scholarly journals Possibilities of Biogas in Urban Context

2020 ◽  
Vol 15 (3) ◽  
pp. 191-199
Author(s):  
Srijana Koirala

Increasing population and rapid development in the planet earth have resulted in increasing demand of energy sources. Developed countries have adopted renewable sources in their policy for a sustainable future but, developing countries like Nepal are still lagging behind. Petroleum gas is used by all the city dwellers which is imported from neighboring countries and is not sustainable for a long term. Rapid urban growth has brought solid waste management and energy demand as a great challenge. Production of energy through biogas can help in management of bio-degradable waste as well as fulfill energy demands. This paper highlights study of large-scale biogas plant in and outside Nepal and explains how they have helped in managing waste, fulfilling energy demands and made positive impact in the community. This paper also suggests on possibilities of biogas as an alternative energy in developing scenario of Nepal.

Author(s):  
Andrei Mircea Bolboaca

Covering the energy demands under environmental protection and satisfying economic and social restrictions, together with decreasing polluting emissions, are impetuous necessities, considering that over half of the pollutant emissions released in the environment are the effect of the processes of electricity and heat production from the classic thermoelectric powerplant. Increasing energy efficiency and intensifying the use of alternative resources are key objectives of global policy. In this context, a range of new energy technologies has been developed, based on alternative energy conversion systems, which have recently been used more and more often for the simultaneous production of electricity and heat. An intensification of the use of combined energy production correlated with the tendency towards the use of clean energy resources can be helpful in achieving the global objectives of increasing fuel diversity and ensuring energy demand. The chapter aims at describing the fuel cell technology, in particular those of the SOFC type, used in the CHP for stationary applications.


Author(s):  
Satoshi Gamou ◽  
Koichi Ito ◽  
Ryohei Yokoyama

The relationships between unit numbers and capacities to be installed for microturbine cogeneration systems are analyzed from an economic viewpoint. In analyzing, an optimization approach is adopted. Namely, unit numbers and capacities are determined together with maximum contract demands of utilities such as electricity and natural gas so as to minimize the annual total cost in consideration of annual operational strategies corresponding to seasonal and hourly energy demand requirements. This optimization problem is formulated as a large-scale mixed-integer linear programming one. The suboptimal solution of this problem is obtained efficiently by solving several small-scale subproblems. Through numerical studies carried out on systems installed in hotels by changing the electrical generating/exhaust heat recovery efficiencies, the initial capital cost of the microturbine cogeneration unit and maximum energy demands as parameters, the influence of the parameters on the optimal numbers and capacities of the microturbine cogeneration units is clarified.


2011 ◽  
Vol 33 (4) ◽  
pp. 315 ◽  
Author(s):  
Barrie Pittock

Desert/remote Australia is blessed with abundant natural energy resources from solar, geothermal and other renewable sources. If these were harnessed and connected appropriately desert/remote Australia could be not only energy self-sufficient but a net exporter. Generation of abundant, clean energy can also attract energy-intensive industries and provide local income and employment. Such co-benefits should be included in any cost-benefit analysis. Regardless of renewable energy’s contribution to reducing climate change, the world is already committed to global warming and associated climate changes. Desert/remote Australia will thus inevitably get warmer, with implications for health, energy demand and other issues, and may be subject to increased extremes such as flooding, longer dry spells, more severe storms and coastal inundation. In addition, the prospect of world demand for oil from conventional sources exceeding supply will likely lead to oil shortages, higher oil prices, and additional incentives to provide alternative energy supplies. The region is heavily reliant on diesel generators and fossil fuel-powered motor vehicles and airplanes for transport for within-region mobility, the importation of goods, the tourism industry and emergency medical services. Without adaptation, climate change and peak oil will make living in desert/remote Australia less attractive, resulting in increased difficulty of attracting and retaining skilled workers, which would constrain development. This paper focuses on the climate and energy-related impacts and potential responses. These are both a challenge and an opportunity. They could provide additional employment and income, thus helping remote communities to participate in the clean energy economy of the future and thus overcome some serious social problems. The paper attempts to review current knowledge and provoke debate on relevant investment strategies, and it teases out the questions in need of further research.


2020 ◽  
Vol 12 (13) ◽  
pp. 2131
Author(s):  
Shuang Li ◽  
Kaihua Hou ◽  
Chengqi Cheng ◽  
Shizhong Li ◽  
Bo Chen

With the rapid development of large-scale satellite constellations and the increasing demand for rapid communication and emergency rescue using global satellite-based Internet, there have been new requirements for efficient algorithms for inter-communication between satellites. As the constellations of low-orbit satellites become larger, the complexities of real-time inter-satellite calculation and path planning are becoming more complicated and are increasing geometrically. To address the bottlenecks in large-scale node space computing, we introduced a global space grid. Based on this grid, an efficient calculation method of spatial inter-connection between satellite constellations is proposed, according to the concept of “storage for computing” and the high computational efficiency of the spatial grid model. This strategy includes the following parts: (1) the introduction of the GeoSOT-3D global grid model into aerospace and the construction of the aerospace grid indexing BigTable; (2) a set of algorithms for satellite visibility analysis according to the visible grid look-up table and the secondary grid index; and (3) planning inter-satellite routing by querying the grid’s inherent visibility. The idea at the basis of this method is to employ the “space for time” concept to convert the high-dimensional floating operations into one-dimensional matching operations by querying the inherent “visible” attribute of the grid. In our study, we simulated thousands of satellites, discretized their trajectories into grids, and pre-calculated the visibility between grid cells to plan the routing path for the ground data transmission. The theoretical analysis and experimental verification show that the algorithm is feasible and efficient, and it can significantly improve the computational efficiency of inter-satellite connection. We hope that the method can be used in emergency communications, disaster warning, and maritime rescue, and can contribute to the next generation of satellite internet and “satellite-ground” integrated networks.


Mathematics ◽  
2021 ◽  
Vol 9 (16) ◽  
pp. 1994
Author(s):  
Pamela Hermosilla ◽  
Claudio Quiroz ◽  
Francisco Cabrejos ◽  
Felipe Muñoz-La Rivera

In response to increased energy consumption and CO2 emissions, various energy efficiency policies, standards and housing certifications have emerged around the world. These aim to measure and quantify energy efficiency and endorse homes for meeting certain standards according to consistent categories that vary by continent or country. These energy rating systems correspond to a series of criteria and formulations that, through the calculation and combination of multiple variables, establish the classification values. In Chile, there is the Energy Rating System for Housing (CEV), which performs energy efficiency calculations using dynamic heat balance spreadsheets in Microsoft® Excel. When applied for everyday use and at a large scale, this system has the disadvantage of requiring a great deal of processing time for each simulation. This research proposes an improvement to the CEV energy demand calculation mechanism by generating a solution that takes advantage of the use of multiprocessors and implements the various algorithms in the C programming language. The results show that the CEV values obtained with the proposed calculation engine are equal to those of the current system but demonstrate a 76.5% improvement in their processing time.


2007 ◽  
Vol 362 (1487) ◽  
pp. 2061-2078 ◽  
Author(s):  
Brad A Seibel ◽  
Jeffrey C Drazen

The rates of metabolism in animals vary tremendously throughout the biosphere. The origins of this variation are a matter of active debate with some scientists highlighting the importance of anatomical or environmental constraints, while others emphasize the diversity of ecological roles that organisms play and the associated energy demands. Here, we analyse metabolic rates in diverse marine taxa, with special emphasis on patterns of metabolic rate across a depth gradient, in an effort to understand the extent and underlying causes of variation. The conclusion from this analysis is that low rates of metabolism, in the deep sea and elsewhere, do not result from resource (e.g. food or oxygen) limitation or from temperature or pressure constraint. While metabolic rates do decline strongly with depth in several important animal groups, for others metabolism in abyssal species proceeds as fast as in ecologically similar shallow-water species at equivalent temperatures. Rather, high metabolic demand follows strong selection for locomotory capacity among visual predators inhabiting well-lit oceanic waters. Relaxation of this selection where visual predation is limited provides an opportunity for reduced energy expenditure. Large-scale metabolic variation in the ocean results from interspecific differences in ecological energy demand.


2019 ◽  
Vol 9 (21) ◽  
pp. 4704 ◽  
Author(s):  
Talluri ◽  
Grasso ◽  
Chiaramonti

This work investigates minimum charging infrastructure size and cost for two typical EU urban areas and given passenger car electric vehicle (EV) fleets. Published forecasts sources were analyzed and compared with actual EU renewal fleet rate, deriving realistic EV growth figures. An analytical model, accounting for battery electric vehicle-plug-in hybrid electric vehicle (BEV-PHEV) fleets and publicly accessible and private residential charging stations (CS) were developed, with a novel data sorting method and EV fleet forecasts. Through a discrete-time Markov chain, the average daily distribution of charging events and related energy demand were estimated. The model was applied to simulated Florence and Bruxelles scenarios between 2020 and 2030, with a 1-year timestep resolution and a multiple scenario approach. EV fleet at 2030 ranged from 2.3% to 17.8% of total fleet for Florence, 4.6% to 16.5% for Bruxelles. Up to 2053 CS could be deployed in Florence and 5537 CS in Bruxelles, at estimated costs of ~8.3 and 21.4 M€ respectively. Maximum energy demand of 130 and 400 MWh was calculated for Florence and Bruxelles (10.3 MW and 31.7 MW respectively). The analysis shows some policy implications, especially as regards the distribution of fast vs. slow/medium CS, and the associated costs. The critical barrier for CS development in the two urban areas is thus likely to become the time needed to install CS in the urban context, rather than the related additional electric power and costs.


2021 ◽  
Vol 12 (1) ◽  
pp. 19
Author(s):  
Aftab Ahmed ◽  
Arshad Hussain ◽  
Shehdev Thahrani ◽  
Sultan Ahmed ◽  
Abdul Qadeer Khoso ◽  
...  

The environmental protection agency shows that the solid waste management of Karachi city lies in the underdeveloped category. Organics, paper, plastics, bread, metals, bones, textile and many other components are key in this area. The current methods for disposing of solid waste in cities, land-filling and other schemes are compared. Energy crises and solid waste at this large scale has forced cities to the edges of collapsing. Still, it is feasible to convert this huge problem into a profitable business. With the exception of dumping or burning, waste can be used to produce energy. Through bio-chemical and thermo-chemical processes, almost 0.01% of the total energy demand can be reproduced from the waste mentioned above. There is a need to promote the production of energy from solid waste and the utilization of different wastes in a useful manner. Instead of using ineffective waste management schemes, proper waste management schemes can solve both problems at the same time. A huge amount of revenue can be generated from Karachi solid waste, but all this depends upon awareness and suitable technology. The focus of this paper is to emphasize the importance of recycling and energy. The choice of proper methods for treatment, fermentation, anaerobic digestion and the reasons for properly operating all solid waste management bodies are discussed in detail in this study. The Decision support System tool and its importance is also discussed in terms of the field of solid waste choice makers.


2019 ◽  
Vol 116 ◽  
pp. 00040
Author(s):  
Ewelina Krawczak

Although the total energy production from fossil fuels in Poland has been decreasing for the past few years, still at least 80% of the total energy consumption derives from coal. To reduce this high consumption rate alternative energy sources should be developed. One of the most promising is photovoltaics. This paper presents modeling studies of large scale PV power plant design to fulfil the electricity needs of a small community located in Poland. Based on the energy demand prognosis and monthly solar radiation data PV power plant capacity and a number of modules were computed. The distance between rows of the modules was also determined to avoid the shadowing effect. System configuration and energy production simulations were carried out using DDS-Cad software. Results of energy calculations were compared with the yearly energy needs of the studied community. Reduction of greenhouse gases emission was estimated. Modeling results show that proposed 3.1 MWp photovoltaic plant can produce enough energy to fulfil the yearly energy demand of the households in the studied area. Moreover, significant reduction of CO2 emission and other gaseous pollutants were observed.


2020 ◽  
Vol 46 (3) ◽  
pp. 299-303
Author(s):  
Kulkarni Milind B. ◽  
P.M. Ghanegaonkar

Disposal of floral waste into water or landfill because of religious beliefs causes water and soil pollution. The purpose of present experimental work is to find an energy proficient solution for the disposal of floral waste. The method used in the present work includes anaerobic digestion of floral waste for biogas generation. The proposed method aims to follow waste-to-energy approach, for meeting the local energy demands. The techniques for getting enhanced biogas production from floral waste include novel alkaline chemical pretreatment of floral waste, and co-digestion of floral waste along with food waste. Alkaline chemical pretreatment of floral waste using sodium carbonate showed improved biogas production up to 106%, as compared to the traditional sodium hydroxide chemical pretreatment. Also, a reduction in the cost of chemical pretreatment up to 90% was possible. Co-digestion of floral waste along with food waste was also found effective for getting enhanced biogas output. A feedstock mixture of 70% of floral waste and 30% food waste could produce 32.6% more biogas than the singular feedstock in the form of floral waste. Alkaline pretreatment of floral waste using sodium carbonate and co-digestion with food waste seem to be the novelty of the work. Application of chemical absorption technique for biogas quality improvement could enrich the methane content of biogas up to 96%. Large-scale application of the proposed techniques of solid waste management can meet the energy demands at potential locations. The biogas with enriched methane content can suitable for widespread applications, such as vehicular applications and electricity generation for the benefit of the end users.


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