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Journal articles on the topic 'Expected energy not supplied'
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Wang, M. Q., H. B. Gooi, and S. X. Chen. "Optimising probabilistic spinning reserve using an analytical expected-energy-not-supplied formulation." IET Generation, Transmission & Distribution 5, no. 7 (2011): 772. http://dx.doi.org/10.1049/iet-gtd.2010.0805.
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Nazmul Huda, A. S., and Rastko Živanovic. "Estimation of Distribution Systems Expected Energy Not Supplied Index by Multi-level Monte Carlo Method." Electric Power Components and Systems 47, no. 9-10 (June 15, 2019): 810–22. http://dx.doi.org/10.1080/15325008.2019.1628120.
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Ashour, Abshir, Taib Iskandar Mohamad, Kamaruzzaman Sopian, Norasikin Ahmad Ludin, Khaled Alzahrani, and Adnan Ibrahim. "Performance optimization of a photovoltaic-diesel hybrid power system for Yanbu, Saudi Arabia." AIMS Energy 9, no. 6 (2021): 1260–73. http://dx.doi.org/10.3934/energy.2021058.
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<abstract> <p>In the rural areas of Saudi Arabia, which are not connected to the national grid, electricity is supplied mainly from diesel generators. This is not just a non-renewable energy source, but it has also resulted in environmental damage and may be hazardous to human health. In order to mitigate the problem, integration with a solar photovoltaic system is proposed. A Photovoltaic-Diesel Hybrid System (PvDHS) was designed, analyzed, and optimized based on the climate data of Yanbu, Saudi Arabia. Measured local solar insolation and climate data were used in the Hybrid Optimization Model for Electric Renewables (HOMER) software with different system components and configurations in order to optimize the design that yields the best energy cost. A system consisting of a 3 kW photovoltaic system, a 2 kW diesel engine, a 1 kW converter, and 14 kWh batteries were identified to be the most cost-effective for the average daily electricity demand of 10.5 kWh. The total Net Present Cost (NPC) of this system is ＄17, 800, a reduction of 50% over the ＄35, 770 cost of the diesel-only system. The PvDHS useful electrical energy is found to be ＄0.36/kWh, while the Cost of Energy (COE) of the diesel-only system is ＄0.72/kWh. The system is expected to pay for itself in 2.8 years and reduce CO<sub>2</sub> emissions by 8110 kg per year.</p> </abstract>
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Jacome, Veronica, Noah Klugman, Catherine Wolfram, Belinda Grunfeld, Duncan Callaway, and Isha Ray. "Power quality and modern energy for all." Proceedings of the National Academy of Sciences 116, no. 33 (July 29, 2019): 16308–13. http://dx.doi.org/10.1073/pnas.1903610116.
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“Modern energy for all,” an internationally supported initiative to connect populations to electricity services, is expected to help reduce poverty-induced vulnerabilities. It has become a primary strategy for meeting sustainable development goals, especially in sub-Saharan Africa. However, when electricity is supplied by a capacity-constrained grid to a resource-constrained population, the service quality can vary both spatially and temporally. This research explores the quality of electricity services based on a case study of Unguja, Tanzania. Using 1) open-ended interviews, 2) detailed electricity-systems monitoring, and 3) household surveys, we show how voltage quality varies significantly, even within highly localized settings. Fluctuations result in dim lights at best and power outages and broken appliances at worst, denying many Unguja residents the expected benefits of access to modern energy. By combining an extensive understanding of the physical system together with interviews and surveys, this work presents a unique mapping of voltage quality in a system that is financially and physically constrained and highlights the consequences of poor-quality service for poor users.
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Alsaedi, Malik Abdulrazzaq, Hussein Jumma Jabir, and Baraa Munqith Albaker. "Load shifting impact on generating adequacy assessment during peak period." Indonesian Journal of Electrical Engineering and Computer Science 25, no. 3 (March 1, 2022): 1217. http://dx.doi.org/10.11591/ijeecs.v25.i3.pp1217-1226.
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<p><span>The load shifting technique is widely implemented in electrical power generation due to its considerable impact on system reliability. The evaluation of load shifting benefits towards the adequacy of generation systems requires an accurate assessment. If the generation unit’s capacity is insufficient to meet the system load, then assistance is required from alternative sources. Load shifting, as a primary demand-side management technique, is used efficiently in electrical power networks given that the energy clipped/curtailed owing to load curtailment and peak clipping can be recovered during the off-peak period. The reliability of a generic framework for the prospective integration of a load shifting technique, with preventative and corrective actions as alternatives to peaking units, is investigated in this study. The optimal rate of load shifting in terms of expected energy not supplied is also investigated. Results show that preventive load shifting (PLS) can act as peaking units when the total generated capacity is within specific limits. Meanwhile, corrective load shifting can act as a better alternative than PLS and peaking units. To calculate expected energy not supplied, sequential Monte Carlo simulation is utilized. This study is conducted using the IEEE reliability test system.</span></p>
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Lee, Junghoon, and Gyung-Leen Park. "Integrated Coordination of Electric Vehicle Operations and Renewable Energy Generation in a Microgrid." International Journal of Electrical and Computer Engineering (IJECE) 7, no. 2 (April 1, 2017): 706. http://dx.doi.org/10.11591/ijece.v7i2.pp706-712.
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This paper designs a microgrid energy controller capable of creating a charging or discharging schedule for electric vehicles (EVs), aiming at leveraging the integration of renewable energy and shaving the peak load in the microgrid. Dynamically activated on each time slot to cope with the prediction error for the power consumption and the renewable energy generation, the controller calculates the number of EVs to charge or make discharge first. Then, a greedy algorithm-based scheduler selects EVs according to the expected energy potential during their stays. The potential is the integral of a supply-demand margin function from the current time to the expected departure time. A simulator is implemented for performance evaluation, comparing with uncoordinated scheduling, according to the number of EVs as well as the behavior of energy load and production. The experiment result shows that the proposed scheme can reduce the energy waste by 16.9 %, cut down the microgrid-level energy insufficiency by 12.2 %, and enhance the amount of electricity supplied to EVs by 37.3 %, respectively, for given parameter setting.
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HR, Herman. "ANALISIS KINERJA PHOTOVOLTAIK PADA STAND ALONE." Jurnal Sinergi Jurusan Teknik Mesin 15, no. 2 (May 26, 2019): 203. http://dx.doi.org/10.31963/sinergi.v15i2.1195.
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Solar Power Generation (SPG), or often called solar photovoltaic system, is one application of the use of solar energy as a source of electrical energy. This PLTS utilizes solar cells (photovoltaic) to generate electrical energy. The aimed of this research were to know the performance of PLTS installed power 150 Wp stand alone and know how much power capacity can be supplied by PLTS. Solar Power Generation (Photovoltaics) most influenced by the intensity of sunlight depending on each region. Module with a capacity of 150 Wp has been able to produce a mean power of 133.7 Watt / day. The expected output in this research was to create a good system and can contribute to student labs in laboratories and as an alternative source of energy in the Department of Mechanical Engineering and Maintenance, and beneficial for the development of electric power generation system in district of Fak-fak. This research was also expected to produce Scientific Publications in local journals.
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Alshoshan, Karima, Wedad El-Osta, Yosof Kahlifa, and Ibrahim Saleh. "Feasibility Study of Zero Energy Houses: Case Study of Magrun City - Libya." Solar Energy and Sustainable Development Journal 7, no. 2 (December 31, 2018): 59–77. http://dx.doi.org/10.51646/jsesd.v7i2.41.
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The residential load is one of the largest consumers of the electric energy in Libya that could be supplied by renewable energies. Renewable energy technologies and systems can be a good solution to build “Zero Energy Buildings”. A zero-energy house is proposed for Maqrun city. It is intended to use wind turbine with batteries as a storage system to supply electric energy demand for this house. The intended house average daily electric energy demand is estimated to be 35 kWh/day. Two WECS were selected to supply the energy demand each of size 6 kW. Th energy produced by the selected wind energy conversion system (WECS) is about 23,894 kWh/yr and the expected capacity factor at the site is about 23%. Modeling of energy demand of the house and simulation of its performance was performed using excel sheets and HOMER softare.
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Baker, G. L., and W. R. Skerman. "THE SIGNIFICANCE OF COAL SEAM GAS IN EASTERN QUEENSLAND." APPEA Journal 46, no. 1 (2006): 329. http://dx.doi.org/10.1071/aj05018.
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The commercial production of coal seam gas [CSG] in Australia is only a decade old. Over the last 10 years it has become a significant part of the Australian gas industry, particularly in Queensland where about 31 PJ or 30% of all natural gas used in the State was recovered from coal seams in eastern Queensland. In 2005 CSG was expected to have supplied 55 PJ or 44 % of the eastern Queensland gas demand. The mining, mineral processing and power generations in northwest Queensland, serviced by the Carpentaria Gas Pipeline, will continue to use gas from the Cooper-Eromanga Basin.The CSG industry is reaching a stage of maturity following the commissioning of a number of fields while some significant new projects are either in the commissioning phase or under development. By the end of 2008 CSG production in Queensland is expected to reach 150 PJ per year, the quantity needed to meet Gas Supply Agreements for CSG that are presently in place.Certified Proved and Probable (2P) gas reserves at 30 June 2005 in eastern Queensland were calculated to be 4,579 PJ, of which 4,283 PJ were CSG. Gas reserves (2P) for eastern Queensland a decade earlier were less than 100 PJ with those for CSG being less than 5 PJ.The coal seam gas industry in both the Bowen and Surat basins—which includes major gas producers such as Origin Energy Limited and Santos Limited along with smaller producers such as Arrow Energy NL, CH4 Gas Limited, Molopo Australia Limited and Queensland Gas Company Limited—is now accepted by major gas users as being suppliers of another reliable source of natural gas.
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Shaddiq, Syahrial. "A Nexus among Reliability Improvement of Distribution System with Optimal Placement and Capacity of Wind-Based Distributed Generation Management." Journal ICTEE 2, no. 2 (November 23, 2021): 1. http://dx.doi.org/10.33365/jictee.v2i2.1174.
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Along with the world population growth, the need for a source of electrical energy is higher, so a reliable system with higher capacities is expected. Renewable energy becomes an alternative that supports the goal of reducing the risk of disruption, thus increasing the distribution system’s reliability. A lot of industries and public settlement uses renewable sources of energy as an alternative power supply to comply their energy needs. This research uses wind turbine as a source of renewable energy in the distributed generation (DG). However, the required investment in wind-based DG is commonly considered too costly to deploy and require a proper planning on its placement method. The flower pollination algorithm (FPA) method could be a solution to achieve optimal placement of wind-based DG, thus increase the distribution system’s reliability, which is indicated by minimum energy not supplied (ENS) index.
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Peñalvo-López, Elisa, Vicente León-Martínez, Joaquín Montañana-Romeu, and Javier Cárcel-Carrasco. "Passive Reactive Power Compensators for Improving the Sustainability of Three-Phase, Four-Wire Sinusoidal Systems Supplied by Unbalanced Voltages." Sustainability 13, no. 20 (October 9, 2021): 11134. http://dx.doi.org/10.3390/su132011134.
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Compensation of reactive power is necessary in power systems due to economical, energetic, and environmental reasons. Reactive power increases energy power losses and carbon dioxide emissions in distribution lines and power transformers. However, capacitor banks used in most industrial applications do not significantly reduce energy losses in lines and transformers when supply voltages and loads are unbalanced and therefore do not fully improve the sustainability of distribution networks. This fact is explained in this paper using positive-, negative-, and zero-sequence reactive power components in three-phase, four-wire sinusoidal power systems supplied with unbalanced voltages. Likewise, several devices have also been developed for the compensation of the total reactive power and, specifically, for each of its components in these power systems. Comparing the effectiveness of these reactive compensators and other well-known passive compensators as capacitor banks on the sustainability improvement of the electrical installation of an actual industry, reductions between 20% and 100% in energy losses and carbon dioxide emissions, caused by circulation of reactive currents in transformer and lines, can be expected depending on the type of compensator used.
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Li, Yingxiao, and Jianheng Zhou. "Sustainable Supplier’s Equilibrium Discount Strategy under Random Demand." Sustainability 14, no. 8 (April 16, 2022): 4802. http://dx.doi.org/10.3390/su14084802.
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This paper examines a sustainable supplier’s price discount strategy in a competitive environment as it considers building a two-level supply chain system consisting of two suppliers and a single retailer under the condition of uncertain demand, and investigates the impact of the suppliers’ price discount strategy on the retailer’s expected profits. We find that the sustainable supplier’s expected profit increases as the price discount increases. When only the sustainable supplier offers a discount, the retailer’s purchasing cost will increase with the degree of the discount; when both suppliers provide a discount, the sustainable supplier’s expected profit decreases as the price discount increases, while the retailer’s purchasing cost will decrease.
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Saitoh, Y., T. Nakatani, T. Matsushita, T. Miyahara, M. Fujisawa, K. Soda, T. Muro, et al. "Twin helical undulator beamline for soft X-ray spectroscopy at SPring-8." Journal of Synchrotron Radiation 5, no. 3 (May 1, 1998): 542–44. http://dx.doi.org/10.1107/s090904959701902x.
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A very high resolution soft X-ray beamline, BL25SU, has been designed and is under construction at SPring-8. Completely right or left circularly polarized light is supplied on a common axis of a newly designed twin helical undulator. A helicity modulation up to 10 Hz can be performed using five kicker magnets. The fundamental radiation covers the region 0.5–3 keV. Higher-order radiation is rather weak on the axis. A monochromator with varied-line-spacing plane gratings is installed to cover the region below 1.5 keV. A very high resolution beyond 104 is expected for the whole energy region.
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Nofianto, Catur, and Rizal Fajar Rahmawan. "ANALISA SISTEM PENCAHAYAAN DAN PENGKONDISI UDARA GEDUNG RAJAWALI RSUP DR. KARIADI SEMARANG." MEDIA ELEKTRIKA 11, no. 2 (December 13, 2019): 75. http://dx.doi.org/10.26714/me.11.2.2018.75-84.
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EnglishWith the research Rajawali Building energy audits at the General Hospital Center Kariadi doctor is expected to generate electrical energy consumption in the policy environment Rajawali Building. Electrical energy is supplied to the use of tools such as lighting systems, HVAC system (AC), and the utility system (pump). The intensity value of energy consumption for building Rajawali General Hospital Physicians Kariadi Semarang based on a calculation of the total recapitulation electricity consumption per building area last year was 98.69 kWh / m2 / year. Energy management systems in Rajawali Building General Hospital Physicians Kariadi Semarang already seen their energy saving measures in the building. Installation of energy metering has been done that will allow the monitoring system energy use. Doctors Hospital Kariadi Rajawali building using electrical energy in 2016 amounted to 1,826,775 kWh / year. The composition of the major energy users in the building occupied by the AC Eagles by 79%, the lighting is 11% and 10% pump.IndonesianDengan adanya penelitian audit energi di Gedung Rajawali Rumah Sakit Umum Pusat Dokter Kariadi ini diharapkan dapat menghasilkan kebijakan pemakaian energi listrik di lingkungan Gedung Rajawali. Energi listrik disuplai untuk penggunaan peralatan antara lain , sistem penerangan, sistem tata udara ( AC ), dan sistem utilitas ( pompa ). Nilai Intensitas konsumsi energi untuk Gedung Rajawali Rumah Sakit Umum Pusat Dokter Kariadi Semarang berdasarkan perhitungan dari total rekapitulasi pemakaian listrik per luas bangunan satu tahun terakhir adalah 98,69 kWh / m2 / Tahun. Sistem manajemen energi yang ada di Gedung Rajawali Rumah Sakit Umum Pusat Dokter Kariadi Semarang sudah terlihat adanya langkah-langkah penghematan energi khusus di gedung ini. Pemasangan metering energi sudah dilakukan sehingga akan memudahkan sistem monitoring penggunaan energi. Gedung Rajawali RSUP Dokter Kariadi menggunakan energi listrik pada tahun 2016 sebesar 1.826.775 kWh / tahun. Komposisi pengguna energi utama di Gedung Rajawali ditempati oleh AC sebesar 79 %, pencahayaan adalah 11% dan pompa 10 %.
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Duclos, Jean. "A survey of the LEAR experimental programme." Canadian Journal of Physics 67, no. 12 (December 1, 1989): 1186–92. http://dx.doi.org/10.1139/p89-199.
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During the first period of operation of the low energy antiproton ring (LEAR) from 1983 to 1986, antiproton beams were supplied for several experiments at an intensity between 105 and [Formula: see text]. A first exploration was made of several subjects in physics, including [Formula: see text] and [Formula: see text]–nucleus interactions, [Formula: see text]–atoms, and various annihilation channels. After an improvement by a factor of 5 for the [Formula: see text] production at CERN in 1987, a new generation of experiments is expected to complete the previous studies and to cover new subjects concerning fundamental symmetries.
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ROTAR, DAN, and GEORGE CULEA. "ELECTRICITY METER WITH THE FACILITY TO DETERMINE THE QUALITY OF THE ELECTRICITY SUPPLIED." Journal of Engineering Studies and Research 27, no. 3 (January 10, 2022): 74–78. http://dx.doi.org/10.29081/jesr.v27i3.290.
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Many areas of activity face the problem of electricity quality. At the same time, diagnosing the quality of the energy provided makes it possible to identify and remedy problems that have arisen in the system. Advanced signal processing techniques and the use of advanced systems allow for a complex analysis of the phenomenon. The paper presents an electricity meter equipped with an electricity quality analysis system. It was developed based on the Xilinx Artix-7 programmable logic matrix. A Digilent Arty A7 development board was used due to its design and experimentation facilities. The developed system determines the power consumed and the main elements that define the quality of electricity: harmonics and other deviations from the frequency of nominal power supply, flicker, voltage gaps, voltage variations, transient surge, temporary surge, etc. The possibility of using an embedded system equipped with the Microblaze soft microprocessor, the existence of a 12-bit analog-digital converter and the maximum sampling frequency of 1 MSPS and the possibility of assisted design allows to obtain a measurement system with superior characteristics. The results obtained and the experiments carried out confirm the expected performance for the electricity meter.
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Софийский К. К., Стасевич Р. К., Агаев Р. А., Власенко В. В., and Дудля Е. Е. "ТЕХНИКО-ЭКОНОМИЧЕСКИЕ АСПЕКТЫ КОГЕНЕРАЦИИ УГЛЕВОДОРОДНЫХ ГАЗОВ." International Journal of Innovative Technologies in Economy 2, no. 6(18) (July 1, 2018): 23–26. http://dx.doi.org/10.31435/rsglobal_ijite/01072018/5939.
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The subject of researches are the regularities of the effective operation of information, resource and energy saving technology for the gases utilization from coal mines and metallurgical industries. The aim of the work is to present the technical and economic aspects of the information resource and energy saving process for the gases utilization from coal deposits and mines. As the result, the information about a new method for increasing the accuracy of automated commercial metering of coal gas, supplied to the Ukrainian gas-transport system, was provided, the regularities, governing the energy efficiency of controlling of the air/gas ratio from the oxygen concentration in the flue gases of the boiler unit, and the criterion of energy-efficient management were established. The calculation of the expected annual economic effect from the implementation of the control station “DIYA”, using the presented developments, was given.
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Stonis, Danylo. "DIVERSIFICATION OF GAS SUPPLIES AS A CORNERSTONE OF GAS SECURITY IN THE FRAMEWORK OF THE THREE SEAS INITIATIVE." Three Seas Economic Journal 2, no. 2 (June 29, 2021): 1–8. http://dx.doi.org/10.30525/2661-5150/2021-2-1.
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The article overviews approaches to the diversification of gas supplies in the framework of the Three Seas Initiative. The modern geopolitical situation in Eastern and Central Europe is characterized by transformation processes in the energy sector. Due to the implementation of decarbonization policy in the European Union and subsequent shift from coal as a main energy source, a need in alternative fuel sources, such as natural gas, emerges. Therefore, a significant increase in natural gas consumption is expected, which raises a number of issues, such as dependence on a single gas supplier and orientation of the EU’s gas transmission system in East-West direction only. This issue is crucial for Eastern and Central European states, due to the underdeveloped gas infrastructure in the region and heavy dependence on a single gas supplier, such as Russia or Turkey. Hence, the Three Seas Initiative is considered as a powerful tool, designed to develop energy, transport and digital infrastructure of the region in the North-South direction, where one of the most potentially promising projects within the framework of the Three Seas Initiative is represented by the development of gas infrastructure, aimed at solving the diversification of supplies in the gas market in Eastern and Central Europe. The implementation of developed gas infrastructure and diversification of gas supplies consists of several regional projects that are relevant for those countries in the region in which they are implemented in particular and for all member states of the Three Seas Initiative in general. The main purpose of the implementation of these projects is the creation of a unified natural gas transportation infrastructure in Eastern Europe along the North-South axis. The result of such a grand reorganization in the field of gas supplies to Europe will be an increase in the number of independent suppliers in the European gas market and a decrease in the dependence of the EU countries on gas supplies from Russia. In the article, the author traced in detail the tendency of the formation of energy infrastructure along the North-South axis with focus on the projects that are being implemented by each of the participating countries within the framework of the Three Seas Initiative. This approach allows to assess the scale and integrity of the gas transportation infrastructure, that is being created in the Eastern Europe region and its contribution to the common European energy security policy.
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Rech, Sergio, Stefano Casarin, Carlos Santos Silva, and Andrea Lazzaretto. "University Campus and Surrounding Residential Complexes as Energy-Hub: A MILP Optimization Approach for a Smart Exchange of Solar Energy." Energies 13, no. 11 (June 6, 2020): 2919. http://dx.doi.org/10.3390/en13112919.
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An effective way to enlarge the utilization of renewable energy consists in creating a correct interface between producers, consumers, and storage devices, i.e., a so-called “energy hub”. This opens a difficult challenge, especially in the urban areas where the availability of room for the installation of renewable plants is limited. This paper considers a university campus in the center of Lisbon that requires a significant amount of electricity and natural gas to support the internal activities. The idea is to fulfil part of the energy consumption of the campus with the excess of energy supplied by solar systems installed in the surrounding residential buildings. The goal is to find the number and type of solar equipment that maximize the reduction of annual energy costs of both residents and campus, where the campus is seen as a virtual storage. Results of the optimization show that, considering the best-exposed 100 buildings in a radius of 500 m around the campus, the campus can reduce the annual energy expenses up to 8.61%, whereas the money-saving for the residents is of the order of 24% to 29%, depending on solar exposure. A sensitivity analysis shows also the higher benefits for both the campus and users deriving from expected decreasing costs of photo-voltaic (PV) panels.
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Chojna, Janusz, Miklós Losoncz, and Paavo Suni. "Shale Energy Shapes Global Energy Markets." National Institute Economic Review 226 (November 2013): F40—F45. http://dx.doi.org/10.1177/002795011322600115.
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Unconventional resources of crude oil and natural gas – shale energy – increased significantly in the US in the early 2000s, triggered by the strong rise in the price of crude oil and technical advances in production. The US is a clear forerunner in the production of shale energy, due to its existing knowledge and infrastructure. The rest of the world is following, although negative environmental effects and other factors have obstructed the diffusion of new extraction methods. In Europe, Polish production is expected to start in the next few years, although environmental concerns are delaying the onset. The rise in the importance of shale energy will increase global oil and gas production markedly. The rising global supplies will improve global energy security in the long run and help to stabilise the large international price differences for natural gas.
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Zheng, Xiao Li, Ji Chun Liu, Jia Yi Li, Yun Xia Wu, Fang Zhang, Hong Hui Chen, Xiang Yang An, and Chen He. "The Reserve Capacity Model Based on the Idea of Scenario in Power System." Advanced Materials Research 1008-1009 (August 2014): 173–78. http://dx.doi.org/10.4028/www.scientific.net/amr.1008-1009.173.
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According to the impact of the wind power prediction uncertainty on the power system reserve capacity, the idea of scenario is introduced to the stochastic programming model. The method of scenario is used to simulate the uncertainty model of the wind power generation, load and the conventional units. The scenario-reduction methodology is combined to reduce the large scenario set to a simpler one, then the probability statistics on these scenarios is given in order to obtain the probability density of the system power difference, and the expected energy not supplied (EENS) and expected wind waste risk (EWWR) are presented. The reserve capacity is determined by the two aspects, which are the reliability shown by EENS and EWWR, and the economy of reserve capacity cost. Finally, simulations on a ten-unit system are given to demonstrate the method is effective to reduce the cost of reserve and the abandoned wind power in the context of system reliability.
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Díaz, Antonio, Gonzalo García-Donato, and Andrés Mora-Valencia. "Quantifying Risk in Traditional Energy and Sustainable Investments." Sustainability 11, no. 3 (January 30, 2019): 720. http://dx.doi.org/10.3390/su11030720.
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These days we are witnessing a deep change in the characteristics of the type of energy that our economies are supplied with. A clear trend is that sustainable and green energies are decisively replacing traditional fossil fuel-based sources of energy. For various reasons, this fundamental change implies an increasing risk in investments on portfolios heavily based on traditional energy industries. What is less known, is that these industries have returns that show a very low correlation with sustainable fossil fuel-free stock portfolios making them an appealing tool for portfolio managers to design properly diversified investments. In this study we examine this and related phenomena proposing statistical methods to implement the expected shortfall (ES), the challenging risk measure recently adopted by the financial regulator. We obtain evidence that a newly proposed backtesting procedure for the ES based on multinomial tests is an adequate and simple method to validate these risk measures when applied to a highly volatile stock index. Backtesting results of the ES show that flexible heavy-tailed distribution α–stable performs well for modelling the loss distribution. These results are even improved when the variances of fossil fuel price returns are included as external regressors in the GARCH model variance equation. In this case, the ES computed from the four considered loss distributions perform properly.
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Jaszczur, Marek, Qusay Hassan, Haidar N. Al-Anbagi, and Patryk Palej. "A numerical analysis of a HYBRID PV+WT power system." E3S Web of Conferences 128 (2019): 05001. http://dx.doi.org/10.1051/e3sconf/201912805001.
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The increase in global energy consumption and the expected exhaustion of traditional energy sources, especially in the last century, led to an increased search for alternative sources of energy.The use of renewable energy sources has become extremely important to reduce dependence on fossil fuels. Due to the stochastic nature of the renewable energy sources such as the wind speed fluctuation and the intensity of solar radiation the stable operation of the systems base single renewable source can be problematic. But the using two or more of these sources results in higher stability than relying on a single source. For this reason, hybrid renewable energy systems have become an attractive solution in thefield of renewable energy. A hybrid energy system is a combination of two or more renewable energy sources that can enhance each another to increase the reliability of the supplied energy. The objective of this paper is investigation about the energy supplying improvement and the energy efficiency utilisation by hybridisation using two renewable energy resources: wind energy and solar energy with respect two different optimisation objectives: economical to reduce the net present cost and ecological to reduce CO2 emissions. Presented system has been implemented to supply a single household with an electric load.
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Bermeo, I., L. Matute, E. Barragán-Escandón, X. Serrano-Guerrero, and E. Zalamea-León. "Technical and economic feasibility study of a solar plant on a commercial surface in Azogues, Ecuador." Renewable Energy and Power Quality Journal 19 (September 2021): 177–83. http://dx.doi.org/10.24084/repqj19.250.
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The submitted paper deals with the shopping mall project that will be supplied with solar power. The selected location was "La Playa Store" shopping center located in the city of Azogues, south of Ecuador. This type of building has at least two characteristics worth studying i) the available surface on the roof, ii) the characteristics of the energy demand curve. This evaluation process establishes the energy requirement of the installation; that is, the energy potential available depending on the surface of its roof, to design a solar plant according to international standards and local ARCONEL 003/18 regulations. The tools used for the involving simulation were the Lumion software, an IFC file created and imported into the Solarius Pv energy simulator, a software specialized in the design of photovoltaic systems. The designed photovoltaic system has a projected annual energy generation of 9,3695.26 kWh; an installed price per watt of $1.1 with viable results at the end of the fifth year of implementation with an IRR of 7.33% and NPV of $390.51. As this is a commercial facility, a constant and flat consumption throughout the day is expected, so implementing solar energy would reduce the actual power requirements by 32.63%
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Wanapinit, Natapon, and Jessica Thomsen. "Synergies between Renewable Energy and Flexibility Investments: A Case of a Medium-Sized Industry." Energies 14, no. 22 (November 18, 2021): 7753. http://dx.doi.org/10.3390/en14227753.
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Climate and energy policies are tools used to steer the development of a sustainable economy supplied by equally sustainable energy systems. End-users should plan their investments accounting for future policies, such as incentives for system-oriented consumption, emission prices and hydrogen economy, to ensure long-term competitiveness. In this work, the utilization of variable renewable energy and flexibility potentials in a case study of an aggregate industry is investigated. An energy concept considering PV and battery expansion, flexible production, fuel cell electric trucks (FCEV) and hydrogen production is proposed, and analysed under expected techno-economic conditions and policies of 2030 using an energy system optimization model. Under this concept, total costs and emissions are reduced by 14% and 70%, respectively, compared to the business-as-usual system. The main benefit of PV investment is the lowered electricity procurement. Flexibility from schedulable manufacturing and hydrogen production increases not only the self-consumption of PV generation from 51% to 80% but also the optimal PV capacity by 41%. Despite the expected cost reduction and efficiency improvement, FCEV is still not competitive to diesel trucks due to higher investment and fuel prices, i.e., its adoption increases the costs by 8%. However, this is resolved when hydrogen can be produced from own surplus electricity generation. Our findings reveal synergistic effects between different potentials and the importance of enabling local business models, e.g., regional hydrogen production and storage services. The SWOT analysis of the proposed concept shows that the pursuit of sustainability via new technologies entails new opportunities and risks. Lastly, end-users and policymakers are advised to plan their investments and supports towards integration of multiple application, consumption sectors and infrastructure.
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Baetens, Jens, Jeroen D. M. De Kooning, Greet Van Eetvelde, and Lieven Vandevelde. "A Two-Stage Stochastic Optimisation Methodology for the Operation of a Chlor-Alkali Electrolyser under Variable DAM and FCR Market Prices." Energies 13, no. 21 (October 30, 2020): 5675. http://dx.doi.org/10.3390/en13215675.
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The increased penetration of renewable energy sources in the electrical grid raises the need for more power system flexibility. One of the high potential groups to provide such flexibility is the industry. Incentives to do so are provided by variable pricing and remuneration of supplied ancillary services. The operational flexibility of a chlor-alkali electrolysis process shows opportunities in the current energy and ancillary services markets. A co-optimisation of operating the chlor-alkali process under an hourly variable priced electricity sourcing strategy and the delivery of Frequency Containment Reserve (FCR) is the core of this work. A short term price prediction for the Day-Ahead Market (DAM) and FCR market as input for a deterministic optimisation shows good results under standard DAM price patterns, but leaves room for improvement in case of price fluctuations, e.g., as caused by Renewable Energy Sources (RES). A two-stage stochastic optimisation is considered to cope with the uncertainties introduced by the exogenous parameters. An improvement of the stochastic solution over the deterministic Expected Value (EV) solution is shown.
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Oko, COC, E. O. Diemuodeke, E. O. Omunakwe, and E. Nnamdi. "Design and Economic Analysis of a Photovoltaic System: A Case Study." International Journal of Renewable Energy Development 1, no. 3 (October 30, 2012): 65. http://dx.doi.org/10.14710/ijred.1.3.65-73.
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This paper presents the design analysis of a photovoltaic (PV) system to power the CAD/CAM Laboratory at the Department of Mechanical Engineering, University of Port Harcourt. Life cycle cost and break-even point analyses are also carried out to assess the economic viability of the system. The unit cost of electricity for the designed PV system is high compared to the current unit cost of the municipally supplied electricity, but will be competitive with lowering cost of PV system components and favourable government policies on renewable energy. The approach and data provided are useful for designing solar systems in the area. The automated MS Excel spreadsheet developed could be used for the design and economic analyses of PV system in any other geographical region once the input data are sorted. Since about 90% of businesses in Nigeria currently own diesel generators, it is expected that future work should be devoted to the optimum combination of PV-Battery-Diesel system in electricity generation for optimum economic benefits to the country. Keywords: photovoltaic system design, renewable energy technology, solar energy economics
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XU, SUSAN H. "A STOCHASTIC SINGLE-PERIOD INVENTORY SYSTEM WITH RANDOM YIELDS AND QUALITIES." International Journal of Reliability, Quality and Safety Engineering 01, no. 04 (December 1994): 475–84. http://dx.doi.org/10.1142/s0218539394000337.
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This paper considers a single-period inventory model where a commodity may be ordered from one of several suppliers with various yields and qualities. Two variations of this model are investigated. First it is assumed that replenishment quantities (yields) follow variability orderings (defined in Sec. 2) and shown that, if the purchasing, holding, and shortage costs are increasing and convex, and the the cost of quality loss is negligible, then ordering from the supplier with the smallest yield variability minimizes the expected cost of the period. In the second variations it is assumed that the replenishment quantities and qualities from the suppliers follow variability orderings, where the quality of an item is represented by a measurement z. An item sold with measurement z is subject to a quality loss l(z), where l(z) is a convex function taking the minimum at the target measurement. It is shown that if the purchasing, holding, and shortage cost functions are linear and increasing, then selecting the supplier with the smallest yield and quality variabilities minimizes the expected cost of the period.
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Hashim, YB Dato' Murad. "Energy Development in Malaysia." Energy Exploration & Exploitation 6, no. 4-5 (September 1988): 336–41. http://dx.doi.org/10.1177/014459878800600407.
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The Malaysian governments Four Fuel Energy Policy is concerned with security of supply and the need to meet economic development targets through greater use of natural gas, hydropower and with imported coal. Gas reserves are 52 trillion cu. ft. and hydropower potential 29,000MW. Coal is included because of the enormous supplies available worldwide. Indigenous natural gas consumption is expected to grow at 9% p.a. till the year 2000 and to account for 40% of the total energy consumption. The Peninsula Gas Utilisation project will reduce the use of oil in electricity generation, provide it for steel manufacture and deliver gas to the domestic market. Natural gas will be used increasingly in transportation and for petrochemicals, excess production is destined for export.
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Bapin, Bagheri, and Zarikas. "Optimal Allocation of Spinning Reserves in Interconnected Energy Systems with Demand Response Using a Bivariate Wind Prediction Model." Energies 12, no. 20 (October 9, 2019): 3816. http://dx.doi.org/10.3390/en12203816.
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The proposed study presents a novel probabilistic method for optimal allocation of spinning reserves taking into consideration load, wind and solar forecast errors, inter-zonal spinning reserve trading, and demand response provided by consumers as a single framework. The model considers the system contingencies due to random generator outages as well as the uncertainties caused by load and renewable energy forecast errors. The study utilizes a novel approach to model wind speed and its direction using the bivariate parametric model. The proposed model is applied to the IEEE two-area reliability test system (RTS) to analyze the influence of inter-zonal power generation and demand response (DR) on the adequacy and economic efficiency of energy systems. In addition, the study analyzed the effect of the bivariate wind prediction model on obtained results. The results demonstrate that the presence of inter-zonal capacity in ancillary service markets reduce the total expected energy not supplied (EENS) by 81.66%, while inclusion of a DR program results in an additional 1.76% reduction of EENS. Finally, the proposed bivariate wind prediction model showed a 0.27% reduction in spinning reserve requirements, compared to the univariate model.
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Sun, Ruijuan, Gayan Abeynayake, Jun Liang, and Kewen Wang. "Reliability and Economic Evaluation of Offshore Wind Power DC Collection Systems." Energies 14, no. 10 (May 18, 2021): 2922. http://dx.doi.org/10.3390/en14102922.
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One key directive to realize the global transition towards net-zero emission goals is to integrate more renewable energy resources into the generation mix. Due to higher and more consistent wind speeds, offshore wind farms (OWFs) have the potential to generate more energy at a steadier rate than their onshore counterpart. However, at the collection system level, all the OWFs use alternating current (AC) technology at present. Nonetheless, with an increasing capacity of the single wind turbine (WT) and larger distances to the shore, the use of direct current (DC) technology at the collection system level is beneficial. To select a suitable DC collection system topology, this paper proposes a comprehensive analytical reliability evaluation method, based on the Universal Generating Function technique, together with associated economic factors. Four candidates DC collection system options were evaluated with different WT capacities for a 400 MW OWF. The availability indices such as Generation Ratio Availability and Expected Energy Not Supplied were used to assess their reliability levels. The results show that the radial topology with a single platform DC/DC converter is more reliable and economical than the other candidate options.
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Veeramsetty, Venkataramana, Venkaiah Chintham, and Vinod Kumar D.M. "Locational marginal price computation in radial distribution system using Self Adaptive Levy Flight based JAYA Algorithm and game theory." International Journal of Emerging Electric Power Systems 22, no. 2 (February 22, 2021): 215–31. http://dx.doi.org/10.1515/ijeeps-2020-0236.
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Abstract This study presents a computational approach to compute locational marginal price (LMP) at distributed generation (DG) buses in an electric power distribution system using self-adaptive levy flight based JAYA algorithm and proportional nucleolus theory (PNT). This method provides financial incentive to DG owners based on their contribution in reliability improvement, loss and emission reduction. In this study expected energy not supplied (EENS) is used for measuring the reliability of a given radial distribution network. This method is implemented on 38 bus distribution system under MATLAB environment to compute LMP values at each DG as per its contribution towards reliability improvement, loss reduction and emission reduction. It is found from the study that reliability has been improved, losses and emissions of system were reduced by providing proper financial incentives to DG owners. The proposed method can be utilized by a distribution company (DISCO) to operate network optimally and to estimate state of network.
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Liu, Jin. "China's demand for natural gas: drivers and prospects." APPEA Journal 52, no. 2 (2012): 645. http://dx.doi.org/10.1071/aj11059.
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Sustained economic growth in China has triggered a surge of energy and mineral consumption and imports, including natural gas. This study presents recent trends in China’s demand for natural gas in a global context and discusses its drivers and prospects. In the past decade, drivers of China’s demand for natural gas are mainly associated with its rapid economic growth, path of industrialisation and urbanisation. With more than 1.3 billion people and a rapidly rising income level, China’s demand for energy has surged. It is increasingly difficult for domestic production capacity to supply all of this demand, especially when China’s limited domestic reserves are considered. The prospect of potential growth in natural gas consumption and imports is expected not only due to China’s economic growth, but also a policy imperative (e.g. the 12th Five Year Plan) to increase the share of clean energy sources such as gas and efficient fuels in the energy supply mix, as well as improving energy intensity and other factors that will influence energy sector outcomes. It also establishes that LNG, in addition to pipeline supplied gas, is likely to be an important source of energy in China in the coming decade; therefore, due to rebalancing its energy mix and increasing the share of non-coal energy sources in China’s energy market, it is anticipated that China will be more dependent on overseas supply of natural gas to fill the gap between domestic production and consumption.
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Amewornu, Ernestina M., and Nnamdi I. Nwulu. "Assessing the impact of demand response programs on the reliability of the Ghanian distribution network." PLOS ONE 16, no. 3 (March 11, 2021): e0248012. http://dx.doi.org/10.1371/journal.pone.0248012.
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The balancing of supplied energy to energy demand is often very challenging due to unstable power supply and demand load. This challenge causes the level of performance of distribution networks to be lower than expected. Research has however, shown the role of demand response (DR) on the performance of power networks. This work investigates the influence of DR, in the presence of incorporated renewable energy, on technical loss reduction, reliability, environment, energy saved and incentives paid to consumers with the help of PSAT and AIMMS software. Results from simulation have shown that the introduction of renewable energy into a Ghanaian distribution network coupled with implementing the proposed DR improves total energy supply by 9.8% at a corresponding operation cost reduction of 72.79%. The GHG and technical loss reduced by 27.26% and 10.09% respectively. The total energy saving is about 105kWh and 5,394.86kWh, for domestic and commercial loading profiles, respectively. Incentives received by consumers range between 45.14% and 58.55% more than that enjoyed, without renewable energy, by domestic and commercial consumers. The utility benefit also increased by 76.96% and 67.31% for domestic and commercial loads than that without renewable energy. Network reliability improves with implementation of DR. However, the reliability of a grid-connected network is better with a diesel generator only than with the integration of renewable energy. The power distribution companies, therefore, need to consider the implementation of incentive-based demand response program.
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Mathieu, Robert D. "Accretion onto Pre-Main Sequence Binary Stars: The Circumstellar Environment." Symposium - International Astronomical Union 200 (2001): 419–28. http://dx.doi.org/10.1017/s0074180900225497.
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Observations show that mass accretion can occur at the surfaces of stars in young binaries of all separations. Given that resonant torques have been expected to clear gaps and dam the inward flow of material from circumbinary disks, this result begs the question of how mass accretion is supplied in binary systems. In this paper we address this question in the context of close binaries. Spectral energy distributions indicate that dynamical clearing is not complete for close binaries having massive circumbinary disks. High-resolution infrared spectra of CO rotational and ro-vibrational lines have also detected small amounts of gas which can be located in the region of dynamical clearing. Thus we have signatures of matter from the circumbinary environment through the predicted gap region to the stellar surfaces. We suggest that accretion streams may supply both dynamically cleared regions and circumstellar disks.
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la Cour Jansen, J., G. H. Kristensen, and K. D. Laursen. "Activated Sludge Nitrification in Temperate Climate." Water Science and Technology 25, no. 4-5 (February 1, 1992): 177–84. http://dx.doi.org/10.2166/wst.1992.0493.
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In Denmark winter temperature of the wastewater is typically 5-10°C, and ammonia concentrations below 1-4 mg/l are normal discharge limits under these conditions. Special attention is needed in design and operation of treatment plants in order to fulfill such limits. Based on a simple energy balance a steady-state temperature model is developed and verified at full scale treatment plants. The model enables a good estimate of expected winter temperatures in the design phase. Deep tanks and good protection against wind exposure are shown to be attractive means to avoid a too low process temperature during winter periods. Successful winter nitrification can be obtained if the plant operator is supplied with tools to identify arising problems. A procedure to predict if the actual plant nitrification capacity is approaching the necessary capacity based on the load is described and tested.
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Dalby, J. A., J. M. Forbes, M. A. Varley, and S. Jagger. "Diet Selection of Weaned Piglets - Is a Training Period Necessary?" Proceedings of the British Society of Animal Production (1972) 1994 (March 1994): 35. http://dx.doi.org/10.1017/s0308229600025861.
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The requirements of a weaned piglet are expected to change systematically over the period 6kg-25kg. Commonly during this time animals will be offered two diets. However, initially on each diet the animal may be restricted because it's protein requirements are in excess of that supplied by the diet. Then latterly, amino acids may be oversupplied requiring deamination of the excess by the pig. This is a costly process, in terms of the energy required by the pig and commercially, in terms of food protein costs. This system also does not take into account differing individual requirements within a group of pigs due to genotype, sex, maturity and stage of growth. As a result potential benefits are to be obtained if weaned piglets can be shown to choose an adequate diet, meeting their individual requirements, when given a choice of feeds.
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Vargas-Jaramillo, Jose, Jhon Montanez-Barrera, Michael von Spakovsky, Lamine Mili, and Sergio Cano-Andrade. "Effects of Producer and Transmission Reliability on the Sustainability Assessment of Power System Networks." Energies 12, no. 3 (February 10, 2019): 546. http://dx.doi.org/10.3390/en12030546.
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Details are presented of the development and incorporation of a generation and transmission reliability approach in an upper-level sustainability assessment framework for power system planning. This application represents a quasi-stationary, multiobjective optimization problem with nonlinear constraints, load uncertainties, stochastic effects for renewable energy producers, and the propagation of uncertainties along the transmission lines. The Expected Energy Not Supplied (EENS) accounts for generation and transmission reliability and is based on a probabilistic as opposed to deterministic approach. The optimization is developed for three scenarios. The first excludes uncertainties in the load demand, while the second includes them. The third scenario accounts not only for these uncertainties, but also for the stochastic effects related to wind and photovoltaic producers. The sustainability-reliability approach is applied to the standard IEEE Reliability Test System. Results show that using a Mixture of Normals Approximation (MONA) for the EENS formulation makes the reliability analysis simpler, as well as possible within a large-scale optimization. In addition, results show that the inclusion of renewable energy producers has some positive impact on the optimal synthesis/design of power networks under sustainability considerations. Also shown is the negative impact of renewable energy producers on the reliability of the power network.
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Zwierzyński, Adam Jan, Wojciech Teper, Rafał Wiśniowski, Andrzej Gonet, Tomasz Buratowski, Tadeusz Uhl, and Karol Seweryn. "Feasibility Study of Low Mass and Low Energy Consumption Drilling Devices for Future Space (Mining Surveying) Missions." Energies 14, no. 16 (August 15, 2021): 5005. http://dx.doi.org/10.3390/en14165005.
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The global climate crisis forces the search for new ecological sources of energy and mining methods. Space mining can solve those problems, but, first, wide geological surveying space missions using drilling methods are necessary. Additionally, drilling methods will be important in geological, life searching, geoengineering, and many other studies of extraterrestrial objects. Space is becoming a new area of possible drilling applications. Designing future space drilling missions requires adapting drilling technologies, not only to the conditions of the space environment, but also to the economic and technological realities of the space industry. The possibility of constructing low mass coring devices with energy consumption below 100 W was investigated in this paper. Minimization of energy consumption and mass of a coring is essential for the device to be used in space missions, when lander instruments supplied by low power electric battery are expected to work reliably and the launch cost (depending of mass) at an economically acceptable level. Some similar devices investigated for the future space missions are known from papers listed in the references. To answer whether or not it is possible to build such devices, the authors performed initial drillability tests. The obtained results are presented in this paper.
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Arias-González, Felipe, Alejandra Rodríguez-Contreras, Miquel Punset, José María Manero, Óscar Barro, Mónica Fernández-Arias, Fernando Lusquiños, Francisco Javier Gil, and Juan Pou. "In-Situ Laser Directed Energy Deposition of Biomedical Ti-Nb and Ti-Zr-Nb Alloys from Elemental Powders." Metals 11, no. 8 (July 28, 2021): 1205. http://dx.doi.org/10.3390/met11081205.
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In order to achieve the required properties of titanium implants, more resources and research are needed to turn into reality the dream of developing the perfect implant material. The objective of this study was to evaluate the viability of the Laser Directed Energy Deposition to produce biomedical Ti-Nb and Ti-Zr-Nb alloys from elemental powders (Ti, Nb and Zr). The Laser Directed Energy Deposition is an additive manufacturing process used to build a component by delivering energy and material simultaneously. The material is supplied in the form of particles or wire and a laser beam is employed to melt material that is selectively deposited on a specified surface, where it solidifies. Samples with different compositions are characterized to analyze their morphology, microstructure, constituent phases, mechanical properties, corrosion resistance and cytocompatibility. Laser-deposited Ti-Nb and Ti-Zr-Nb alloys show no relevant defects, such as pores or cracks. Titanium alloys with lower elastic modulus and a significantly higher hardness than Ti grade 2 were generated, therefore a better wear resistance could be expected from them. Moreover, their corrosion resistance is excellent due to the formation of a stable passive protective oxide film on the surface of the material; in addition, they also possess outstanding cytocompatibility.
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Renno, Carlo, Alessandro Perone, Diana D’Agostino, and Francesco Minichiello. "Experimental and Economic Analysis of a Concentrating Photovoltaic System Applied to Users of Increasing Size." Energies 14, no. 16 (August 13, 2021): 4968. http://dx.doi.org/10.3390/en14164968.
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The costs of concentrating photovoltaic (CPV) and concentrating photovoltaic and thermal (CPV/T) systems are highly reduced in the last years because of their increasing diffusion. The unit power cost also depends on the plant size. Hence, the main aim of this paper is to analyze the feasibility of a CPV/T system adopted for users with increasing sizes located in Salerno (Italy): the house, the hotel, and the food industry. An experimental model was developed for an accurate evaluation of the electrical and thermal powers supplied by the CPV/T system when direct normal irradiation (DNI) and environmental temperature vary. A modular configuration of a line-focus CPV/T system was sized to match the electrical and thermal loads of each user. The current economic results, together with a forecast till the year 2025, were discussed. In 2025, for the same CPV system adopted for the domestic user, the net present value (NPVs) are expected to increase by 6.7% and 13% in pessimistic and optimistic scenarios, respectively, with reductions of its discounted payback period (DPBP) of 16% and 30%. For the same CPV systems adopted for the other two users, the NPVs are expected to increase by about 4.2% and 8.4% in pessimistic and optimistic scenarios, respectively, with decreases of its DPBP of 14% and 27%.
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Kaur, Amneet, and Harpreet Kaur. "A REVIEW ON A HYBRID APPROACH USING MOBILE SINK AND FUZZY LOGIC FOR REGION BASED CLUSTERING IN WSN." INTERNATIONAL JOURNAL OF COMPUTERS & TECHNOLOGY 16, no. 2 (March 22, 2017): 7586–90. http://dx.doi.org/10.24297/ijct.v16i2.5999.
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A Wireless Sensor Network or WSN is supposed to be made up of a large number of sensors and at least one base station. The sensors are autonomous small devices with several constraints like the battery power, computation capacity, communication range and memory. They also are supplied with transceivers to gather information from its environment and pass it on up to a certain base station, where the measured parameters can be stored and available for the end user. In most cases, the sensors forming these networks are deployed randomly and left unattended to and are expected to perform their mission properly and efficiently. As a result of this random deployment, the WSN has usually varying degrees of node density along its area. Sensor networks are also energy constrained since the individual sensors, which the network is formed with, are extremely energy-constrained as well. Wireless sensor networks have become increasingly popular due to their wide range of application. Clustering sensor nodes organizing them hierarchically have proven to be an effective method to provide better data aggregation and scalability for the sensor network while conserving limited energy. Minimizing the energy consumption of a wireless sensor network application is crucial for effective realization of the intended application in terms of cost, lifetime, and functionality. However, the minimizing task is hardly possible as no overall energy cost function is available for optimization.
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Litwin, Wojciech, Wojciech Leśniewski, and Jakub Kowalski. "Energy Efficient and Environmentally Friendly Hybrid Conversion of Inland Passenger Vessel." Polish Maritime Research 24, no. 4 (December 20, 2017): 77–84. http://dx.doi.org/10.1515/pomr-2017-0138.
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Abstract The development and growing availability of modern technologies, along with more and more severe environment protection standards which frequently take a form of legal regulations, are the reason why attempts are made to find a quiet and economical propulsion system not only for newly built watercraft units, but also for modernised ones. Correct selection of the propulsion and supply system for a given vessel affects significantly not only the energy efficiency of the propulsions system but also the environment - as this selection is crucial for the noise and exhaust emission levels. The paper presents results of experimental examination of ship power demand performed on a historic passenger ship of 25 m in length. Two variants, referred to as serial and parallel hybrid propulsion systems, were examined with respect to the maximum length of the single-day route covered by the ship. The recorded power demands and environmental impact were compared with those characteristic for the already installed conventional propulsion system. Taking into account a high safety level expected to be ensured on a passenger ship, the serial hybrid system was based on two electric motors working in parallel and supplied from two separate sets of batteries. This solution ensures higher reliability, along with relatively high energy efficiency. The results of the performed examination have revealed that the serial propulsion system is the least harmful to the environment, but its investment cost is the highest. In this context, the optimum solution for the ship owner seems to be a parallel hybrid system of diesel-electric type
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Alhajeri, Hamad M., Abdulrahman Almutairi, Abdulrahman Alenezi, and Faisal Alshammari. "Energy Demand in the State of Kuwait During the Covid-19 Pandemic: Technical, Economic, and Environmental Perspectives." Energies 13, no. 17 (August 24, 2020): 4370. http://dx.doi.org/10.3390/en13174370.
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The present paper reports the impact of the Covid-19 pandemic on the electricity peak load and power generation in the State of Kuwait during the partial and full curfews imposed in March, April and May 2020 using historic data measured data and the predictions provided by a statistical genetic algorithm model. A quantitative assessment is made of the economic and environmental impacts caused by partial and full lockdowns. Comparison of measured peak demand for 2019 and 2020 with predicted peak demand for 2020 has: (i) enabled an accurate evaluation of residential energy consumption in the state of Kuwait at nearly 18 MWh yearly the highest energy consumption per capita in the world, (ii) shown that the imposition of the curfews to reduce the spread of COVID-19 caused a fall in the demand for electrical power of 17.6% compared with the expected demand and (iii) quantified the reduction in CO2, NOx and CO pollutant emissions produced by power plants due to less fuel being consumed. A mathematical model has been developed to predict the peak electric load in the national grid according to climatic data supplied by the Meteorological Department of Civil Aviation of Kuwait and National Control Center (NCC).
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Yanine, Franco Fernando, Enzo E. Sauma, and Felisa Margarita Cordova. "An Exergy and Homeostatic Control Approach to Sustainable Grid-Connected Microgrids without Energy Storage." Applied Mechanics and Materials 472 (January 2014): 1027–31. http://dx.doi.org/10.4028/www.scientific.net/amm.472.1027.
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This paper approaches the microgrid concept from a systemic and cybernetics viewpoint, as a viable sustainable energy system (SES) for supplying electricity and heat to small, rural communities in Chile. As such the microgrid may be viewed as a complex adaptive system (CAS) when connected to the grid and operating without energy storage, only with the grid as back-up power source. From an exergy and homeostatic control (HC) standpoint, one may analyze the microgrid as a socio-technical CAS when it is coupled with a set of homes and also connected to the grid; capable of supplying close to 80% of the daily residential consumer needs on average. Thus, under these conditions homes may draw inexpensive renewable electricity and heat from the microgrid if they are thrifty and efficient in their energy consumption, and they may also consume from the utility grid, yet at an expensive price. Based on this an exergy and HC approach is proposed to develop such SES for rural and remote communities in Chile and South America, aiming to enhance energy efficiency (EE) and energy sustainability (ES). Under this scheme, renewable power (RP) being a scarce resource that must be managed efficientlyis supplied only to homes which comply with a specific criterion in an effort to curtail demand to ensure ES overtime. Simulation shows as expected that indeed certain criteria produce much better results than others in incentivizing thrifty, efficient energy consumption for small-size communities without the need for expensive and sometimes polluting and forbidden energy storage systems.
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Tanner, C. C., and R. H. Kadlec. "Oxygen flux implications of observed nitrogen removal rates in subsurface-flow treatment wetlands." Water Science and Technology 48, no. 5 (September 1, 2003): 191–98. http://dx.doi.org/10.2166/wst.2003.0317.
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Nitrification, an oxygen-requiring microbial process, is generally considered the rate-limiting step for N removal in subsurface-flow constructed wetlands treating organic wastewaters. We used a simplified model of sequential N transformations and sinks to infer required rates of oxygen supply at 5 stages along experimental wetland mesocosms supplied with four different organic wastewaters with contrasting ratios of COD: N and forms of N. Mass balances of water-borne organic, ammoniacal and nitrate N, and plant and sediment N uptake showed average net rates of N mineralisation ranging from 0.22-0.53 g m-2 d-1, nitrification 0.56-2.15 g m-2 d-1, denitrification 0.47-1.99 g m-2 d-1 (60-84% of measured N removal) and plant assimilation 0.28-0.47 g m-2 d-1. The nitrogenous oxygen demand (NOD) required to support the observed nitrification rates alone was high compared to expected fluxes from surficial and plant-mediated oxygen transfer. In the presence of high levels of degradable organic matter (COD removal rates up to 66 g m-2 d-1), heterotrophs with significantly higher oxygen affinities and energy yields are expected to out-compete nitrifiers for available oxygen. Problems with commonly held assumptions on the nature of coupled nitrification-denitrification in treatment wetlands are discussed.
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Nomura, Mariko, Ken Ohsuga, and Chris Done. "Line-driven disc wind in near-Eddington active galactic nuclei: decrease of mass accretion rate due to powerful outflow." Monthly Notices of the Royal Astronomical Society 494, no. 3 (April 11, 2020): 3616–26. http://dx.doi.org/10.1093/mnras/staa948.
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ABSTRACT Based on recent X-ray observations, ultrafast outflows from supermassive black holes are expected to have enough energy to dramatically affect their host galaxy but their launch and acceleration mechanisms are not well understood. We perform two-dimensional radiation hydrodynamics simulations of UV line-driven disc winds in order to calculate the mass-loss rates and kinetic power in these models. We develop a new iterative technique that reduces the mass accretion rate through the inner disc in response to the wind mass-loss. This makes the inner disc less UV bright, reducing the wind power compared to previous simulations which assumed a constant accretion rate with radius. The line-driven winds in our simulations are still extremely powerful, with around half the supplied mass accretion rate being ejected in the wind for black holes with mass 108–$10^{10}\, \mathrm{ M}_\odot$ accreting at L/LEdd = 0.5–0.9. Our results open up the way for estimating the growth rate of supermassive black hole and evaluating the kinetic energy ejected into the interstellar medium (active galactic nuclei feedback) based on a physical model of line-driven disc winds.
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Borzea, Claudia, Iulian Vlăducă, Dan Ionescu, Valentin Petrescu, Filip Niculescu, Cristian Nechifor, Gabriel Vătăşelu, and Mihai Hanek. "Compressed Air Energy Storage Installation for Renewable Energy Generation." E3S Web of Conferences 112 (2019): 02010. http://dx.doi.org/10.1051/e3sconf/201911202010.
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Compressed Air Energy Storage (CAES) installations are used for storing electrical power, under the form of potential energy from compressed air. The heat generated during compression can be stored to improve the efficiency of compression-expansion cycle. The solution presented consists of a 100 kW screw compressor driven by a 110 kW asynchronous three-phase motor. The compressor supplies air into vessels which store it until a high electrical energy demand arises. At that time, the compressed air is released into a 132 kW screw expander whose shaft spins a 132 kW asynchronous generator, producing electric power and supplying it into the electrical grid. Before expansion, the air must be preheated in order to avoid the freezing of expansion equipment. If the heat generated during compression is used for air preheating before expansion, the process is adiabatic. A demonstrative model of the installation is currently being developed, with the expander part being completed so far. The maximum power to be produced was calculated to be around 100 kW. During expander commissioning tests with air supply from a 250 kW high pressure compressor, a maximum generated power of 49.7 kW was attained, expected to be higher when releasing air from the reservoirs.
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Eslami, R., S. H. H. Sadeghi, and H. Askarian Abyaneh. "A Probabilistic Approach for the Evaluation of Fault Detection Schemes in Microgrids." Engineering, Technology & Applied Science Research 7, no. 5 (October 19, 2017): 1967–73. http://dx.doi.org/10.48084/etasr.1472.
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An important challenge in protection of a microgrid is the process of fault detection, considering the uncertainties in its topologies. Equally important is the evaluation of proposed methods as their incorrect performances could result in unreasonable power outages. In this paper, a new fault detection and characterization method is introduced and evaluated subject to the uncertainties of network topologies. The features of three-phase components together with the positive, negative and zero sequences of current and voltage waveforms are derived to detect the occurrence of a fault, its location, type and the engaged phases. The proposed method is independent of the microgrid topology. To evaluate the performance of the proposed method in various network topologies, a Monte Carlo scheme is developed. This is done by computing the expected energy not-supplied reliability index and the percentage of successful performance of the fault detection. Simulation results show that the proposed method can detect faults in various microgrid topologies with a very high degree of accuracy.
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Bargiacchi, Eleonora, Nils Thonemann, Jutta Geldermann, Marco Antonelli, and Umberto Desideri. "Life Cycle Assessment of Synthetic Natural Gas Production from Different CO2 Sources: A Cradle-to-Gate Study." Energies 13, no. 17 (September 3, 2020): 4579. http://dx.doi.org/10.3390/en13174579.
Full textAbstract:
Fuel production from hydrogen and carbon dioxide is considered an attractive solution as long-term storage of electric energy and as temporary storage of carbon dioxide. A large variety of CO2 sources are suitable for Carbon Capture Utilization (CCU), and the process energy intensity depends on the separation technology and, ultimately, on the CO2 concentration in the flue gas. Since the carbon capture process emits more CO2 than the expected demand for CO2 utilization, the most sustainable CO2 sources must be selected. This work aimed at modeling a Power-to-Gas (PtG) plant and assessing the most suitable carbon sources from a Life Cycle Assessment (LCA) perspective. The PtG plant was supplied by electricity from a 2030 scenario for Italian electricity generation. The plant impacts were assessed using data from the ecoinvent database version 3.5, for different CO2 sources (e.g., air, cement, iron, and steel plants). A detailed discussion on how to handle multi-functionality was also carried out. The results showed that capturing CO2 from hydrogen production plants and integrated pulp and paper mills led to the lowest impacts concerning all investigated indicators. The choice of how to handle multi-functional activities had a crucial impact on the assessment.