• Energy Research
• engineering and technology close
• DE close
• EU close
• CN close
• CA close
• English close

The requirements for the contact metal deposited on solar cells are rising as the size of solar cells grows. Particularly, the improvement of the electric properties – especially the conductivity – is attracting interest. Light-induced plating is deemed to be a sophisticated approach to deposit a highly conductive metal layer on an arbitrarily generated seed layer. Although already in industrial operation to some extent, the mechanism is not understood in detail. In addition, the aim of avoidance of cyanide containing electrolytes for silver deposition is high. We will show voltammetric techniques are an appropriate approach investigating these topics. 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 1785-1788

Cryptographic primitives with low-latency performance have gained momentum lately due to an increased demand for real-time applications. Block ciphers such as PRINCE enable data encryption (resp. decryption) within a single clock cycle at a moderately high operating frequency when implemented in a fully-unrolled fashion. Unsurprisingly, many typical environments for unrolled ciphers require protection against physical adversaries as well. Yet, recent works suggest that most common SCA countermeasures are hard to apply to low-latency circuits. Hardware masking, for example, requires register stages to offer resistance, thus adding delay and defeating the purpose of unrolling. On another note, it has been indicated that unrolled primitives without any additional means of protection offer an intrinsic resistance to SCA attacks due to their parallelism, asynchronicity and speed of execution. In this work, we take a closer look at the physical security properties provided by unrolled cryptographic IC implementations. We are able to confirm that the nature of unrolling indeed bears the potential to decrease the susceptibility of cipher implementations significantly when reset methods are applied. With respect to certain adversarial models, e.g., ciphertext-only access, an amazingly high level of protection can be achieved. While this seems to be a great result for cryptographic hardware engineers, there is an attack vector hidden in plain sight which still threatens the security of unrolled implementations remarkably – namely the static power consumption of CMOS-based circuits. We point out that essentially all reasons which make it hard to extract meaningful information from the dynamic behavior of unrolled primitives are not an issue when exploiting the static currents for key recovery. Our evaluation is based on real-silicon measurements of an unrolled PRINCE core in a custom 40nm ASIC. The presented results serve as a neat educational case study to demonstrate the broad differences between dynamic and static power information leakage in the light of technological advancement. IACR Transactions on Cryptographic Hardware and Embedded Systems, Volume 2020, Issue 4

Technical Report (2012). doi:10.3204/XFEL.EU/TR-2012-002

To minimize shading when interconnecting single solar cells to solar modules the shingling technique can be used. Having an electrically conductive substrate this interconnection technique can be applied without any modification of the single solar cells itself. In case of electrically isolating substrates a contacting of the back metal electrode from the backside is in general not possible without modification of the substrate. Within this paper we present a possibility to interconnect flexible CIGS thin film solar cells on polyimide substrate using the shingling technique. To expose the molybdenum layer from the backside the polyimide substrate has been removed locally with a pulsed Excimer laser (248 nm wavelength, 20 ns pulse duration). To interconnect the exposed back contact with the front contact of the next solar cell the blind vias can be filled with a conductive adhesive. The surface of the exposed back contact of the CIGS solar cells has been characterized using optical microscope and SEM to acquire information on the completeness of the polymer etching and possible damages of the thin films. To characterize the exposed thin films electrically conductive-AFM images were made. First solar cells have been contacted from backside and electrically characterized. 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 3414-3417

Photovoltaic (PV) is one of the fastest growing electricity generation technologies in the world. Average annual growth rates of global PV-installations have reached around 45% for the last 15 years, which triggered a fast and ongoing reduction of production cost in PV industry. The presented work aims at consolidating historical price and cost information, deriving refined learning curves for PV modules and systems, and analysing the main factors of learning. For c-Si modules a valid learning rate of 17% is found based on a meta-analysis of various studies. In early years, even a learning rate of 30% is observed. As an example for thin-film PV, CdTe module cost reduce by 16% as the cumulated production output doubles. Interestingly, efficiency improvements contribute only in second order to the overall cost reduction for both technologies, emphasising the relevance of production excellence and economies of scale. On PV system level, a cost reduction of 14% per doubling of cumulated installed capacity is derived. Finally, a sensitivity analysis reveals that learning rate variations are only of minor influence on the overall global PV market potential. 26th European Photovoltaic Solar Energy Conference and Exhibition; 4697-4702

This paper evaluates various aspects of flexibility in power systems worldwide within the multi-country study framework of IEA Wind Task 25, including grid components and actions which have been favoured for enhancing flexibility in different areas/countries/regions, and how TSOs/ISOs/ utilities intend to manage variable generation in their operating strategies. One methodology to evaluate the diversity of flexibility sources is a "flexibility chart”, which can illustrate several flexibility parameters (e.g. hydro, CCGT, CHP, interconnection) in a polygonal radar (spider) chart.

In recent years, in order to promote the independent development of the new energy vehicle industry, Chinese government has decided to reduce the consumption subsidies for new energy vehicles until the subsidies are completely withdrawn. The reduction of consumption subsidy has a great impact on the production and sales of new energy vehicles in the whole vehicle market. However, does the reduction of this subsidy also have an impact on other enterprises in the new energy vehicles industry chain? This paper tests this problem using data from 2016 to 2018, and finds, through empirical analysis, that during the period of subsidy decline, the profitability of component enterprises is significantly positively correlated with this subsidies, while the r&d investment of enterprises is significantly negatively correlated with this subsidies. The results show that in terms of profitability, the reduction of consumer subsidies not only has an impact on the whole vehicle industry of new energy vehicles, but also has an adverse impact on the core component companies in the industrial chain. However, in terms of r&d, the reduction of subsidies has more negatively strengthened the input and attention of R&D in component companies.

Nowadays, much attention is payed to the development of renewable energy resources. Wind energy plays a major role in this issue. That is why there is a growing interest for improving the design process of wind turbines at many aspects. This study compares two types of offshore wind turbines structures, the monopile and the jacket structure, in their dependency on wave load characteristics’ variations. The examined wave characteristics are significant wave height and wave peak period. The jacket structure showed lower influence of increase of wave height to stresses in the cross section at the bottom of the structure compared to the monopile structure. The monopile structure showed slight dependency of stresses on increasing wave frequency, while the jacket structure showed nearly no dependency, due to its more complex geometry and higher stiffness.

We have attained superior quality a-SiGe:H and nc-Si:H materials deposited at high rate, ~0.6 nm/s for a-SiGe:H and 1-1.5 nm/s for nc-Si:H, and achieved improved multi-junction solar cell performance. For a-SiGe:H based cells, we have focused our effort on further improving the a-SiGe:H film quality by carefully optimizing process parameters, particularly with Ge content and profile, hydrogen dilution, deposition pressure and substrate-tocathode distance, to fabricate a-SiGe:H films with low defect density and good stability. For nc-Si:H based solar cells, we have mainly worked on improving the spatial uniformity and homogeneous properties for nc-Si:H deposition, and on optimizing the plasma process and selecting species to deposit further improved nc-Si:H. We attained 10.1% and 11.2% stabilized efficiencies, respectively, for large-area (≥400 cm2) encapsulated a-Si:H/a-SiGe:H/a-SiGe:H and a- Si:H/nc-Si:H/nc-Si:H triple-junction cells. Comparison between a-SiGe:H and nc-Si:H based technologies and future improvement will be presented. 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 2783-2787