Assessment of the Turkish utility sector through energy and exergy analyses

The present study deals with evaluating the utility sector in terms of energetic and exergetic aspects. In this regard, energy and exergy utilization efficiencies in the Turkish utility sector over a wide range of period from 1990 to 2004 are assessed in this study. Energy and exergy analyses are performed for eight power plant modes, while they are based on the actual data over the period studied. Sectoral energy and exergy analyses are conducted to study the variations of energy and exergy efficiencies for each power plants throughout the years, and overall energy and exergy efficiencies are compared for these power plants. The energy utilization efficiencies for the overall Turkish utility sector range from 32.64% to 45.69%, while the exergy utilization efficiencies vary from 32.20% to 46.81% in the analyzed years. Exergetic improvement potential for this sector are also determined to be 332 PJ in 2004. It may be concluded that the methodology used in this study is practical and useful for analyzing sectoral and subsectoral energy and exergy utilization to determine how efficient energy and exergy are used in the sector studied. It is also expected that the results of this study will be helpful in developing highly applicable and productive planning for energy policies.     

Assessment of the energy utilization efficiency in the Turkish transportation sector between 2000 and 2020 using energy and exergy analysis method

Energy and exergy utilization efficiencies in the Turkish transportation sector over the period from 2000 to 2020 are evaluated in this study. A comparison of the overall energy and exergy efficiencies of the Turkish transportation sector with the other countries is also presented. Energy and exergy analyses are performed for four transport modes, namely roadway, railway, airway and seaway, while they are based on the actual data for 2000 and projected data for 2020. Roadway appears to be the most efficient mode when compared with railway, air and seaway. It is projected that about 15% of total energy resources will be used in this sector during 2020. The energy utilization efficiencies for the Turkish transportation sector range from 23.71% in 2000 to 28.75% in 2020, while the exergy utilization efficiencies vary from 23.65% to 28.85% in the same years, respectively. Exergetic improvement potential for this sector is estimated to be 700 PJ in 2020, with an average increase rate of 4.5% annually between 2000 and 2020. Road transport and oil-fuelled combustion engines offer the principal scope for exergetic improvement in the coming decades. It may be concluded that the methodology used in this study is practical and useful for analyzing sectoral energy and exergy utilization to determine how efficiently energy and exergy are used in the sector studied. It is also expected that this study will be helpful in developing highly applicable and productive planning for energy policies.     

Energy and exergy analyses of energy consumptions in the industrial sector in South Africa

The energy-utilization over a 10-year period (1994–2003) has been analysed for the South African industrial sector, which consumes more primary energy than any other sector of the economy. Four principal sub-sectors, namely iron and steel, chemical and petrochemical, mining and quarrying, and non-ferrous metals/non-metallic minerals were considered in this study. Primary-energy utilization data were used to calculate the weighted mean energy and exergy efficiencies for the sub-sectors and then overall values for the industrial sector were obtained. The results indicate that exergy efficiency is considerably lower than energy efficiency in all the sub-sectors, particularly in mining and quarrying processes, for which the values were approximately 83% and 16%, respectively. The performance of exergy utilization in the industrial sector can be improved by introducing various conservation strategies. Results from this study were compared with those for other countries.     

Analysis of sectoral energy and exergy use of Saudi Arabia

This paper presents the analysis of sectoral energy and exergy utilization of Saudi Arabia by considering the energy and exergy flows for the 12 years between 1990 and 2001. Sectoral energy and exergy efficiencies are obtained for the subsectors and the devices used in each sector. Energy and exergy flow diagrams for Saudi Arabia are also presented, respectively, to illustrate the situation on how energy and exergy efficiencies vary in each sector. The residential sector appears to be the most energy efficient sector, and the industrial sector to be the most exergy efficient. It is believed that the current methodology is useful for analyzing sectoral energy and exergy utilization, which will help Saudi Arabia with energy savings through energy efficiency and/or energy conservation measures. It is also be helpful to establish standards to facilitate application in various sectors and processes for a sustainable energy planning. Copyright © 2004 John Wiley & Sons, Ltd.     

Exergoeconomic aspects of sectoral energy utilization for Turkish industrial sector and their impact on energy policies

This study deals with this thermo-economic analysis of energy utilization in the industrial sector (IS) towards establishing energy policies. The relations between capital costs and thermodynamic losses for subsectors in the IS are investigated. In the analysis, Turkey is taken as an application country based on its actual data over the period from 1990 to 2003. Energy and exergy analyses are performed for eight industrial modes, namely iron–steel, chemical–petrochemical, petrochemical–feedstock, cement, fertilizer, sugar, non-metal industry, other industry. The energy and exergy utilization efficiency values for the entire Turkish IS are obtained to range from 63.45% to 70.11%, and from 29.72% to 33.23%, respectively. The ratio of thermodynamic loss rate-to-capital cost values is also calculated to vary from 0.76 to 1.01.     

Assessment of the energy and exergy utilization efficiencies in the Turkish agricultural sector

This study deals with evaluating the energy and exergy utilization efficiencies in the Turkish agricultural sector over a 12‐year period from 1990 to 2001. In the energy and exergy analyses, two main energy sources, namely fuels and electricity, are taken into consideration, while the sectoral energy and exergy efficiencies are compared for this period. These main energy sources include diesel for tractors and other vehicles, and electricity for pumps. Overall energy utilization efficiencies are obtained to vary between 29.1 and 41.1%, while overall exergy utilization efficiencies are found to range from 27.9 to 37.4% in the analysed years, respectively. It may be concluded that the present technique proposed here may be used as a useful tool in analysing and evaluating the energy and exergy utilization efficiencies, identifying energy efficiency and/or energy conservation opportunities and dictating the energy strategies of countries. Copyright © 2005 John Wiley & Sons, Ltd.     

Estimating the energy and exergy utilization efficiencies for the residential–commercial sector: an application

The main objectives in carrying out the present study are twofold, namely to estimate the energy and exergy utilization efficiencies for the residential–commercial sector and to compare those of various countries with each other. In this regard, Turkey is given as an illustrative example with its latest figures in 2002 since the data related to the following years are still being processed. Total energy and exergy inputs in this year are calculated to be 3257.20 and 3212.42 PJ, respectively. Annual fuel consumptions in space heating, water heating and cooking activities as well as electrical energy uses by appliances are also determined. The energy and exergy utilization efficiency values for the Turkish residential–commercial sector are obtained to be 55.58% and 9.33%, respectively. Besides this, Turkey's overall energy and exergy utilization efficiencies are found to be 46.02% and 24.99%, respectively. The present study clearly indicates the necessity of the planned studies toward increasing exergy utilization efficiencies in the sector studied.     

Energy and exergy efficiencies in Turkish transportation sector, 1988–2004

This study aims at examining energy and exergy efficiencies in Turkish transportation sector. Unlike the previous studies, historical data is used to investigate the development of efficiencies of 17 years period from 1988 to 2004. The energy consumption values in tons-of-oil equivalent for eight transport modes of four transportation subsectors of the Turkish transportation sector, including hard coal, lignite, oil, and electricity for railways, oil for seaways and airways, and oil and natural gas for highways, are used. The weighted mean energy and exergy efficiencies are calculated for each mode of transport by multiplying weighting factors with efficiency values of that mode. They are then summed up to calculate the weighted mean overall efficiencies for a particular year. Although the energy and exergy efficiencies in Turkish transport sector are slightly improved from 1988 to 2004, the historical pattern is cyclic. The energy efficieny is found to range from 22.16% (2002) to 22.62% (1998 and 2004) with a mean of 22.42±0.14% and exergy efficiency to range from 22.39% (2002) to 22.85% (1998 and 2004) with a mean of 22.65±0.15%. Overall energy and exergy efficiencies of the transport sector consist mostly of energy and exergy efficiencies of the highways subsector in percentages varying from 81.5% in 2004 to 91.7% in 2002. The rest of them are consisted of other subsectors such as railways, seaways, and airways. The overall efficiency patterns are basically controlled by the fuel consumption in airways in spite of this subsector's consisting only a small fraction of total. The major reasons for this are that airways efficiencies and the rate of change in fuel consumption in airways are greater than those of the others. This study shows that airway transportation should be increased to improve the energy and exergy efficiencies of the Turkish transport sectors. However, it should also be noted that no innovations and other advances in transport technologies are included in the calculations. The future studies including such details will certainly help energy analysts and policy makers more than our study.     

Energy and exergy utilization in agricultural sector of Saudi Arabia

This paper presents an analysis of energy and exergy utilization in the agricultural sector of Saudi Arabia by considering the sectoral energy and exergy flows for a period of 12 years between 1990 and 2001. Energy and exergy analyses are conducted for its two essential devices, namely tractors and pumps, and hence the sectoral energy and exergy efficiencies are obtained for comparison for a period of 12 years. Two main energy sources are diesel for tractors and electricity for pumps in the sector. It is found that the overall exergy efficiencies in this sector are slightly less than the corresponding energy efficiencies, e.g. 74.19–69.20% for exergy efficiency and 74.94–74.60% for energy efficiency from 1990 to 2001. The present technique is proposed as a useful tool in sectoral analysis of energy and exergy utilization, developing energy policies and providing energy conservation measures.     

An application of energy and exergy analysis in residential sector of Malaysia

In this paper, the useful concept of energy and exergy utilization is defined, analyzed and applied to the residential sector of Malaysia by taking into account the energy and exergy flows for a period of 8 years from the year 1997 to 2004. The energy and exergy efficiencies are determined for the devices used in this sector and found to be 70% and 28%, respectively. Energy and exergy flow diagrams for the overall efficiencies of Malaysian residential sector are also illustrated in this paper. It is found that the current methodology applied in Saudi Arabia is suitable to analyze energy and exergy use in Malaysian residential sector. It has been found that the exergy efficiency of the Malaysian residential sector appears to be much lower than its corresponding energy efficiency. It has been observed that about 21% of total exergy losses are caused by refrigerator-freezer and 12% of total loss is caused by air conditioner. Washing machine, fan and rice cooker contribute about 11%, 10% and 8% of total exergy losses, respectively.     

Exergy analysis of the energy use in Greece

In this work, an analysis is being done on the concept of energy and exergy utilization and an application to the residential and industrial sector of Greece. The energy and exergy flows over the period from 1990 to 2004 were taken into consideration. This period was chosen based on the data reliability. The energy and exergy efficiencies are calculated for the residential and industrial sectors and compared to the findings of a previous study concerning the exergy efficiency of the Greek transport sector. The residential energy and exergy efficiencies for the year 2003 were 22.36% and 20.92%, respectively, whereas the industrial energy and exergy efficiencies for the same year were 53.72% and 51.34%, respectively. The analysis of energy and exergy utilization determines the efficiency of the economy as a whole. The results can play an important role in the establishment of efficiency standards of the energy use in various economy sectors. These standards could be utilized by energy policy makers.     

Energy and exergy utilization in Turkey during 1995

Energy and exergy utilization in Turkey have been analysed. We have evaluated the conversion sector and end uses for transportation, industrial, residential and commercial applications. Energy efficiencies are about 15% for transportation, 45% for thermal and hydropower plants, 55% for residential and commercial uses and 58% for industrial applications. The exergy efficiencies are about 6% for residential and commercial uses, 15% for transportation, 33% for industrial applications and 45% for the utility sector. Overall averages are 35% for energy and 13% for exergy utilization.     

Energy and exergy utilizations of the U.S. manufacturing sector

The energy and exergy utilizations in the U.S. manufacturing sector are analyzed by considering the energy and exergy flows for the year 2002. Detailed end-use models for fourteen intensive industries are established using scattered data from the Manufacturing Energy Consumption Survey (MECS). Since the MECS data exhibit many gaps, data from other sources are used, as well as a number of assumptions are made to complete the models. The methodology applied and the assumptions made are clearly described so that the methods can be readily modified to fit different needs. The end-use models provide a starting point to estimate the site and embodied energy and exergy efficiencies. The average site energy and exergy efficiencies of the manufacturing sector are estimated as 63.5% and 38.8% respectively, while the embodied energy and exergy efficiencies are estimated as 52.7% and 32.1% respectively. The low efficiency values suggest that many opportunities for better industrial energy utilization still exist.     

An application of energy and exergy analysis in agricultural sector of Malaysia

Thermodynamic losses usually take place in machineries used for agricultural activities. Therefore, it is important to identify and quantify the losses in order to devise strategies or policies to reduce them. An exergy analysis is a tool that can identify the losses occurred in any sector. In this study, an analysis has been carried out to estimate energy and exergy consumption of the agricultural sector in Malaysia. Energy and exergy efficiencies have been determined for the devices used in the agricultural sector of Malaysia, where petrol, diesel and fuel oil are used to run the machineries. Energy and exergy flow diagrams for the overall efficiencies of Malaysian agricultural sector are presented as well. The average overall energy and exergy efficiencies of this sector were found to be 22% and 20.728%, respectively, within the period from 1991 to 2009. These figures were found to be lower than those of Norway but higher than Turkey.     

Energetic and exergetic aspects of cotton stalk production in establishing energy policies

Exergy analysis is important for energy resource utilization, because exergy, which is a way to a sustainable future, is a part of the energy analysis. Exergy analysis starts to play a role in several countries in developing energy policy. This paper deals with the exergetic assessment of the cotton stalk (CS) production. In this regard, Turkey, which is one of the eight countries producing 85% of the world's cotton, is given as an application country first. Energy and exergy relations used in the analysis are then presented. Finally, the Turkish CS production in 2003 is evaluated using energy and exergy analyses method, while the results obtained are discussed. The values for the net energy and exergy gained are obtained to be about 49,146 and 59,395 MJ/ha, respectively. Turkey's total energy and exergy are estimated to be 75.45 and 81.87 PJ. It may be concluded that this amount of energy is equal to 7.77% and 2.38% of Turkey's primary energy production and consumption in the same year, respectively. The overall mean energy and exergy efficiencies of the cotton production in the year studied are found to be 33.06% and 33.12%, respectively. It is also expected that the results of this study will be helpful in developing highly applicable and productive planning for energy policies.     

A review on analyzing and evaluating the energy utilization efficiency of countries

In recent years, there has been an increasing interest in applying energy and exergy analysis modeling techniques for energy-utilization assessments in order to attain energy saving. In this regard, various approaches have been used to perform the exergy analyses of countries. The main objective of the present study is to evaluate and analyze the energy utilization efficiencies of countries by reviewing the studies conducted on various countries or societies, to which different approaches have been applied. Thermodynamic relations used to perform energy and exergy analyses of countries are given first. The classification of studies conducted and the approaches applied are then investigated in terms of subsectors, such as utility, industrial, residential–commercial, and transportation sectors. Next, the countries considered are evaluated in terms of energy and exergy utilization efficiencies. Finally, the results obtained are discussed. It is expected that the review presented here will provide the investigators with knowledge about how much effective and efficient a country uses its natural resources. This knowledge is also needed for identifying energy efficiency and/or energy conservation opportunities as well as for dictating the energy strategies of a country or a society.     

Energy and exergy efficiencies in the Chinese transportation sector, 1980-2009

This paper aims at analyzing energy and exergy efficiencies in the Chinese transportation sector. Historical data is used to investigate the development of efficiencies from 1980 to 2009. Firstly, we calculate energy consumption values in PJ (petajoule) for nine transportation modes of five transportation sub-sectors. Then, the weighted energy and exergy efficiencies for each transportation mode, calculated by multiplying weighting factors with efficiency values of that mode, are summed up to calculate the weighted mean overall efficiencies for a particular year. We find that: (1) In 2009, the energy consumed in transportation sector was 12179.80 PJ, whereas that was 589.25 PJ in 1980. (2) Highways transport was the biggest energy consumer, which consumed 82.0% of total transport energy consumption in 2009. (3) Up to 2009, the oil consumed by transportation accounted for 75.1% of that in the whole country, which is more than the net oil import. (4) The average overall energy and exergy efficiencies are found to be 21.22% and 19.95%, respectively. (5) A comparison with other countries showed that energy and exergy efficiencies of the Chinese transportation sector are slightly lower than those of Jordan, Malaysian, Saudi Arabian and Norwegian, and higher than that incurred in Turkish.     

Turkey's sectoral energy and exergy analysis between 1999 and 2000

This study analyses sectoral energy and exergy utilization in Turkey between 1999 and 2000. Total energy and exergy utilization efficiencies are calculated to be 43.24 and 24.04% in 1999, and 44.91 and 24.78% in 2000, respectively. In order to calculate these efficiency values, Turkey is subgrouped into four main sectors, namely utility, industrial, transportation and commercial‐residential. The energy efficiency values are found to be 23.88, 30.10, 68.97 and 57.76% in 1999, and 23.71, 30.11, 68.81 and 57.05% in 2000 for transportation, utility, industrial and commercial‐residential sectors, respectively. Besides this, the exergy efficiency values are obtained to be 23.80, 30.28, 35.97 and 8.12% in 1999, and 23.65, 30.47, 35.51 and 8.02% in 2000 for the same order of sectors. The present study has clearly shown the necessity of the planned studies towards increasing exergy efficiencies in the sectors studied. Copyright © 2004 John Wiley & Sons, Ltd.     

Energy analysis and exergy utilization in the transportation sector of Jordan

The transport sector is responsible for about 37% of total final energy demand in Jordan, and thus it is considered an important driver for determining future national energy needs. This paper presents energy analysis and exergy utilization in the transportation sector of Jordan by considering the sectoral energy and exergy flows for the last two decades. The transportation sector, in Jordan, is a two-mode system, namely, road, which covers almost all domestic passenger and freight transport and airways. The latter is mainly used for international flights. The average estimated overall energy and exergy efficiencies were found as 23.2% and 22.8%, respectively. This simply indicates that there is large potential for improvement and efficiency enhancement. It is believed that the present technique is practical and useful for analyzing sectoral energy and exergy utilization to determine how efficiently energy and exergy are used in the transportation sector. It is also helpful to establish standards, based on exergy, to facilitate applications in different planning processes such as energy planning. A comparison with other countries showed that energy and exergy efficiencies of the Jordanian transport sector are slightly lower than that of Turkey, and higher than those incurred in Malaysia, Saudi Arabia and Norway. Such difference is inevitable due to dissimilar structure of the transport sector in these countries.     

An estimation of the energy and exergy efficiencies for the energy resources consumption in the transportation sector in Malaysia

The purpose of this work is to apply the useful energy and exergy analysis models for different modes of transport in Malaysia and to compare the result with a few countries. In this paper, energy and exergy efficiencies of the various sub-sectors are presented by considering the energy and exergy flows from 1995 to 2003. Respective flow diagrams to find the overall energy and exergy efficiencies of Malaysian transportation sector are also presented. The estimated overall energy efficiency ranges from 22.74% (1999) to 22.98% (1998) with a mean of 22.82±0.06%$22.82\pm 0.06\%$ and that of overall exergy efficiency ranges from 22.44% (2000) to 22.82% (1998) with a mean of 22.55±0.12%$22.55\pm 0.12\%$. The results are compared with respect to present energy and exergy efficiencies in each sub-sector. The transportation sector used about 40% of the total energy consumed in 2002. Therefore, it is important to identify the energy and exergy flows and the pertinent losses. The road sub-sector has appeared to be the most efficient one compared to the air and marine sub-sectors. Also found that the energy and exergy efficiencies of Malaysian transportation sector are lower than that of Turkey but higher than Norway.