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Multiple activities in the photovoltaic (PV) sector demonstrate a will to improve environmental impacts, reduce critical material uses and waste generated by linear supply chains. A common understanding of the remaining priority gaps in sustainability is, however, lacking, hindering the implementation of strategic courses of action. The United Nations Sustainable Development Goal 12 (SDG 12), targeting sustainable consumption and production, constitutes an entry point for PV stakeholders to examine their impacts holistically by reconciling ecological sustainability, criticality, and circularity. This article introduces a framework to map sustainability strategies in PV under the lens of SDG 12. A gap analysis is conducted to identify the current sustainability performances of PV value chains. The readiness level of the sector to close each gap is then evaluated, thus highlighting the ""low hanging fruits"" and the more consequent efforts required to achieve sustainability. Overall, a lack of common key performance indicators is noticed, resulting in a fragmented and uncertain sustainability landscape. A need for more coherence, sustainability leadership, and collaboration at the sectoral level is identified for all topics of SDG 12. In particular, the implementation of circularity strategies is linked to substantial technoeconomic hurdles, which need to be addressed.

Being a key technology in silicon solar cell production, the firing process conducted in infrared (IR) lamp powered conveyor belt furnaces is well established in the market. The purpose of the project FEUERDRACHE is to advance the classic firing process by raising throughput, energy efficiency and process control via increasing the process variability. To achieve the latter, an industry-oriented furnace is expanded by innovative features, which are thoroughly investigated: 1) faster belt velocity; 2) novel IR lamps; 3) thermography as an inline-capable alternative to thermocouple measurements 4) high-power laser as an alternative to a heated chamber.

The interest in cast mono silicon is increasing due to its lower energy consumption and resulting smaller carbon footprint, lower oxygen content and resulting less oxygen-related defects as well as easy scalability to large wafer formats like 210 × 210 mm2 full square. As a cast silicon alternative to high performance multicrystalline (hpm) silicon, which rapidly lost market share, we analyze the cell efficiency potential of cast mono silicon in a TOPCon cell structure. We show how the absence of grain boundaries and the exceptional tolerance of the material quality towards high temperature processing enable this significant increase of the cell efficiency potential compared to hpm silicon. The very effective suppression of crystal defects by the Seed Manipulation for ARtificially controlled defect Technique (SMART) results in a very low lateral variation of the high material quality. We present certified cell efficiencies of 23.3% on n-type material crystallized in our labs, which demonstrates the high efficiency potential even for our lab-type G2 crystallization. An additional crystallization experiment for 210 × 210 mm2 wafers demonstrates that SMART mono is compatible to large wafer sizes. A significant difference of the crystallization costs for Cz and cast mono crystallization as a function of electricity costs is discussed.

Intense pulsed light (IPL) is capable of entirely replacing thermal annealing (curing and contact formation) within back end processing of silicon heterojunction solar cells. In order to demonstrate this, full-size silicon heterojunction (SHJ) cells with IPL-processed screen-printed metal contacts are evaluated. Such cells reach conversion efficiencies of up to 23.0%. On average, IPL-annealed SHJ cells outperform their thermally treated pendants by 0.3-0.4% abs , in particular because of higher open-circuit voltages and fill factors. Moreover, IPL offers high throughput and low footprint. This results in a cost of ownership reduction potential of 6% rel compared to state-of-the-art thermal annealing.

Our novel metallization approach for silicon heterojunction (SHJ) solar cells takes advantage of a PVD metal-stack covered with a structured self-passivated Al layer as mask for electroplating a Cu grid. This plating metallization route enables a very low cost of ownership (COO) for SHJ solar cell back-end processing for busbars interconnection. Encouraging efficiencies of 22.1% are reached with FF > 81% and R s down to 0.39 Ω·cm2 on large area. A variation of the contact layer to ITO shows that of the investigated materials, TiW reached a sufficiently low contact resistivity down to 0.7 ± 0.3 mΩ·cm2 while for pure Ti it was too low to be measured (0.1 ± 0.3 mΩ-cm2). High busbar peel-off forces above 3 N/mm (Ti) are demonstrated.. Furthermore, a carefully adjusted etch-back procedure proves that AZO can be combined with our plated metallization to manufacture Ag- and In-free SHJ solar cells.

37th European Photovoltaic Solar Energy Conference and Exhibition; 242-251, Currently, PV industry is looking towards different technologically feasible options of transferring passivating contact or TOPCon cell concept from laboratory research towards industrial manufacturing. In this paper, we perform techno-economic assessment of industrial manufacturing of TOPCon-based solar cells after assessing various process routes based on currently production-ready and upcoming future alternative process technologies. Under given assumptions, TOPCon-concepts are found to remain economically competitive against bifacial PERC in terms of levelized cost of electricity (LCOE), if a minimum absolute gain in cell efficiency > 0.4- 0.6% can be maintained.

In patients undergoing general anaesthesia, intraoperative hypotension occurs frequently and is associated with adverse outcomes such as postoperative acute kidney failure, myocardial infarction or stroke. A history of chronic hypertension renders patients more susceptible to a decrease in blood pressure (BP) after induction of general anaesthesia. As a patient's BP is generally monitored intermittently via an upper arm cuff, there may be a delay in the detection of hypotension by the anaesthetist.The current study investigates whether the presence of continuous BP monitoring leads to improved BP stability.Randomised, controlled and single-centre study.A total of 160 orthopaedic patients undergoing general anaesthesia with a history of chronic hypertension.The patients were randomised to either a study group (n = 77) that received continuous non-invasive BP monitoring in addition to oscillometric intermittent monitoring, or a control group (n = 83) whose BP was monitored intermittently only. The interval for oscillometric measurements in both groups was set to 3 min. After induction of general anaesthesia, oscillometric BP values of the two groups were compared for the first hour of the procedure. Anaesthetists were blinded to the purpose of the study.BP stability and hypotensive events.There was no difference in baseline BP between the groups. After adjustment for multiple testing, mean arterial BP in the study group was significantly higher than in the control group at 12 and 15 min. Mean ± SD for study and control group, respectively were: 12 min, 102 ± 24 vs. 90 ± 26 mmHg (P = 0.039) and 15 min, 102 ± 21 vs. 90 ± 23 mmHg (P = 0.023). Hypotensive readings below a mean pressure of 55 mmHg occurred more often in the control group (25 vs. 7, P = 0.047).Continuous monitoring contributes to BP stability in the studied population.NCT02519101.

The large-scale deployment of photovoltaics (PV) is a central pillar in decarbonizing energy systems and reaching climate goals. Although PV is inherently associated to environmental awareness, it is not immune to reputational risks nor exempt of a responsibility for transparency and sustainability leadership. So far, advances in the PV industry have mainly been shaped by cost-reduction targets. We identified in previous works 16 topics where the PV sector comes short in addressing the United Nations Sustainable Development Goal 12 (SDG 12) “Ensure sustainable consumption and production patterns”. In this paper, practical approaches to address each of these sustainability gaps are proposed. The best-practices identified cover all aspects of sustainability as defined by SDG 12–from resource use and hazardous substances through corporate reporting and risk assessment to due diligence and waste management. Insights on methodological needs to improve sustainability assessment and accounting in PV are also provided. The compiled list of actions needed, although not intended to be exhaustive, constitutes a starting point for stakeholders to raise their ambitions and achieve more sustainability in PV value chains.

Bifacial solar cells and modules are a promising approach to increase the energy output of photovoltaic systems, and therefore decrease levelized cost of electricity (LCOE). This work discusses the bifacial silicon solar cell concepts PERT (passivated emitter, rear totally diffused) and BOSCO (both sides collecting and contacted) in terms of expected module cost and LCOE based on in-depth numerical device simulation and advanced cost modelling. As references, Al-BSF (aluminium back-surface field) and PERC (passivated emitter and rear) cells with local rear-side contacts are considered. In order to exploit their bifacial potential, PERT structures (representing cells with single-sided emitter) are shown to require bulk diffusion lengths of more than three times the cell thickness. For the BOSCO concept (representing cells with double-sided emitter), diffusion lengths of half the cell thickness are sufficient to leverage its bifacial potential. In terms of nominal LCOE, BOSCO cells are shown to be cost-competitive under monofacial operation compared with an 18% efficient (≙ pMPP = 18 mW/cm2) multicrystalline silicon (mc-Si) Al-BSF cell and a 19% mc-Si PERC cell for maximum output power densities of pMPP ≥ 17.3 mW/cm2 and pMPP ≥ 18.1 mW/cm2, respectively. These values assume the use of $10/kg silicon feedstock for the BOSCO and $20/kg for the Al-BSF and PERC cells. For the PERT cell, corresponding values are pMPP ≥ 21.7 mW/cm2 and pMPP ≥ 22.7 mW/cm2, respectively, assuming the current price offset (≈50%, at the time of October 2014) of n-type Czochralski-grown silicon (Cz-Si) compared with mc-Si wafers. The material price offset of n-type to p-type Cz-Si wafers (≈15%, October 2014) currently accounts for approximately 1 mW/cm2, which correlates to a conversion efficiency difference of 1%abs for monofacial illumination with 1 sun. From p-type mc-Si to p-type Cz-Si (≈30% wafer price offset, October 2014), this offset is approximately 2.5 mW/cm2 for a PERT cell. When utilizing bifacial operation, these required maximum output power densities can be transformed into required minimum rear-side illumination intensities for arbitrary front-side efficiencies ηfront by means of the performed numerical simulations. For a BOSCO cell with ηfront = 18%, minimum rear-side illumination intensities of ≤ 0.02 suns are required to match a 19% PERC cell in terms of nominal LCOE. For an n-type Cz-Si PERT cell with ηfront = 21%, corresponding values are ≤ 0.11 suns with 0.05 suns being the n-type to p-type material price offset. This work strongly motivates the use of bifacial concepts to generate lowest LCOE. Copyright © 2016 John Wiley & Sons, Ltd.

The development of cost-effective and highly efficient solar cells is a primary goal of current research activities. In this work we investigate two different metallization concepts based on screen-printing technology that are aimed at achieving increased cell conversion efficiency of p-type silicon metal-wrap-through (MWT) solar cell structures. The first approach is the reduction of the pad area of the external rear n-type contacts. Furthermore a multilayer metallization concept is presented that allows for the decoupling of the rear external n-type contact and the p-type silicon base. In this context new pastes for via metallization are investigated-namely low-temperature silver-polymer pastes. The second approach is the optimization of the metallization layout of MWT solar cells to minimize cost of ownership. Therefore the number of contact rows, the finger width, and the number of n-type contact pads per contact row are varied methodically by using analytical simulations. The results are compared with experimental data. Both approaches show a potential for a further conversion efficiency increase of p-type silicon MWT solar cells.

Two-step approaches for front side metallization of silicon wafer solar cells are evaluated regarding their economical properties. The efficiency advantage of such processes is determined in two experiments and translated into an economical advantage using data from latest publications and present module spot market prices. Process costs are estimated based on ISEs extensive data pool and experience with processes. Material usage is varied to reach the economic optimum. An efficiency advantage for the two step approach, compared to standard screen printing, of 0.4%abs with a very conservative process is demonstrated. An adapted process should give an even higher gain. Even for conservative assumptions, cost-effectiveness for the two-step approach is found. Furthermore the flexibility of process approaches with plating as second step is illustrated. Implementation possibilities of two step metallization processes in industrial production lines are discussed. An additional calculation replacing silver with copper shows an even higher economic potential for future metallization solutions. A roadmap comprising several milestones for a stepwise reorganization of industrial solar cell metallization is proposed.

Previous studies on dispensing as an alternative front side metallization process in crystalline silicon photovoltaics demonstrated, how an adaption of paste rheology allows for a precise adjustment of contact finger geometry in a wide range. In order to demonstrate the benefit of this advantage, the analytical simulation tool Gridmaster was extended to observe the effect of various geometrical parameters on solar cell results and manufacturing costs. In addition, respective geometrical parameters of thick film printed contact fingers were determined using a special in house developed tool based on MATLAB. As a result, contact geometries as achievable by means of ultrafine line dispensing are ideally suited for contacting silicon solar cells. Compared with standard fine line single screen printed finger geometries, an efficiency increase of up to Δη = 0.4%abs. as well as a reduction of manufacturing costs of 1 €ct./W p on module level can be achieved using dispensing technology. In order to obtain suitable data, simulation results were compared with solar cell results on industrial pre-processed Cz-Si p-type wafer material applying the novel ten nozzle parallel fine line dispensing unit. Therefore, a new dispensing paste was developed combining optimum optical finger aspect ratios of AR o =0.7 with excellent contacting behavior. A successful first test of applicability already led to a maximum cell efficiency of η = 18.7%, demonstrated on an industrial emitter with a sheet resistance of around R sh = 90 Ω/sq.

During the production of silicon solar cells crack detection systems can help to sort out damaged wafers and reduce wafer breakage before they enter the production line. In order to be cost effective, the crack detection system needs to minimize false detections as much as possible. False detections in crack detection systems occur when bad wafers are not detected or when good wafers are falsely detected as bad. The first error leads to an increase in cell breakage, the second error raises cell costs because non-damaged wafers are sorted out prior to cell processing. In this work a model has been developed to calculate the maximum allowable error rates of crack detection systems in order to achieve a cost per wafer benefit. Therefore a breakage rate dependent throughput calculation, based on manufacturing data, has been implemented. A sensitivity analysis shows that avoiding a high sorting out rate is crucial to favor the implementation of a crack detection system.

Microbial consortia capable of degrading chlorinated hydrocarbons and organic solvents may exist in many contaminated sediments. These native microbial communities with the capability to bioremediate toxicants on-site may prove to be a resource during remediation efforts. For this study, microbial consortia capable of degrading trichloroethylene (TCE) and mixtures of chlorinated and aromatic toxicants were enriched from contaminated sediments and the feasibility of their participation in on-site bioremediation was examined. Batch studies were used to monitor changes in the microbial community structure by monitoring signature fatty acid biomarker trends during TCE degradation. Experimental bioreactors, which utilized sand as a support matrix for the microbial community, were constructed to study TCE and organic mixed waste degradation. In continuously recycled expanded-bed bioreactors and a single-pass packed-bed reactor, mixtures of organic wastes were degraded including: benzene, xylene, toluene, tetrachloroethylene, trichloroethylene, dichloroethylenes and vinyl chloride. Degradation proceeded to >99% depletion for many contaminants. Bioreactors were stable over an 18-month period of operation while using propane or methane plus propane as energy sources and oxygen as the electron acceptor. Biodegradation was most efficient when the bioreactors were pulsed-fed, maintaing the consortia in suboptimal conditions. For the single-pass packed-bed reactor, metabolic efficiencies of 20–70 μmol substrate per μmol TCE degraded were observed for pulse-feeding regimes while continuous substrate availability experiments required >180 μmol substrate per μmol TCE. Continuous feeding experiments utilizing mixtures of organic wastes showed metabolic efficiencies of 83–240 μmol substrate utilization per μmol total organic wastes degraded. These results demonstrated efficient and simultaneous degradation of organic solvents and chlorinated hydrocarbons by environmentally derived microorganisms in laboratory reactors.

In this paper various options to integrate thermal oxidation into industrial cell production are presented, maintaining large parts of the standard cell fabrication process. Both the use of thin (15 nm) and thick (200 nm) wet thermally grown oxides are successfully implemented into pilot production at the Fraunhofer production research platform PV-TEC [1]. Solar cells are fabricated with both type of processes. On large area (149mm2) Cz-Si substrates 18% efficiency have been achieved. Furthermore a cost calculation including process and equipment improvements is carried out for the thermal oxidation process and it is shown that the cost for such a process can be well below 10€ct per wafer for thick and below 5 €ct per wafer for a thin oxide, thus meeting industrial requirements for cost effective production.

This paper presents theory and application of a real-time knowledge based system for fault diagnosis based on the evaluation of fault trees. Fault diagnosis is the art of deriving the underlying causes for a set of symptoms which have occurred with the help of apriori knowledge about process behaviour. The knowledge about the process is structured here in the form of fault trees, which relate causes and effects by AND/OR-elements. The fault trees are evaluated by applying fixed inference rules for each element until the maximum number of unknown states in the fault tree has been determined from the known symptoms. Process dynamics is taken into account by using a specially tailored many-valued logic. For the states which cannot be determined with certainty a probabilistic analysis is done based on conditional probabilties. Then the program EFTAS (=expert fault tree analysis shell) is presented, which incorporates this diagnostic technique. EFTAS works as a real-time analyser of process symptoms transmitted via a serial communications link. Finally, the method is demonstrated by simulation of different faults of a condensate injection seal of a large boiler feed pump in a power station.

The use of endopyelotomy in children with ureteropelvic junction (UPJ) obstruction remains controversial. Although most investigators reported good results with percutaneous or retrograde balloon cautery incision, there are distinct advantages associated with a ureteroscopic approach. Three male children, ages 11, 12 and 17 years, underwent ureteroscopic endopyelotomy for treatment of UPJ obstruction (one primary and two secondary). The procedures were performed using 6F to 8.5F semirigid instruments and the holmium laser. All three patients underwent endopyelotomy without complication. The mean operative time was 80 minutes. Two patients were discharged home the day of the procedure, and the third patient was hospitalized for less than 24 hours postoperatively. With follow-up of 6 to 11 months, two patients are asymptomatic, with no radiographic evidence of obstruction. The 12-year-old boy had continued obstruction following endopyelotomy. At the time of open pyeloplasty, a large crossing vessel was noted, which appeared to be the source of obstruction. Ureteroscopic endopyelotomy can be performed with minimal morbidity and hospitalization in children. Further clinical experience is needed to assess the relative efficacy of this procedure in comparison with other forms of endopyelotomy in children.

Background Elevation of free light chains (FLC) represents B cell activation and has been detected in the autoantibodies positive rheumatologic disorders such as rheumatoid arthritis (RA) and Sjogren syndrome. Psoriatic arthritis (PsA) is typically not accompanied by autoantibodies, however, B cells have been found in PsA synovium (Ref1). Objectives We have conducted a case control study to evaluate the frequency of elevated serum FLC free kappa and free lamda levels in 210 PsA patients to detect polyclonal or monoclonal aberration. Methods Serum FLC levels were measured using the Freelite immunoassay (The Binding Site, Germany) to detect free kappa (normal range 3.3-19.4 mg/l) and lamda (5.7-26.3). Increased free kappa and free lamda levels were defined as polyclonal, a kappa/lamda ratio 1.65 was defined as monoclonal aberration. As controls served healthy controls (n=50), RA patients (n=75) and B-NHLymphoma (n=288). A subgroup analysis was performed after stratification of PsA patients into age, disease duration, development of joint erosions, biological treatment, elevated TNF alpha serum levels. Results PsA patients showed significantly less frequently polyclonal respectively monoclonal increase of FLC (7.1 and 3.8%) compared to RA (10.7 and 10.7%, **p=0.001) and B-NHLymphoma (11.5 and 10.1%, ***p=0.001), but more than in healthy controls (*p=0.001, figure 1). PsA patients with increased TNF alpha serum levels and patients with erosive joint disease had significantly more frequently polyclonal aberrations. Image/graph Conclusions Subgroups of PsA patients showed polyclonal aberrations measured by serum FLC indicating B cell activation in the course of disease. References Cantete JD, et al. Ectopic lymphoid neogenesis in psoriatic arthritis. ARD 2007;66,720-26 Disclosure of Interest G. Assmann Grant/research support from: THE BINDING SITE, Schwetzingen, Germany, put the FREELITE immunoassay at costfree disposal for G Assmann, S. Zinke: None Declared, J. T. Ney: None Declared, M. F. Ong: None Declared, F. Neumann: None Declared, S. Nold: None Declared, M. Pfreundschuh: None Declared

This paper presents theory and application of a real-time knowledge based system for fault diagnosis based on the evaluation of fault trees. Fault diagnosis is the art of deriving the underlying causes for a set of symptoms which have occurred with the help of apriori knowledge about process behaviour. The knowledge about the process is structured here in the form of fault trees, which relate causes and effects by AND/OR-elements. The fault trees are evaluated by applying fixed inference rules for each element until the maximum number of unknown states in the fault tree has been determined from the known symptoms. Process dynamics is taken into account by using a specially tailored many-valued logic. For the states which cannot be determined with certainty a probabilistic analysis is done based on conditional probabilties. Then the program EFTAS (=expert fault tree analysis shell) is presented, which incorporates this diagnostic technique. EFTAS works as a real-time analyser of process symptoms transmitted via a serial communications link. Finally, the method is demonstrated by simulation of different faults of a condensate injection seal of a large boiler feed pump in a power station.

Seven parameter estimation methods have been tested and compared using continuous–time models considering different error definitions to estimate the performance of these methods. The identified processes were simulated on an analog computer. It was found, that the total least squares method in recursive form (RTLS) showed the best performance, followed by the square root algorithms (DSFI and DSFC). Before ca.paring the different methods, the selection of excitation, sampling time and state variable filter parameters was investigated. The comparison itself was done with different signal–to–noise ratios.

Five young males with bilateral nonpalpable testes are presented. In all instances, the testes were localized by laparoscopy. Only one patient had unilateral anorchia at laparotomy which was demonstrated by this technique. Laparoscopy may be more accurate than other nonoperative techniques for localizing nonpalpable testes. Additionally, it facilitates surgical planning and may obviate the need for surgical exploration in some patients.

Die automatische Uberwachung von technischen Prozessen und Fertigungsprodukten erfolgt bisher hauptsachlich durch Grenzwertuberwachung von Signalen. Auftretende Fehler werden durch diese Grenzwertuberwachung alleine oft nur spat erkannt. Deshalb wird zur Uberwachung wichtiger technischer Prozesse Bedienungspersonal eingesetzt, das durch eigene Sensorik (z.B. Gerausch, Temperatur, Schwingungen, Stellkrafte), Mesprotokolle und langjahrige Erfahrung fruhe Informationen uber Prozesveranderungen erhalt. Mochte man nun die Uberwachung automatisieren, so liegt es zunachst nahe, zusatzliche Sensoren einzufuhren und das Bedienungspersonal — Expertenwissen in Rechnern abzulegen.