above 600MWp. The majority of those installations (77%) are building-adapted (BAPV) or building-integrated (BIPV) thanks to the higher incentives provided compared to non-integrated ground-mounted plants. Moreover, there are special premiums on top of the basic FiT, such as when asbestos roofings are replaced with PV modules. On the one hand, this makes the Italian PV market very attractive for those players specialized in roof applications, while on the other, it represents an opportunity and a strong motivation for both the installers and the manufacturers to explore innovative and standardized BIPV solutions and materials. Will this trend continue in the years to come?

With growth in 2009 suffering from recession and an ongoing credit crunch, this paper presents a review of the key trends in cell and module manufacture for the crystalline silicon (c-Si) PV module market. The c-Si segment remains the largest segment, and is competing effectively with less mature thin-film technologies. PV is still a largely uneconomic way to generate power, and requires subsidy to maintain sales volume and growth. While subsidies exist, the industry treads the narrow path of growing at a healthy clip, developing robust technology and business models, and mapping paths to profitable business without subsidies once PV installations become economically viable.

The uttermost importance of the regulation framework to trigger the development of a PV market has been recognized these last years in many European countries. For policymakers today one of the key questions is making the best choice to initiate and stimulate PV markets. In the aftermath of the financial crisis, EPIA has launched the PV Observatory initiative. It aims at analyzing the current state of regulatory frameworks in a set of countries, starting with the main European PV markets.

Development of fine-line crystalline silicon solar cells is a potential direction for application of high-efficiency and low-cost solar cells in the industry. Fine-line mask-free metallization offers huge potential to increase cell efficiency by reducing metal shadowing losses and surface recombination losses. At China Sunergy, three promising approaches for fine-line crystalline silicon solar cells are currently undergoing research, including processes such as laser doping selective emitter (LDSE) technology, inkjet or aerosol jet printing of metal paste and upgraded screen-printing technology. This paper presents the basic investigations of these three manufacturing technologies, singling out the technology that presents the most potential for further application.

An improved understanding of multicrystalline wafer quality can explain variations in cell performance across multicrystalline silicon blocks. Infrared scanning can detect precipitates in a silicon block, while photoluminescence combined with defect etching can reveal needle-like precipitates along the grain boundaries. Such precipitates typically lead to reduced shunt resistance. Crystallographic defects that lower the current collection and the final cell efficiency can also be identified. Understanding the influence of these defects is important for the development of a crystallisation technology that results in a substantially better cell efficiency. The use of the improved material quality in an innovative cell and module technology have led to the world record module efficiency of 17%. This paper will illustrate one example of how an improved understanding of multicrystalline wafer quality can explain the variations in cell performance.

It is widely acknowledged that, without government subsidies, solar power still cannot compete effectively with conventional sources of electrical energy. As the industry strives to make solar electricity affordable and as a viable alternative to fossil fuels, solar power technology companies are diligently moving towards reducing the manufacturing cost for solar modules. In the case of thin-film solar cells in particular, as a benchmark, the cost of for solar power must be reduced for it to be competitive or to attain grid parity. This paper presents a number of opinions from industry leaders on how best to decrease this vital cost.

The PV industry is expected to eventually reduce its manufacturing costs well below €1/Wp. Major technological changes lie ahead of us for manufacturing wafers, solar cells and modules if this cost target is to be met. In order to focus R&D efforts amongst the myriad options, and to speed up the learning curve, the PV industry (equipment vendors, material suppliers and PV manufacturers) may benefit from collaborative efforts guided by an ITRS-like roadmap. In this paper we present the IMEC roadmap, the target of which is to reduce drastically the amount of pure Si needed per Wp by combining efficiencies beyond 20% with aggressive reductions in wafer thicknesses.

In today’s market, crystalline silicon wafer technology dominates industrial solar cell production. Common devices feature opposing electrodes that are situated at the front and rear surface of the wafer and subsequent front-to-rear interconnection is used for module assembly. This paper reflects the functions which have to be fulfilled for the back-side contact of the solar cell as well as challenges and advances for the two basic classes: full-area and local rear contact formation. While full-area contacting has proven to be a reliable technology for industrial production, local contacting through dielectric layers has yet to be put through its paces in industrial implementation.