Energy use efficiency in greenhouse tomato production in Iran

Efficient use of energy in agriculture is one of the conditions for sustainable production. In the present study energy use pattern for tomato production in Iran was investigated and a non-parametric data envelopment analysis (DEA) technique was applied to analyze the technical and scale efficiencies of farmers with respect to energy use for crop production. The energy use pattern indicated that diesel, electricity and chemical fertilizers are the major energy consuming inputs for tomato production in the region. Moreover, the results of DEA application revealed that of the average pure technical, technical and scale efficiencies of farmers were 0.94, 0.82 and 0.86, respectively. Also the results revealed that by adopting the recommendations based on the present study, on an average, about 25.15% of the total input energy could be saved without reducing the tomato yield.     

Improving energy use efficiency of canola production using data envelopment analysis (DEA) approach

In this study energy use pattern for canola production in Golestan province of Iran was studied and the degrees of technical and scale efficiency of producers were analyzed using a non-parametric data envelopment analysis technique. The study also helped to identify the wasteful uses of energy by inefficient farmers and to suggest reasonable savings in energy uses from different inputs. Further, the effect of optimization of energy on energy ratio and energy productivity was investigated. Data used in this study were obtained from 130 randomly selected canola farms from Golestan, the most important center of canola production in Iran. The inputs were human labor, diesel, machinery, fertilizers, chemicals, water for irrigation, seeds and electrical energies; while the yield value of canola was considered as output. The results revealed that, the total energy of 17,786 MJ ha⁻¹ was consumed for canola production; about 15% of farmers were found to be technically efficient and the mean efficiency of farmers was found to be 0.74 and 0.88 under constant and variable returns to scale assumptions, respectively. The results also suggested that, on average, a potential 9.5% (1696 MJ ha⁻¹) reduction in total energy input could be achieved provided that all farmers operated efficiently.     

Linear programming models for measuring economy-wide energy efficiency performance

Data envelopment analysis (DEA) has recently gained popularity in energy efficiency analysis. A common feature of the previously proposed DEA models for measuring energy efficiency performance is that they treat energy consumption as an input within a production framework without considering undesirable outputs. However, energy use results in the generation of undesirable outputs as by-products of producing desirable outputs. Within a joint production framework of both desirable and undesirable outputs, this paper presents several DEA-type linear programming models for measuring economy-wide energy efficiency performance. In addition to considering undesirable outputs, our models treat different energy sources as different inputs so that changes in energy mix could be accounted for in evaluating energy efficiency. The proposed models are applied to measure the energy efficiency performances of 21 OECD countries and the results obtained are presented.     

Study on energy efficiency in corn production of Iran

The aims of this study are determining the energy use, qualitative analyzing of energy flow and also investigating energy efficiency by Data Envelopment Analysis (DEA) in corn production of Iran during a seven years period. Results indicated that the average of total energy input increased from 40.98 GJ ha⁻¹ in 2001 to 63.64 GJ ha⁻¹ in the year of 2007. Similarly, the average of total output energy rose from 89.03 to 107.54 GJ ha⁻¹ in the same years, respectively. Also the results showed that average energy use efficiency, energy productivity, specific energy and net energy gain in the studied period was 2.59, 0.17 kg MJ⁻¹, 7.24 MJ kg⁻¹ and 51.34 GJ ha⁻¹, respectively. DEA considered the yield (kg ha⁻¹) as output and three major energy inputs; fertilizers, diesel fuel and machinery as input of 10 provinces in each year. Findings revealed that average energy efficiency score was 90.26%. There is impermanent trend in growth of energy efficiency in corn production of Iran, which needed to further analysis in future studies to realize relevant fluctuations in corn farming.     

An analysis of energy use efficiency of canola production in Turkey

In this study, a survey and economic analysis regarding the use of input have been performed with canola farmers in the Trakya region of Turkey; survey data were obtained from 100 farmers, face-to-face. The average energy use efficiency is 4.68 and this value increases as farm size increases; according to the results of this study, energy is used more efficiently in large farms. The difference between average input and output energy is 67259.36 (MJ ha⁻¹). The specific energies of small, medium, and large farms are 62584.37, 69836.21, and 74405.43 respectively. The ratio of direct and indirect energy sources are 24.69%, and 75.31% respectively, and the benefit–cost ratio of canola production is 2.09.     

Dynamic planning,conversion, and management strategy of different renewable energy sources: A Sustainable Solution for Severe Energy Crises in Emerging Economies

Green hydrogen energy is a natural substitute for fuel-based energy and it increases a country's long-term energy safety. Pakistan has been a victim of a severe energy crisis for the past few decades. In this context, this research addresses green hydrogen generation and renewable energy supply (i.e., wind, solar, biomass, public waste, geothermal and small hydropower) as an alternate energy source in Pakistan. The assessment is carried out through a two-step framework (i.e., Fuzzy-AHP and non-parametric DEA). Results show that Pakistan has abundant renewable power capacity from wind, which the light-duty transport in the country can opt. Almost 4.89 billion gallons of fuel are consumed annually in Sindh, whereas Punjab uses up around 6.92 billion gallons of fuel annually, which need to be substituted with 1.63 billion kg and 2.31 billion kg of wind-produced hydrogen, respectively. It has been discovered that solar and wind energy attain the same criterion of weights (i.e., 0.070) in-line with the commercial potential criterion. Besides, wind-generated power is ideal for green hydrogen generation in Pakistan, and the subsequent choice for green hydrogen energy is small hydropower and solar, which are also good for green hydrogen generation in the country. Hence, this research offers a solid recommendation for the use of wind energy, which is ideal for the production of Green Hydrogen energy in the country.     

Energy use and economical analysis of sugar beet production in Tokat province of Turkey

The purposes of this study were to determine energy consumption of input and output used in sugar beet production, and to make a cost analysis in Tokat, Turkey. Data were collected from 146 sugar beet farms in Tokat, Turkey by using a face-to-face questionnaire performed in January and February 2005. Farms were selected based on random sampling method. The results revealed that total energy consumption in sugar beet production was 39 685.51 MJ ha⁻¹, and accounted for 49.33% of fertilizer energy, and 24.16% of diesel energy. The output/input energy ratio was 25.75 and energy productivity was 1.53 kg MJ ha⁻¹. Results further indicated that 82.43% of total energy input was in non-renewable energy form, and only 12.82% was in renewable form. Economic analyses showed that profit–cost ratio of farms was 1.17. The highest energy cost items were labor, land renting, depreciation and fertilizers. Although intensive energy consumption in sugar beet production increased the yield, it also resulted in problems such as global warming, land degradation, nutrient loading and pesticide pollution. Therefore, there is a need to pursue a new policy to force producers to undertake energy-efficient practices to establish sustainable production systems without disrupting the natural resources. In addition, extension activities are needed to improve the efficiency of energy consumption and to sustain the natural resources.     

Energy efficiency measurement in agriculture with imprecise energy content information

Measuring energy efficiency is crucial when planning energy reduction policies. However, decision makers are understandably reluctant to act in the absence of solid data and results supporting a policy position. This paper proposes a methodology to measure the energy efficiency of farms based on the Data Envelopment Analysis (DEA) approach. In a manner similar to the cost framework, we decompose energy efficiency measurements into technical and allocative efficiencies in energy contents of inputs. In this study, we replace input prices used in traditional economic efficiency measurements by their energy content. We use the energy efficiency model to explore the optimal input-mix that produces the current outputs at minimum energy-consumption. We demonstrate that this decomposition can help policy makers design accurate energy policies. However, the uncertainty of the data and, more particularly, the energy content of the inputs leads us to recommend using the methodologies to calculate the bounds of efficiency to obtain more plausible and robust results. Based on our analysis, energy efficiency is not a fixed value, and policy-makers should consider it with caution. We use a 2007 database of French farms specialised in field crops for empirical illustration.     

Effective use of hydrogen sulfide and natural gas resources available in the Black Sea for hydrogen economy

In this article, we propose a novel system to effectively deploy an integrated fuel processing system for hydrogen sulfide and natural gas resources available in the Black Sea to be used for a quick transition to the hydrogen economy. In this regard, the proposed system utilizes offshore wind and offshore photovoltaic power plants to meet the electricity demand of the electrolyzer. A PEM electrolyzer unit generates hydrogen from hydrogen sulfide that is available in the Black Sea deep water. The generated hydrogen and sulfur gas from hydrogen sulfide are stored in high-pressure tanks for later use. Hydrogen is blended with natural gas, and the blend is utilized for industrial and residential applications. The investigated system is modeled with the Aspen Plus software, and hydrogen production, blending, and combustion processes are analyzed accordingly. With the hydrogen addition up to 20% in the blend, the carbon dioxide emissions of combustion decrease from 14.7 kmol/h to 11.7 kmol/h, when the annual cost of natural gas is reduced from 9 billion $ to 8.3 billion $. The energy and exergy efficiencies for the combustion process are increased from 84% to 97% and from 62% to 72%, respectively by a 20% by volume hydrogen addition into natural gas.     

Renewable energy and macroeconomic efficiency of OECD and non-OECD economies

This article analyzes the effects of renewable energy on the technical efficiency of 45 economies during the 2001–2002 period through data envelopment analysis (DEA). In our DEA model, labor, capital stock, and energy consumption are the three inputs and real GDP is the single output. Increasing the use of renewable energy improves an economy's technical efficiency. Conversely, increasing the input of traditional energy decreases technical efficiency. Compared to non-OECD economies, OECD economies have higher technical efficiency and a higher share of geothermal, solar, tide, and wind fuels in renewable energy. However, non-OECD economies have a higher share of renewable energy in their total energy supply than OECD economies.     

Environment-adjusted regional energy efficiency in Taiwan

This study applies the four-stage DEA procedure to calculate the energy efficiency of 23 regions in Taiwan from 1998 to 2007. After controlling for the effects of external environments, only Taipei City, Chiayi City, and Kaohsiung City are energy efficient. Note that Kaohsiung City reaches the efficiency frontier due to the adjustment via partial environmental factors such as higher education attainment and transport vehicles. We also find a worsening trend for Taiwan’s energy efficiency. Not only is there a gap of energy efficiency between Taiwan’s metropolitan areas and the other regions, but the gap has also widened in recent years. Those inefficient counties should be given priority and the savings potential. Except for road density, the evidence indicates that each environmental factor has partial incremental effects on input slacks. As more cars and motorcycles are unfavorable externalities affecting partial energy efficiency, the central government should help local governments retire inefficient old motor vehicles, encourage energy-saving vehicle models, and provide convenient mass transportation systems. Besides, people with higher education cause industrial energy inefficient in Taiwan. The conscious of effective energy saving is necessary to schools, communities, and employee accordingly.     

An assessment of electrolytic hydrogen production from H2S in Black Sea waters

In the deeper parts of the Black Sea basin, water is anoxic. Hydrogen sulfide (H₂S) occurs naturally, and its concentration is nearly constant, around 9.5 mg/L at 1500 m depth. Its high solubility, and the existing chemical environment facilitate its accumulation and containment in the seawater, and its extraction poses a challenge.Possibility of hydrogen and sulfur production from H₂S contained in the waters of Black Sea is investigated conceptually. A multistage process is considered which involves extraction of seawater, adsorption of H₂S, electrochemical production of hydrogen and polysulfides; fresh water production by desalination of seawater and further hydrogen production from the resulting salty solution through chlorine-alkaline electrolysis. Some consideration is included regarding the economic and environmental aspects of the process.     

Energy efficiency trends and policy in Slovenia

The energy dependency of Slovenia is high (52.1%), but it is a little lower than the average energy dependency in the EU 27 (53.8%). Slovenia imports all its petroleum products and natural gas and partly coal and electricity. The energy intensity of Slovenia is higher by about 50% than the average in the EU 27. The target of the EU Directive on energy end-use efficiency and energy services adopted in 2006 is to achieve a 9% improvement of EE (energy efficiency) within the period 2008-2016. The new target of the EU climate and energy package “20-20-20 plan” is a 20% increase in EE by 2020. Since 1991 the Slovenian government has been supporting energy efficiency activities. The improvement of EE was one of the targets of strategic energy documents ReSROE (Resolution on the Strategy of Use and Supply of Energy in Slovenia from 1996 and ReNEP (Resolution on the National Energy Programme) from 2004 adopted by the Slovenian National Assembly (Parliament) in previous years. The Energy Act adopted in 1999 defines the objective of energy policy as giving priority to EE and utilization of renewable energy sources. The goals of the “National Energy Action Plan 2008-2016 (NEEAP)” adopted by the Slovenian government in 2008 include a set of energy efficiency improvement instruments in the residential, industrial, transport and tertiary sectors. The target of the NEEAP is to save final energy in the 2008-2016 period, amounting to at least 4261 GWh or 9% of baseline consumption. The indicators of energy efficiency trends show considerable improvement in the period from 1998 to 2007. The improvement of EE was reached in all sectors: manufacturing, transport and households. The paper analyses the structure, trends of energy consumption and energy efficiency indicators by sectors of economic activity. A review of energy efficiency policy and measures is described in the paper.     

Optimization of energy consumption for soybean production using Data Envelopment Analysis (DEA) approach

In this study a non-parametric method of Data Envelopment Analysis (DEA) is used to estimate the energy efficiencies of soybean producers based on eight energy inputs including human labor, diesel fuel, machinery, fertilizers, chemicals, water for irrigation, electricity and seed energy and single output of grain yield. The study also helps to rank efficient and inefficient farmers and to identify optimal energy requirement and wasteful uses of energy. Data were collected using face-to-face surveys from 94 farms in Golestan province which is the most important center of soybean production in Iran. Based on the results, average yield and energy consumption for soybean production were 3233.15 kg ha⁻¹ and 35372.23 MJ ha⁻¹, respectively. Also, the results of DEA application showed that, the technical, pure technical and scale efficiencies of farmers were 0.853, 0.919 and 0.926, respectively. Moreover, energy saving target ratio for soybean production was calculated as 20.12%, indicating that by following the recommendations resulted from this study, about 7116.84 MJ ha⁻¹ of total input energy could be saved while holding the constant level of soybean yield. Also, electrical energy had the highest share (78.08%) from total saving energy, followed by fertilizers (10.46%) and diesel fuel (6.18%) energy inputs.     

Energy use efficiency in the Indian manufacturing sector: An interstate analysis

This paper approaches the measurement of energy efficiency from a production theoretic framework and uses Data Envelopment Analysis to measure energy efficiency in the Indian manufacturing sector. Using data from the Annual Survey of Industries for the years 1998–99 through 2003–04, the study compares the energy efficiency in manufacturing across states, based on several models. The results show considerable variation in energy efficiency across states. Comparing the results across our models, we find that the relative pricing of energy does not provide the appropriate incentives for energy conservation. A second-stage regression analysis reveals that states with a larger share of manufacturing output in energy-intensive industries have lower energy efficiency. Also, higher quality labor force associates with higher energy efficiency. Finally, the power sector reforms have not yet had any significant impact on achieving energy efficiency.     

Energy efficiency in the transport sector

The distribution of energy use in the transport sector in the United States of America is presented and analysed in terms of the efficient use of energy in various applications. Comparisons are drawn with other modelling efforts.     

Total-factor energy efficiency of regions in Japan

This study computes the regional total-factor energy efficiency (TFEE) in Japan by employing the data envelopment analysis (DEA). A dataset of 47 prefectures in Japan for the period 1993–2003 is constructed. There are 14 inputs, including three production factors (labor employment, private, and public capital stocks) and 11 energy sources (electric power for commercial and industrial use, electric power for residential use, gasoline, kerosene, heavy oil, light oil, city gas, butane gas, propane gas, coal, and coke). GDP is the sole output. Following Fukao and Yue [2000. Regional factor inputs and convergence in Japan—how much can we apply closed economy neoclassical growth models? Economic Review 51, 136–151 (in Japanese)], data on private and public capital stocks are extended. All the nominal variables are transformed into real variables, taking into consideration the 1995 price level. For kerosene, gas oil, heavy oil, butane gas, coal, and coke, there are a few prefectures with TFEEs less than 0.7. The five most inefficient prefectures are Niigata, Wakayama, Hyogo, Chiba, and Yamaguchi. Inland regions and most regions along the Sea of Japan are efficient in energy use. Most of the inefficient prefectures that are developing mainly upon energy-intensive industries are located along the Pacific Belt Zone. A U-shaped relation similar to the environmental Kuznets curve (EKC) is discovered between energy efficiency and per capita income for the regions in Japan.     

Energy security,efficiency and carbon emission of Chinese industry

For the Chinese industry as the mainstay of the national economy and dominant energy user and carbon emitter, an integrative assessment is performed from major energy policy perspectives of energy security, energy efficiency and carbon emission. Extensive systems indicators, including oil dependence ratio, average oil growth rate; indices of energy diversity, of carbonization and of oil growth risk; ratios of energy use to output, to value added and to compensation for laborers; ratios of carbon emission to output, to value added and to compensation for laborers, are devised to assess the Chinese industry 2002–2007 with most recent statistics availability. Combined indicators are identified by sparse principle component analysis to characterize sector performances. The industrial sectors are classified into five clusters and the main features of each cluster are pinpointed using fuzzy clustering algorithm. Concrete results facilitate comparisons of sectors to enable more accurate policy recommendations.