Environmental Impacts and Sustainability
Taraneh Taheri; Mohammad Behshad Shafii; Sourena Sattari; Morteza Khalaji Assadi
Abstract
Combined Heat and Power (CHP) systems have increasingly drawn attention in recent years due to their higher efficiency and lower Greenhouse Gas (GHG) emission. Input-output matrix modeling was considered here as one of the efficient approaches for optimizing these energy networks. In this approach, power ...
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Combined Heat and Power (CHP) systems have increasingly drawn attention in recent years due to their higher efficiency and lower Greenhouse Gas (GHG) emission. Input-output matrix modeling was considered here as one of the efficient approaches for optimizing these energy networks. In this approach, power flow and energy conversion through plant components were modeled by an overall efficiency matrix including dispatch factors and plant component efficiencies. The purpose of this paper is to propose a modification of the objective function presented in some previous studies. This procedure was performed by adding the parameters of plant component lifetime and environmental costs to the objective function. Thus, the optimization problem was formulated by minimizing the total system levelized cost instead of simply hourly energy cost. The study results revealed that producing the electricity by the trigeneration system led to achieving 1256 MWh annual electricity savings that otherwise must be purchased from the grid. The results also showed a significant reduction in annual CO2 emissions (703.31 tons per year). Furthermore, if the price of purchasing CHP electricity was considered three times more than the current ones, payback times would be less than 5 years.
Environmental Impacts and Sustainability
Hasan Hekmatnia; Ahmad Fatahi Ardakani; Armin Mashayekhan; Morteza Akbari
Abstract
As a key economic element, energy plays an important role in the development of societies. Economic growth and its urgent need for energy highlight the need for optimal energy use. Wind energy is an energy source that has become an increasingly common source of electricity. In this study, socio-economic ...
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As a key economic element, energy plays an important role in the development of societies. Economic growth and its urgent need for energy highlight the need for optimal energy use. Wind energy is an energy source that has become an increasingly common source of electricity. In this study, socio-economic impacts of the cost of electricity generated by wind power plants were assessed with Iran as the focus of this study. The environmental impacts of wind energy were also considered by reviewing and analyzing research papers. Studies showed that although the use of wind energy in Iran began in Manjil in northern Iran, no significant progress has been made in this field despite all the efforts over the past years. The results indicated that the initial cost of launching wind turbines was the most important factor in the failure of this technology. The costs of purchasing turbines, construction of roads, provision of electrical infrastructure, project management, installation of turbines, insurance premiums, grid connections, and power lines were shown to affect costs of energy production. Furthermore, operation and maintenance costs, the choice of installation location, increasing production capacity, expansion of the energy market, and policies in the country can play an essential role in determining the cost of wind energy production. Given that power generation using wind turbines are economical, it is recommended that turbines be installed in suitable windy locations. In addition, considering that one of the crises facing the world and especially Iran is environmental pollution, utilizing energies such as wind energy for generating electricity is advised due to their lower pollutant emissions and lower economic and social costs.
Environmental Impacts and Sustainability
Bahram Hosseinzadeh Samani; Marziyeh Ansari Samani; Rahim Ebrahimi; Zahra Esmaeili; Ali Ansari Ardali
Abstract
Due to limited oil reserves, the rising world fuel prices and environmental problems caused by the use of fossil fuels increase the tendency to use alternative fuels such as biodiesel and bioethanol. In this study, the evaluation of energy and exergy flow from seed planting to final production of biodiesel ...
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Due to limited oil reserves, the rising world fuel prices and environmental problems caused by the use of fossil fuels increase the tendency to use alternative fuels such as biodiesel and bioethanol. In this study, the evaluation of energy and exergy flow from seed planting to final production of biodiesel from rapeseed oil was carried out. Biodiesel production from rapeseed was made in three main phases: farm, oil extraction, and industrial biodiesel production. Initially, the input and output variables for rapeseed production were collected through questionnaires from 30 rapeseed farms in Khuzestan province, Iran. Thus, the amount of energy input and output to the field for rapeseed was estimated to be 12826.98 and 22195 MJ/ha, respectively. The highest energy consumption is related to chemical fertilizers with 65 % share of other inputs. Input and output exergy rates were obtained as 3933.494 and 22603.39 MJ/ha, respectively, and the highest exergy consumption related to diesel fuel with 58 % share of other inputs. At the biodiesel production stage, the input energy and output energy were 156.95 MJ and 41.88 MJ, respectively, and the highest amount of electricity consumed was 91.02 MJ. The total amount of exergy in the production of biodiesel and the output exergy was 48.412 MJ and 64.568 MJ, respectively. In this study, the effects of alcohol-to-oil molar ratio, ultrasound power (W), catalyst concentration (w/w %), and the reaction time (min) on methyl ester yield using response surface methodology based on Box Behnken experimental design in the Design Expert software were investigated. Finally, gas emissions were studied at the planting and biodiesel production stages, and the resultsshowed that the highest greenhouse gas emissions at the planting stage were related to chemical fertilizers and alcohol production.
