Energy inputs and crop yield relationships in greenhouse winter crop tomato production

In this study, energy use patterns and the relationship between energy inputs and yield for single crop (winter) greenhouse tomato production were examined in Antalya province, one of the most important greenhouse centres in Turkey. Data were collected using face-to-face surveys from 85 farms producing winter greenhouse tomatoes. The results indicated that the bulk of energy was consumed in fertilizer (38.22%), electricity (27.09%), manure (17.33%) and diesel-oil (13.65%). Average yield and energy consumption were calculated as 57,905.1 kg/ha and 61,434.5 MJ/ha, respectively. Results also determined an output–input ratio of 0.8 and a respective energy productivity and specific energy of 1.061 MJ/t and 0.94 kg/MJ. In addition, the Cobb Douglas production function was applied to test the relationship among different forms of energy consumption. The findings suggested that single crop tomato producers must optimize their use of indirect energy resources. Single crop producers applied an excess use of chemicals, resulting in an inverse effect on yield as well as imposing risks to natural resources and human health. This research suggested an expansion in energy use training opportunities to greenhouse farmers in the region.     

Energy inputs and crop yield relationship in potato production in Hamadan province of Iran

The aim of this study was to determine energy consumption and the relationship between energy input and yield for potato production in Kaboud Rahang region of Hamadan state. The data used in this study are collected by questionnaire. The results revealed that nitrogen fertilizer (39%), diesel (21%), seed (14.9%), water (7.5%) and manure (6.4%) consumed the bulk of energy. In the surveyed farms, average yield and energy consumption were calculated as around 28613.7 kg/ha, 92296.3 MJ/ha, respectively. The results also showed that energy ratio, specific energy and energy productivity were 1.1, 3.2 MJ/kg and 0.3 kg/MJ, respectively. An econometric model was developed to estimate the impact of energy inputs on yield by using parametric methods. For this purpose, potato yield, an endogenous variable was assumed to be a function of energy inputs: fertilizer manure, chemical, machinery, human, water for irrigation, diesel and seed. The empirical results indicated that variables: fertilizer, chemical, seed and human were found statistically significant and contributed to yield. Among statistically significant exogenous variables, seed, water for irrigation, chemical, human and fertilizer were ranked in terms of elasticities.     

Economical analysis and relation between energy inputs and yield of greenhouse cucumber production in Iran

This paper studies the energy balance between the input and the output per unit area for greenhouse cucumber production. For this purpose, the data on 43 cucumber production greenhouses in the Tehran province, Iran, were collected and analyzed. The results indicated that a total energy input of 148836.76 MJ ha⁻¹ was consumed for cucumber production. Diesel fuel (with 41.94%) and chemical fertilizers (with 19.69%) were amongst the highest energy inputs for cucumber production. The energy productivity was estimated as 0.80 kg MJ⁻¹. The ratio of energy output to energy input was approximately 0.64. Results indicate 10.93% and 89.07% of total energy input was in renewable and non-renewable forms, respectively. The regression results revealed that the contribution of energy inputs on crop yield (except for fertilizers and seeds energies) was significant. The human labour energy had the highest impact (0.35) among the other inputs in greenhouse cucumber production. Econometric analysis indicated that the total cost of production for one hectare of cucumber production was around 33425.70 $. Accordingly, the benefit–cost ratio was estimated as 2.58.     

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.     

Energy demand and greenhouse gas emissions during the production of a passenger car in China

Rapidly-rising oil demand and associated greenhouse gas (GHG) emissions from road vehicles in China, passenger cars in particular, have attracted worldwide attention. As most studies to date were focused on the vehicle operation stage, the present study attempts to evaluate the energy demand and GHG emissions during the vehicle production process, which usually consists of two major stages—material production and vehicle assembly. Energy demand and GHG emissions in the material production stage are estimated using the following data: the mass of the vehicle, the distribution of material used by mass, and energy demand and GHG emissions associated with the production of each material. Energy demand in the vehicle assembly stage is estimated as a linear function of the vehicle mass, while the associated GHG emission is estimated according to the primary energy sources. It is concluded that the primary energy demand, petroleum demand and GHG emissions during the production of a medium-sized passenger car in China are 69,108 MJ, 14,545 MJ and 6575 kg carbon dioxide equivalent (CO₂-eq). Primary energy demand, petroleum demand and GHG emissions in China’s passenger car fleets in 2005 would be increased by 22%, 5% and 30%, respectively, if the vehicle production stage were included.     

Energy and cost analysis for greenhouse and open-field grape production

The objective of this study was to examine the energy use patterns and cost of production in greenhouse and open-field grape production. Data used in the study were obtained from the experiment conducted at the Akdeniz university research field. In the study, energy values were calculated by multiplying the amount of inputs and outputs by the related energy conversion factors. The results indicated that total input energy use in greenhouse and open-field production was found to be 24513.0 and 23640.9 MJ/ha, respectively. However, the output energy of greenhouse grapes (73396.0 MJ/ha) was lower than open-field grapes (120596 MJ/ha). The output–input ratio for greenhouse and open-field grape production was found to be 2.99 and 5.10, respectively. The economic analysis revealed that production costs for greenhouse grapes were higher than open-field grapes but greenhouse grapes were more profitable than open-field due to premium prices for greenhouse grapes.     

Energy conservation in the greenhouse system: A steady state analysis

We have evaluated the five typical shape of the greenhouse for energy conservation in winter months for a composite climate. An expression for the plant temperature has been used for steady state analysis. Numerical computation has been carried out for the climatic condition of Delhi, India. The evaluation of the shape of the greenhouse has been done for a given floor area. Additional energy required from other fuels to maintain the necessary temperature has also been considered. It has been observed that a standard peak uneven span is suitable for minimum use of liquefied petroleum gas for a given favourable plant temperature. Experimental validation of the thermal model has also been carried out.     

Evaluation of greenhouse residues gasification performance in hydrogen production

In this study, a modeling study was carried out to investigate the potential of hydrogen production from greenhouse tomato and pepper residues blending in different rates (0%, 25%, 50%, 75% and 100%) by air-steam gasification. The numerical model developed for the gasification system assumes that all carbon in the mixture is gasified. Air to fuel rate and steam to fuel rates are 0.05 due to high content of O₂ in biomass residues. The gasifier temperature is 877 °C (1150 K) for developed model. According to the result of this study, increasing tomato residues blending rate increases hydrogen content of syngas. It is mainly caused by the content of O₂ in tomato residues being higher than content of O₂ in pepper residues. This study shows that the O₂ content of greenhouse residues is an important factor in syngas production, especially in H₂ production.     

Energy resources' utilization in organic and conventional vineyards: Energy flow, greenhouse gas emissions and biofuel production

An energy analysis, in conventional and organic vineyards, combined with ethanol production and greenhouse gas emissions, is useful in evaluating present situation and deciding best management strategies. The objective of this study was to evaluate the differences in the energy flow between organic and conventional vineyards in three locations, to calculate CO₂, CH₄ and N₂O-emissions based on the used fossil energy and to explore if wine industry wastes can be used to extract bioethanol. The data were collected through personal interviews with farmers during 2004–2005. Eighteen farmers, who owned vineyards about 1 ha each, were randomly selected to participate in this study [(3 conventional and 3 organic) × 3 locations]. The means averaged over all locations for fertilizer application, plant protection products application, transportation, harvesting, labor, machinery, fuels, plant protections products and tools energy inputs, total energy inputs, outputs (grapes), outputs (grapes + shoots), grape yield, man hour, pomace and ethanol from pomace were significantly higher in conventional than in organic vineyards, while the opposite occurred for the pruning. Means averaged over two farming systems for harvesting, tools energy inputs, energy outputs (grapes), grape yield, pomace and ethanol from pomace were significantly higher at location A, followed by location C and location B. Finally, for irrigation, the means averaged over the two farming systems were significantly lower at location C. Greenhouse gas emissions were significant lower in organic than in conventional vineyards. The results show a clear response of energy inputs to energy outputs that resulted from the farming system and location.     

Energy use patterns and econometric models of major greenhouse vegetable productions in Iran

This paper examines the energy use patterns and energy input-output analysis of major greenhouse vegetable productions in Iran. Data from 43 farmers were obtained using a face-to-face questionnaire method. The majority of farmers in the surveyed region were growing cucumber and tomato. Total input energy was found to be 141493.51 and 131634.19 MJ ha⁻¹ for cucumber and tomato productions, respectively. Among input energy sources, diesel fuel and fertilizers contained highest energy with 54.17-49.02% and 21.64-24.01%, respectively. The energy ratio was found to be 0.69 and 1.48 for cucumber and tomato productions, respectively. Econometric model evaluation showed the impact of human labor for cucumber and chemicals for tomato was significant at 1% levels. Sensitivity analysis indicated that the MPP value of energy inputs were between −5.87 and 7.74. RTS (returns to scale) values for cucumber and tomato yields were found to be 1.29 and 0.76; thus, there prevailed an IRS of cucumber for estimated model. The net return was found positive, as 22651.13 and 78125.08 $ ha⁻¹ for cucumber and tomato, respectively. The benefit-cost ratios from cucumber and tomato productions were calculated to be 1.68 and 3.28, respectively. Among the surveyed greenhouses, the result indicated tomato cultivation was more profitable.     

Energy crop production costs in the EU

The objective of this study was to calculate indicative ranges of production costs and assess the main sources of cost for a number of energy crops, both annual and perennial, on a regional level in Europe. The production costs were calculated in terms of the economic compensation required by the farmer in order to grow the crop, and therefore include not only the cost of cultivation, but also the costs of land and risk, which are often omitted in production cost calculations. The cost of land was calculated as the opportunity cost based on the production of cereals. Thus, higher food prices lead to higher land costs, which in turn lead to higher energy crop production costs. The analysis was performed for three cases with different assumptions concerning yields and production cost reductions resulting from scale (total cultivation area in the region), and learning effects. The calculated energy crop production costs were found to be consistently lowest for short-rotation coppice (SRC) crops and highest for annual straw crops. The production costs of SRC crops were calculated to be about 4–5 € GJ⁻¹ under present conditions and 3–4 € GJ⁻¹ under improved future conditions. The production costs for perennial grasses were calculated to be about 6–7 € GJ⁻¹ and 5–6 € GJ⁻¹ under present and improved future conditions, respectively. The production costs for annual straw crops were estimated to be 6–8 € GJ⁻¹ under present conditions with small potential for cost reductions in the future.     

Energy intensities and greenhouse gas emission mitigation in global agriculture

Energy efficiency and greenhouse gas emissions are closely linked. This paper reviews agricultural options to reduce energy intensities and their impacts, discusses important accounting issues related to system boundaries, land scarcity, and measurement units and compares agricultural energy intensities and improvement potentials on an international level. Agricultural development in recent decades, while increasing yields, has led to lower average energy efficiencies when comparing the 1960s and the mid 1980s. In the two decades thereafter, energy intensities in developed countries increased, but with little impact on greenhouse gas emissions. Efficiency differences across countries in the year 2000 suggest a maximum improvement potential of 500 million tons of CO₂ annually. If only below average countries would increase their energy efficiency to average levels of the year 2000, the resulting emission reductions would be below 200 million tons of CO₂ annually.

Energy and associated greenhouse gas emissions from household appliances in Malaysia

Today, electricity is an indispensable key for civilization and development. The trend of electricity consumption is rather escalating. Electricity generation principally depends upon fossil fuels. In one hand, the stocks of these fuels have been confirmed to be critically limited. On the other hand, in process of electricity generation by means of these fuels, a number of poisonous by-products adversely affect the conservation of natural eco-system. Further, electricity driven appliances use emanate anti-environmental gases that also affect human health and climate. Therefore, estimation of energy consumption for operating household appliances, savings of energy under policy intervention, and emission of poisonous gases in a fast developing country deserve academic attention.     

Comparison of energy inputs in glasshouse double crop (fall and summer crops) tomato production

The study examines energy use patterns and the relationship between energy inputs and yield for double crop (fall and summer) glasshouse tomato production in Antalya province, where is one of the most important greenhouse centres in Turkey. The data of the study was retrieved from 37 fall and 25 summer glasshouse tomato producers via face to face survey in 2007. The research findings revealed energy use values for inputs such as manure, electricity, chemical fertilizer and fuel. While the average yield per hectare is 25025.4 kg for enterprises involved in tomato production in fall, it is 22392.9 kg for summer production. The overall energy consumption is higher in fall production with 81362.2 MJ ha^?1 in comparison to summer production 63023.2 MJ ha^?1. In addition, the specific energy requirement is 3521.2 MJ t^?1 and 2814.4 MJ t^?1 for fall and summer production in order and the energy efficiency was found out to be 0.31 kg MJ^?1 and 0.36 kg MJ^?1 respectively. Finally, the energy relationship was tested using the production relationship. The findings indicated that direct energy sources are effective in tomato yield for both of the two seasons. More clearly, the most significant energy input was electrical energy for summer production and a combination of electrical energy, human power and machinery for fall production. Yet, excess and unconscious use of chemical ingredients in glasshouse tomato production was confirmed as energy derived from chemical drugs leaded a declination in the yield for fall season. Therefore, the paper revealed energy relationship for double crop glasshouse tomato production in Antalya, being a reference for similar production methodologies.     

Energy and the long cycles

The hypothesis is submitted in this paper that energy — directly or indirectly - had much more to do with the generation of the long Kondratiev cycles than generally recognized. An attempt is made to test this and it is suggested that the next upturn may also be energy-related.     

Oil and natural gas prices and greenhouse gas emission mitigation

The hikes in hydrocarbon prices during the last years have lead to concern about investment choices in the energy system and uncertainty about the costs for mitigation of greenhouse gas emissions. On the one hand, high prices of oil and natural gas increase the use of coal; on the other hand, the cost difference between fossil-based energy and non-carbon energy options decreases. We use the global energy model TIMER to explore the energy system impacts of exogenously forced low, medium and high hydrocarbon price scenarios, with and without climate policy. We find that without climate policy high hydrocarbon prices drive electricity production from natural gas to coal. In the transport sector, high hydrocarbon prices lead to the introduction of alternative fuels, especially biofuels and coal-based hydrogen. This leads to increased emissions of CO₂. With climate policy, high hydrocarbon prices cause a shift in electricity production from a dominant position of natural gas with carbon capture and sequestration (CCS) to coal-with-CCS, nuclear and wind. In the transport sector, the introduction of hydrogen opens up the possibility of CCS, leading to a higher mitigation potential at the same costs. In a more dynamic simulation of carbon price and oil price interaction the effects might be dampened somewhat.     

Energy and greenhouse gas emission effects of corn and cellulosic ethanol with technology improvements and land use changes

Use of ethanol as a transportation fuel in the United States has grown from 76 dam³ in 1980 to over 40.1 hm³ in 2009 — and virtually all of it has been produced from corn. It has been debated whether using corn ethanol results in any energy and greenhouse gas benefits. This issue has been especially critical in the past several years, when indirect effects, such as indirect land use changes, associated with U.S. corn ethanol production are considered in evaluation. In the past three years, modeling of direct and indirect land use changes related to the production of corn ethanol has advanced significantly. Meanwhile, technology improvements in key stages of the ethanol life cycle (such as corn farming and ethanol production) have been made. With updated simulation results of direct and indirect land use changes and observed technology improvements in the past several years, we conducted a life-cycle analysis of ethanol and show that at present and in the near future, using corn ethanol reduces greenhouse gas emission by more than 20%, relative to those of petroleum gasoline. On the other hand, second-generation ethanol could achieve much higher reductions in greenhouse gas emissions. In a broader sense, sound evaluation of U.S. biofuel policies should account for both unanticipated consequences and technology potentials. We maintain that the usefulness of such evaluations is to provide insight into how to prevent unanticipated consequences and how to promote efficient technologies with policy intervention.     

Geothermal contribution to greenhouse heating

Plant freezing and plant-growth inhibition are among the major problems in greenhouse cultivation in the central part of Argentina. The possibility of using a constant temperature underground geothermal water source, which flows naturally, has been studied as an economic option to solve these problems. A system of heating by means of geothermal energy, with energy-conservation measures, was designed and evaluated for typical production greenhouses in the southern part of Córdoba, Argentina. The results of tests carried out during 3 years are presented. These results are really promising, taking into account the high benefit/cost relation of the design and the availability of similar geothermal resources in many farms of this region.     

Reduce energy use and greenhouse gas emissions from global dairy processing facilities

Global butter, concentrated milk, and milk powder products use approximately 15% of annual raw milk production. Similar to cheese and fluid milk, dairy processing of these products can be energy intensive. In this paper, we analyzed production and energy data compiled through extensive literature reviews on butter, concentrated milk, milk and whey powder processing across various countries and plants. Magnitudes of national final and primary specific energy consumption (SEC) exhibited large variations across dairy products; in addition, the final SEC of individual plants and products exhibited significant variations within a country and between countries. Furthermore, we quantified national energy intensity indicators (EIIs) accounting for dairy product mixes and technological advancement. The significant variations of SEC and EII values indicate a high degree of likelihood that there is significant potential for energy savings in the global dairy processing industry. Based upon the study samples, we estimate potential energy savings for dairy processing industry in selected countries, and estimates annual reduction of 9–14 million metric-ton carbon-equivalent¹ could be achieved if measures are implemented to lower SEC values by 50–80% in half of global dairy plants. The paper calls for publication of more energy data from the dairy processing industry.     

Energy balance and greenhouse gas emissions from the production and sequestration of charcoal from agricultural residues

Agricultural residues (wheat/barley/oat straw) can be used to produce charcoal, which can then be either landfilled off-site or spread on the agricultural field as a means for sequestering carbon. One centralized and five portable charcoal production technologies were explored in this paper. The centralized system produced 747.95 kg-CO₂eq/tonne-straw and sequestered 0.204 t-C/t-straw. The portable systems sequestered carbon at 0.141–0.217 t-C/t-straw. The net energy ratio (NER) of the portable systems was higher than the centralized one at 10.29–16.26 compared to 6.04. For the centralized system, the carbon sequestration and the cumulative energy demand were most sensitive to the charcoal yield. Converting straw residues into charcoal can reduce GHG emissions by 80% after approximately 8.5 years relative to the baseline of in-field decomposition, showing these systems are effective carbon sequestration methods.