Documents published in Scipedia

• Renewable energy auctions in South Africa outshine feed-in tariffs

  A. Eberhard, T. Kåberger

  Energy Science & Engineering (2017).

  
  

  Abstract

  South Africas Renewable Energy Independent Power Producer Procurement Program has run four competitive tenders/auctions since 2011, which have seen US$19 billion in private investment, and electricity prices of wind power falling by 46% and solar PV electricity prices by 71%, in nominal terms. Competitive tenders were introduced after an unsuccessful attempt to implement feed-in tariffs. The tenders incorporated standard, nonnegotiable contract documents, including 20-year Power Purchase Agreements and an Implementation Agreement whereby the Government of South Africa back-stops IPP payments by the national utility, Eskom. All of these projects have reached financial close to date and some are already delivering power to the grid. The financing success has been due in part to the requirements for commercial banks to undertake a thorough due diligence of projects prior to bids being offered. The details of the policy package described may be useful for other policy makers in countries developing policies for renewable energy deployment.

  Abstract
  South Africas Renewable Energy Independent Power Producer Procurement Program has run four competitive tenders/auctions since 2011, which have seen US$19 billion in private [...]

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• Comprehensive study of performance degradation of field-mounted photovoltaic modules in India

  R. Dubey, S. Chattopadhyay, V. Kuthanazhi, A. Kottantharayil, C. Solanki, B. Arora, K. Narasimhan, J. Vasi, B. Bora, Y. Singh, O. Sastry

  Energy Science & Engineering (2017).

  
  

  Abstract

  The All India Survey of Photovoltaic Module Reliability 2014 is an enhanced version of the survey conducted in the previous year, with detailed characterization of PV modules including current-voltage, infrared and electroluminescence imaging, visual inspection, insulation resistance test and interconnect breakage test. More than a thousand modules were inspected in the field and the main results of the survey are presented in this paper. The average Pmax degradation rate for the so-called ‘good’ modules (Group X) is 1.33%/year which is higher than that commonly projected by manufacturers, and widely employed in financial calculations. Modules falling in the ‘not-so-good’ category (Group Y) show even higher degradation rates, and it is at least partly due to higher number of micro-cracks in the modules, and increased degradation of the packaging materials like encapsulant, backsheet, etc. Modules in ‘Hot’ climates degrade faster than modules in the ‘Non-Hot’ climates. Degradation in fill factor is the primary cause for performance degradation in the young modules (ages

  Abstract
  The All India Survey of Photovoltaic Module Reliability 2014 is an enhanced version of the survey conducted in the previous year, with detailed characterization of PV modules [...]

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• Performance analysis of a tower solar collector-aided coal-fired power generation system

  L. Duan, X. Yu, S. Jia, B. Wang, J. Zhang

  Energy Science & Engineering (2017).

  
  

  Abstract

  In this paper, a tower solar collector-aided coal-fired power generation (TSCACPG) system is proposed and studied in order to save the fossil energy and protect the environment. The integration scheme of tower solar collector and conventional coal-fired power plant is proposed. Based on the simulation platform TRNSYS, the TSCACPG system model is established and the dynamic performance of the TSCACPG system with the operating mode of coal saving is studied. The TSCACPG system performances of 1 day and 1 year are all discussed by using the DNI data of typical year in Chinese typical city of Dunhuang. Then, the sensitivity analysis of the TSCACPG system is carried out by changing the heliostat field scale (the size of the molten salt tower also changes accordingly). The annual performance of the TSCACPG system is also acquired. In consideration of the economic costs, the heliostat field area with the maximum annual solar-to-electric efficiency is selected as the optimal value. The results show that, for the case studied, the optimal heliostat field area is 101, 400 m2, and the maximum annual solar-to-electric efficiency is 16.74%. And under the optimal situation, the standard coal consumption rate of the original coal-fired power plant is reduced from 301.5 g/kWh to 294.5 g/kWh.

  Abstract
  In this paper, a tower solar collector-aided coal-fired power generation (TSCACPG) system is proposed and studied in order to save the fossil energy and protect the environment. [...]

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• Design and experimental execution of a microcontroller (μC)-based smart dual-axis automatic solar tracking system

  S. Das, S. Chakraborty, P. Sadhu, O. Sastry

  Energy Science & Engineering (2017).

  
  

  Abstract

  Detail analysis of microcontroller (μC)-based smart dual-axis automatic solar tracking system utilizable for different purpose is presented in this paper. Working of the proposed smart tracking system is based on the automatic rotation of photovoltaic (PV) panel depending on the intensity of sun light. It will help in maintaining the alignment of PV panels with the Sunlight to obtain maximum solar power at any instance. Intensity of sunlight on a particular alignment of solar PV panel varies throughout the day. As the intensity of light on PV panel decreases the proposed smart tracking system has the intelligence to automatically redirect the panel alignment to get maximum intensity of light. Four Light Dependent Resistor (LDR) sensors are placed on the surface of the PV panel to detect the intensity of light. Two servomotors are employed in the back side of PV panel system to align the panel with maximum luminous intensity. Design and construction of the proposed tracking system is presented to measure the efficiency over the fixed PV panel. Experimental results indicate that the power output of the PV system, using the proposed tracking system is increased up to 19.73% compare to the traditional fixed PV panel. The efficiency of the proposed design is considerably higher and comparable to the existing design which has the average efficiency around 12–15%.

  Abstract
  Detail analysis of microcontroller (μC)-based smart dual-axis automatic solar tracking system utilizable for different purpose is presented in this paper. Working of the [...]

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• Estimating the specific chemical exergy of municipal solid waste

  F. Eboh, P. Ahlström, T. Richards

  Energy Science & Engineering (2017).

  
  

  Abstract

  A new model for predicting the specific chemical exergy of municipal solid waste (MSW) is presented, the model is based on the content of carbon, hydrogen, oxygen, nitrogen, sulfur, and chlorine on a dry ash-free basis (daf). The proposed model was obtained from estimations of the higher heating value (HHV) and standard entropy of MSW using statistical analysis. The ultimate analysis of 56 different parts of MSW was used for the derivation of the HHV expression. In addition, 30 extra parts were used for validation. One hundred and seventeen relevant organic substances that represented the main constituents in MSW were used for derivation of the standard entropy of solid waste. The substances were divided into different waste fractions, and the standard entropies of each waste fraction and for the complete mixture were calculated. The specific chemical exergy of inorganic matter in the waste was also investigated by considering the inorganic compounds in the ash. However, as a result of the extremely low value calculated, the exergy of inorganic matter was ignored. The results obtained from the HHV model show a good correlation with the measured values and are comparable with other recent and previous models. The correlation of the standard entropy of the complete waste mixture is less accurate than the correlations of each individual waste fraction. However, the correlations give similar results for the specific chemical exergy, indicating that HHV has a greater impact when estimating the specific exergy of solid waste than entropy.

  Abstract
  A new model for predicting the specific chemical exergy of municipal solid waste (MSW) is presented, the model is based on the content of carbon, hydrogen, oxygen, nitrogen, [...]

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• Technical mapping of solar PV for ISM-an approach toward green campus

  S. Chakraborty, P. Sadhu, N. Pal

  Energy Science & Engineering (2017).

  
  

  Abstract

  This paper aims toward the first step for green campus approach for Indian School of Mines (ISM) campus. Comparative study of the performances for nine different commercialized solar panels made of Maxeon Cell Technology, HIT (Heterojunction with Intrinsic Thin layer), monocrystalline silicon (Mono C-Si), polycrystalline silicon (Poly C-Si), Micromorph, SCHOTT, amorphous silicon (a-Si), CIGS, CdTe technologies in the environmental condition of ISM are presented in this paper. This system suggests to supply the daytime electricity demand of ISM campus as well as efficient use of the huge roof areas of different buildings to setting up the photovoltaic plant. This system ensures a daily mean reduction of 8 MWh electricity consumption from grid. The outcome of this study is that a superior performance is noted for modules made of amorphous silicon technology under the typical temperature variant and dry environmental condition of ISM campus.

  Abstract
  This paper aims toward the first step for green campus approach for Indian School of Mines (ISM) campus. Comparative study of the performances for nine different commercialized [...]

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• Developing new perspectives on the energy trilemma

  A. Carrick

  Energy Science & Engineering (2017).

  
  

  Abstract

  The energy group of SCI (Society of Chemical Industry) was host for an event on 28th March 2017 at SCI Headquarters in London (UK) with a meeting on the important topic of the energy trilemma (sustainable, affordable and secure supply of energy). Alexandra Carrick gives an overview of the event.

  Abstract
  The energy group of SCI (Society of Chemical Industry) was host for an event on 28th March 2017 at SCI Headquarters in London (UK) with a meeting on the important topic of [...]

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• Heterogeneous and homogenous catalysts for hydrogen generation by hydrolysis of aqueous sodium borohydride (NaBH4) solutions

  P. Brack, S. Dann, K. Wijayantha

  Energy Science & Engineering (2017).

  
  

  Abstract

  It is clear that in order to satisfy global energy demands whilst maintaining sustainable levels of atmospheric greenhouse gases, alternative energy sources are required. Due to its high chemical energy density and the benign by-product of its combustion reactions, hydrogen is one of the most promising of these. However, methods of hydrogen storage such as gas compression or liquefaction are not suitable for portable or automotive applications due to their low hydrogen storage densities. Accordingly, much research activity has been focused on finding higher density hydrogen storage methods. One such method is to generate hydrogen via the hydrolysis of aqueous sodium borohydride (NaBH4) solutions, and this has been heavily studied since the turn of the century due to its high theoretical hydrogen storage capacity (10.8 wt%) and relatively safe operation in comparison to other chemical hydrides. This makes it very attractive for use as a hydrogen generator, in particular for portable applications. Major factors affecting the hydrolysis reaction of aqueous NaBH4 include the performance of the catalyst, reaction temperature, NaBH4 concentration, stabilizer concentration, and the volume of the reaction solution. Catalysts based on noble metals, in particular ruthenium (Ru) and platinum (Pt), have been shown to be particularly efficient at rapid generation of hydrogen from aqueous NaBH4 solutions. However, given the scarcity and expense of such metals, a transition metal-based catalyst would be a desirable alternative, and thus much work has been conducted using cobalt (Co) and nickel (Ni)-based materials to attempt to source a practical option. “Metal free” NaBH4 hydrolysis can also be achieved by the addition of aqueous acids such as hydrochloric acid (HCl) to solid NaBH4. This review summarizes the various catalysts which have been reported in the literature for the hydrolysis of NaBH4.

  Abstract
  It is clear that in order to satisfy global energy demands whilst maintaining sustainable levels of atmospheric greenhouse gases, alternative energy sources are required. [...]

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• An old solution to a new problem? Hydrogen generation by the reaction of ferrosilicon with aqueous sodium hydroxide solutions

  P. Brack, S. Dann, K. Wijayantha, P. Adcock, S. Foster

  Energy Science & Engineering (2017).

  
  

  Abstract

  The chemical hydrogen storage properties of ferrosilicon were investigated. A hydrogen yield of ~4.75 wt.% (with respect to the mass of ferrosilicon) was estimated by the reaction of varying quantities of ferrosilicon with 5 mL of 40 wt.% sodium hydroxide solution. The reaction of ferrosilicon with aqueous sodium hydroxide solution to form hydrogen was found to have an activation energy of 90.5 kJ mol−1 by means of an Arrhenius plot. It was observed that the induction period of the hydrogen generation reaction varies exponentially with temperature. Although this combination of high activation energy and a lengthy induction period at low temperatures reduces the attractiveness of ferrosilicon for portable hydrogen storage applications unless methods can be developed to accelerate the onset and rate of hydrogen generation, its low cost and widespread availability make it attractive for further studies focused on higher temperature stationary applications.

  Abstract
  The chemical hydrogen storage properties of ferrosilicon were investigated. A hydrogen yield of ~4.75 wt.% (with respect to the mass of ferrosilicon) was estimated by the [...]

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• Numerical computation of a large-scale jet fire of high-pressure hydrogen in process plant

  C. Jang, S. Jung

  Energy Science & Engineering (2017).

  
  

  Abstract

  Due to numerous hazardous chemicals to handle, the process plant industry has a higher risk of fire, explosion, and toxic release than other industries. Reviewing the accidents at process plants in the past, it is clear that fire accidents occur with the highest frequency, leading this study to consider accidental fire scenarios at process plants. For the scenario of an incident, a jet fire involving a massive amount of hydrogen gas to be processed or delivered at the process plant has been selected. The analysis of incident outcome resulting from the hydrogen jet fire has been implemented through the computational fluid dynamics simulation methodology Kameleon FireEx. Based on the outcome of this simulation, the consequences of a jet fire with high temperature and heat radiation are analyzed and evaluated. In addition, the results from Phast ver. 7.11 simulation for the same scenario are presented for comparison and further validation.

  Abstract
  Due to numerous hazardous chemicals to handle, the process plant industry has a higher risk of fire, explosion, and toxic release than other industries. Reviewing the accidents [...]

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