Regional specialization and market integration: agroecosystem energy transitions in Upper Austria

We investigate agroecosystem energy flows in two Upper Austrian regions, the lowland region Sankt Florian and the prealpine region Grünburg, at five time points between 1830 and 2000. Energetic agroecosystem productivity (energy contents of crops, livestock products, and wood per unit area) is compared to different types of energy inputs, i.e., external inputs from society (labor, industrial inputs, and external biomass inputs) and biomass reused from the local agroecosystem (feed, litter, and seeds). Energy transfers between different compartments of the agroecosystem (agricultural land, forest, and livestock) are also quantified. This allows for delineating an agroecosystem energy transition: In the first stage of this transition, i.e., in the nineteenth century, agroecosystem productivity was low (final produce ranged between 14 and 27 GJ/ha/yr), and local biomass reused made up 97% of total energy inputs in both regions (25–61 GJ/ha/yr). In this period, agroecosystem productivity increase was achieved primarily through more recycling of energy flows within the agroecosystems. In the second stage of the agroecosystem energy transition, i.e., after World War II, external energy inputs increased by factors 2.5 (Sankt Florian) and 5.0 (Grünburg), partly replacing local energy transfers. Final produce per area increased by factors 6.1 (Sankt Florian) and 2.9 (Grünburg). The difference in the resulting energy returns on investment (EROI) owes to regional specialization on cropping versus livestock rearing and to increasing market integration. Our results suggest that sustainable land-use intensification may benefit from some regional specialization harnessing local production potentials based on a mix of local and external inputs.

     

Energy and land use in worldwide agriculture: an application of life cycle energy and cluster analysis

Agriculture is expected to provide food in a sustainable manner while also partially contributing to the energy problem as well as to bio-material supply. Moreover, fossil fuels scarcity calls for an increase of energy efficiency in agricultural processes. This study evaluates patterns, trends, driving factors and trade-offs of energy use in selected agricultural systems and aims at grouping them into clusters with similar energy and social performances. Results show that in 2010 the highest power densities and energy intensities of production are found by crop sector of cluster 5 (China: 59.19 GJ/ha, 15.29 MJ/kg dm) and cluster 3 (Japan: 50.11 GJ/ha, 12.32 MJ/kg dm) as well as by livestock sector of cluster 3 (Japan: 328.47 GJ/ha, 103.08 MJ/kg dm), while the lowest values in clusters 2 and 4, including selected developing countries and USA. Cluster 3 (Japan) also shows the lowest energy intensity of economic value of crops (2.75 MJ/$), while cluster 5 (China) the highest one (23.96 MJ/$). Cluster analysis also sheds light on trends, identifying two groups: cluster 1*, gathering most European countries, USA and Japan, characterized by a decreasing trend of all energy indicators; and cluster 2*, including developing countries, the Netherlands and Spain, characterized by an increasing trend of indicators. Results highlight the importance of an integrated framework for evaluating energy use as well as of a multi-criteria approach to understand the trade-offs and interplay of performance indicators.     

Impact of policies favouring organic inputs on small farms in Karnataka, India: a multicriteria approach

Over 56% of the population of Karnataka state in India depends on agriculture for its livelihood. A majority of these are small and marginal farmers, with land under 2?ha, responsible for nearly half the food production in the state. The increasing rate of farmers’ suicides in the state is reportedly fuelled among others, by increasing input costs, crop failure and accumulating debt. This triggered several policy measures, intended to improve the sustainability of farm livelihoods including those promoting organic practices in farming. The paper presents the results of a multicriteria analysis conducted to comprehend the effects of two different practice–policy scenarios on smallholders in Karnataka—one scenario ‘with policy’ (WP) to support organic agricultural practices and the other a ‘business as usual’ (BAU) scenario that continues to stress on market-based, synthetic inputs for cultivation. The paper integrates results from quantitative and participatory techniques to compare and project effects on ecological, economic and socio-cultural indicators. Ecological and economic indicators in WP are projected to be significantly higher than BAU in a majority of the study sites, while socio-cultural indicators show mixed outcomes, depending on regional and social characteristics. Across the study sites, small and rain-fed farms are benefitted better in WP compared to large and irrigated farms, respectively. Among small and rain-fed farms, soil fertility, water quality, agro-diversity, net income and freedom from indebtedness improve considerably, while there is slight reduction in collective activities and no perceivable change in land-based subsistence.     

Assessing the impact of policy-driven agricultural practices in Karnataka, India

The classical approach of assessing sustainability with respect to its three underlying pillars, ecological, economic, and social, is adopted in this paper, with an added emphasis on estimating the simultaneous effects of each pillar on the other two. The paper assesses the impact of policy-driven changes in cultivation practices in five districts in the south-western Indian state of Karnataka. A comparative statics analysis using a simultaneous equations model is developed to capture the stability of each pillar into the future and their concurrent interactive impacts and trade-offs. Ecological and economic impacts of policies favoring organic farming are estimated to be uniformly significant and positive in the study districts. However, the impact on socio-cultural criteria is subjective to the eco-regional context. Cost savings, through producing organic inputs on-farm, maximizes synchrony among the three pillars vis-à-vis sourcing these inputs from the market. With more reliance on organic inputs, better prospects are estimated for small and rain-fed farms compared to large and irrigated farms.     

The energy consumption of Paris and its supply areas from the eighteenth century to the present

Since the eighteenth century and the industrial revolution, cities have experienced great changes in their metabolism, and particularly in their energy consumption: transitions from one energy source to another, growing per capita consumption, and total consumption to cite but a few. These changes also impact urban energy supply areas and supply distance. This paper estimates Paris??s energy demand in both final and primary terms since the eighteenth century and gives an illustration of long-term socio-ecological interactions in an interdisciplinary perspective, connecting energy flow analysis, and historical research. It gives an overview of energy supply areas and assesses the distance between supply sites and the city. Paris??s annual total energy requirement (TER) was about 19?GJ per capita at the beginning of the eighteenth century and reached 30?GJ per capita in 1800; the supply area remained nearly the same with an average supply distance (D_avg) of 200?km. During the nineteenth century, Paris??s population increased fivefold, and energy transitioned from biomass to fossil fuel. Per capita TER remained stable, whereas Paris??s supply area moved progressively toward coal basins, in connection with the tremendous change in transport systems. As a consequence, the D_avg grew to 270?km around 1870. During the twentieth century, and especially since the Interwar period, per capita TER increased considerably (to 26?GJ/cap/year in 1910, 47?GJ/cap/year in 1946 and 126?GJ/cap/year in 2006). The internationalization of the energy supply and the shift to petroleum and natural gas also increased the remoteness of the supply sites: the D_avg equaled 3850?km in 2006.     

Quantitative assessment of the Japanese “local production for local consumption” movement: a case study of growth of vegetables in the Osaka city region

This study aimed to assess Japan’s recent “local production for local consumption” (LPLC) movement, with a special focus on vegetables in the Osaka city region of central Japan. After collecting statistics and spatial data, we conducted a multi-scale analysis of vegetable production and consumption along with the associated energy consumption, using geographical information system software at three spatial scales along the vegetable flow paths: national, regional, and local. Vegetables consumed in the Osaka city region came from prefectures throughout Japan, and we mapped the foodshed within this region at 1-km spatial resolution, as well as the distribution of farmland, farmers’ and other markets. We also conducted a scenario analysis for reduced energy consumption through organic farming and the utilization of abandoned farmland near a city to replace food imports from distant areas. We found that the large majority of vegetables consumed in the Osaka city region currently come from remote prefectures, and that this is associated with a high level of energy consumption. Inside the Osaka city region, peri-urban vegetable farming contributes to regional vegetable provision, resulting in an approximately 70 % production/consumption ratio within an 80-km radius of the urban center; if all of the area of abandoned farmland were restored to production, this ratio would increase to approximately 75 %. Organic farming activities that bring together farmers and urbanites are emerging in many parts of the study area, contributing to increased LPLC. Scenario analysis suggested that a decrease of more than 1 × 10⁶ GJ of energy inputs could be achieved through wider adoption of local organic farming for local consumption and complete utilization of abandoned farmland in the Osaka city region.     

Energy conservation and waste utilization in the cement industry serve the green technology and environment

The cement industry is one of the most energy-intensive industries consuming 4 GJ/ton of cement, i.e. 12–15% of the energy use in total industry. Energy cost accounts for 30% of the total cost of cement production. Seventy-five per cent of this energy is due to the thermal energy for clinker production. It is also found that 35% of this supplied thermal energy is lost in flue gas streams. Most modern kilns use pet coke or coal as their primary fuel. Instead, the municipal waste in landfills offer a cheap source of energy and reduce the environmental effects of dumping solid waste. The calcination and drying processes and the kiln need large quantities of thermal energy. About 40% of the total energy input is lost in the hot flue gases and cooling the stack plus the kiln shell. Hence, it is suitable to use an organic Rankine cycle (ORC) to recover the exhaust energy from the kiln. Alternatively, a 15 MW gas turbine engine combined with a steam turbine could be utilized. It was found that ORC produces 5 MW with a capital cost recovery period of 1.26 years. However, the gas turbine combined system produces 21.45 MW with a maximum recovery period of 2.66 years.     

Costs of the Wastewater Standard in Pig Production in Mexico

The objective of this article is to address the environmental costs of pig farms in the La Piedad region Mexico, through an analysis of the standard on wastewater discharges to national water bodies. Field work was carried out from April to September 1999; a survey was conducted on 23 farms and samples of wastewater were taken on 11 farms. Pig production is the third most important system in Mexican livestock production. Heterogeneity in production systems, dependence on imported inputs (genetics and feed grains), and weak internalization of environmental costs are the main characteristics of pig production in Mexico. With no specific environmental regulations on intensive livestock activities at the municipal or state levels, Mexican Official Standard 001 on wastewater discharges is the only environmental obligation that pig farms must meet. Standard 001 on wastewater contains the maximum permissible limits for 20 contaminant parameters, and is based on a cost-benefit analysis that points to secondary treatment for the regulation’s economic viability. Investment in treatment systems and the fees that pig producers must pay when they fail to comply with the limits stipulated in the regulation, are estimated assessed as an approach to environmental costs. In order to remain within the limits in the standard, pig farms must invest in tertiary treatment, and that makes meeting the standard unaffordable for this sector.     

Exploitation of renewable energy resources for environment‐friendly sustainable development in Saudi Arabia

The recent increase in energy costs, driven by a surge in oil prices, has increased world‐wide efforts on the exploitation of renewable/wind energy resources for environment‐friendly sustainable development and to mitigate future energy challenges. Moreover, experience in the wind energy industry has reached high levels in the field of manufacturing and application. This inevitably increases the merits of wind energy exploitation. In order to exploit wind resources, through the establishment of wind power plants, specific attention must be focused on the characteristics of wind and wind machines. The literature indicates that wind‐energy resources are relatively better along coastlines. In the present study, long‐term hourly mean wind speed data for the period 1986–2003, recorded at Dhahran (Eastern Coastal region, Saudi Arabia), has been analysed to examine the wind characteristics including (but not limited to): yearly/monthly/diurnal variations of wind speed, frequency distribution of wind speed, impact of hub‐height/machine‐size on energy production, etc. Data have been checked/validated for completeness. Data analysis indicated that long‐term monthly average wind speeds ranged from 3.8 to 5.8 m/s.

Concurrently, the study determined monthly average daily energy generation from different sizes of commercial wind machines (150, 250, 600 kW, etc.) to assess the impact of wind machine size on energy yield. The study also estimated annual energy production (MWh/year) from wind farms of different capacities (3, 6, 12, 24 MW, etc.) by utilising different commercial wind energy conversion systems (WECS). It was observed that, for a given 6 MW wind farm size, a cluster of 150 kW wind machines (at 50 m hub‐height) yielded about 32% more energy when compared to a cluster of 600 kW wind machines. The study also estimated the cost of wind‐based electricity (COE, US$/kWh) by using different capacities of commercial WECS. It was found that the COE per kWh is 0.045 US$/kWh for 150 kW wind machine (at 50 m hub‐height) whereas COE was 0.039 US$/kWh for 600 kW wind machine (at 50 m hub‐height). The study also dealt with wind turbine characteristics (such as capacity factor and availability factor). These characteristics are important indicators of wind turbine performance evaluation.     

江苏农村地区能源消费与可持续发展

江苏是中国经济发展较为迅速的省份 ,为了研究农村地区经济发展过程中能源消费的变化规律 ,本文在大量调查数据分析的基础上 ,对江苏农村地区乡镇工业、农村生活和农业生产能源消费水平和结构及其发展变化进行了研究 ,提出了农村地区能源问题的可持续发展战略     

利用CFSR数据开展海上风电场长年代风能资源评估

开展长年代风能资源评估可为海上风电场的可行性研究和风险评估提供依据和支撑。创新性地引入了气候预测系统再分析(CFSR)数据,以江苏响水海上风电场为例开展了长年代风能资源评估,结果表明:CFSR数据10 m高度风速与海上气象塔10 m高度风速的平均偏差为-0.2 m·s~(-1),均方根误差为1.9 m·s~(-1);CFSR数据10 m高度风速与海上气象塔90 m高度风速的相关系数范围在0.359~0.619,相比气象站的相关系数提高了40%~90%;长年代订正得到海上气象塔90 m高度近30 a的风数据,多年平均风速为6.9 m·s~(-1),标准差为0.2 m·s~(-1)(2.9%);测算出海上风电场近30年的等效满负荷小时数,多年平均值为2 423 h,标准差为112 h(4.6%);评估出25 a一遇(海上风电场的寿命期)、10 a一遇、5 a一遇的最小年平均风速分别为6.6、6.7和6.8 m·s~(-1),最小年等效满负荷小时数分别为2 227、2 280和2 329 h。利用CFSR数据开展海上风电场长年代风能资源评估在技术上是可行的。     

新疆能源强度影响因素及其治理策略

在发展低碳经济的趋势下,新疆过高的能源强度成为其自身发展和全国节能工作的"短板",会给我国的节能减排工作造成越来越难以解决的障碍,因此新疆面临严峻的节能减排挑战。能源强度(单位GDP能耗)是一个地区能源综合利用效率指标,受到多方面因素的影响。本文编制了1992、1997、2002和2007年新疆30部门能源投入产出表,采用投入产出结构分解方法(SDA),全面并深入分析GDP变动、单位产出能耗(即直接能源消耗系数)、技术变动和最终需求(包括消费规模、消费结构、投资规模、投资结构和净出口)变动对新疆生产能源强度的影响效应,并基于节能降耗角度分析技术变动和最终需求对产业结构变动的影响效应。结果表明:1992-2007年技术变动、消费规模、消费结构、投资规模和投资结构均对新疆生产能源强度的降低起抑制作用,并推动了产业结构中低能耗部门比重的下降。最后结合测算结果与新疆资源经济的特殊性,从技术投入、投资与消费引导以及民生扶持等方面提出了新疆能源强度治理策略建议。     

Energy consumption analysis of ABS plastic parts injected in a hybrid injection moulding machine

The energy analysis of injection moulding processes is influenced by complex interactions amongst the moulded part, its material, the injection machine, the process parameters and the environmental conditions. The availability of energy usage analyses that comprehend information on specific materials and machine kind is limited. This paper reports a study that estimates and analyses the power usage profile (PUP), the specific energy consumption (SEC), and the energy distribution at an operation level of two different injected parts made of acrylonitrile-butadiene-styrene and produced in a hybrid injection moulding machine. The methodology followed by the authors incorporates an experiment carried out in an industrial facility. A large sample size, and data-acquisition and data post-processing processes to obtain an accurate PUP and SEC are used. A breakdown of the energy consumed by the injection moulding process of the parts studied at an operation level using Sankey diagrams is discussed. The study results are used to identify strategies to reduce the energy consumed by the processes. The methodology employed, and the strategies reported could be used with other plastic parts regardless of the material and machine used. The results reported are new experimental data useful input for theoretical models.     

Recent Changes in Land-Use in the Pambala–Chilaw Lagoon Complex (Sri Lanka) Investigated Using Remote Sensing and GIS: Conservation of Mangroves vs. Development of Shrimp Farming

Shrimp aquaculture is currently one of the major threats to mangroves, their destruction causing both environmental and social problems. This study investigated the mangrove area in the Pambala–Chilaw Lagoon complex (07°30 N, 079°49 E) in Sri Lanka. Using air-borne remote sensing, a land-use map was constructed in a geographical information system of the study area and pond managers were interviewed about the functioning of their shrimp farms. Based on fieldwork during the four years after taking the aerial photographs, an updated GIS-based land-use map was constructed and compared the original situation. This revealed that shrimp farms had expanded with by 25 ha in four years, mainly at the expense of mangrove forest (approx. 13 ha) and coconut plantations (approx. 11 ha). Official documents from the World Conservation Union advise conservation of the undisturbed habitats in Pambala, but this study's observations do not corroborate an eventuation of this. Other authors reported political patronage as the main cause of this adverse situation. Since the shrimp industry depends on various ecological services provided by the mangrove ecosystem in order to maintain production (cf. ecological footprint concept) the mangrove destruction is counter-productive and these observations are therefore alarming for the aquaculturists as well. The low ratio (2.6 : 1) of remaining mangrove to shrimp pond area suggests that the industry may experience severe problems, particularly as mangrove areas continue to be reclaimed for aquaculture or other land uses, unless drastic measures are taken.     

美国居民生活用能状况与趋势:30年微观调查数据分析

随着居民部门用能快速增长,各国都在致力于观察本国居民能源消费特征以减少碳排放,特别是发达国家。本文应用近30年的微观调查数据分析美国居民能源消费现状和趋势,为发展中国家提供一些借鉴意义。从总量上看,伴随着人口、家庭数量和建筑面积的上升,能源消费总量变化较小,趋于稳定;人均用能则呈下降趋势。从用能结构来看,以天然气和电力为主,2009年分别占比44%和41%;近30年来天然气占比小幅下降,电力占比上升明显;完善的天然气设施和电力服务体系使得能源可获得性高。从用途分类来看,取暖和家电占绝大比例,2009年分别占比41%和35%;取暖用能近30年来出现平缓下降趋势,燃料来源70%是天然气;家电设备用能占比明显上升,增长近1倍;制冷占比较小,近年出现小幅上升;热水用能则比较稳定。家庭炊事燃料以电力和天然气为主,2009年分别占比60%和34%。近30年,家用电器保有量和能源效率有显著提高。建筑用能方面,美国房屋服务时间长,后期建筑房屋在保温性能方面高于早期房屋,单位面积耗能下降。美国居民享受着较高水平的能源服务,能源消费总量在近30年没有明显变化,这和能源效率的提高有着密切关系;如完善的"能源之星"项目是一个强有力的措施,以及完善的能源统计制度为能源分析提供了有力的数据支撑。相比,中国存在居民炊事用能固体燃料占比较高、建筑服务周期短、建筑材料耗能比重大等问题。建议中国政府进一步完善能源统计制度、推行农村能源扶持项目和能源标识、加强建筑规划、落实建筑能耗标准。     

Applying Agroecology to Enhance the Productivity of Peasant Farming Systems in Latin America

The great majority of farmers in Latin America are peasants who still farm small plots of land, usually in marginal environments utilizing traditional and subsistence methods. The contribution of the 16 million peasant units to regional food security is, however, substantial. Research has shown that peasant systems, which mostly rely on local resources and complex cropping patterns, are reasonably productive despite their land endowments and low use of external inputs. Moreover analysis of NGO-led agroecological initiatives show that traditional crop and animal systems can be adapted to increase productivity by biologically re-structuring peasant farms which in turn leads to optimization of key agroecosystem processes (nutrient cycling, organic matter accumulation, biological pest regulation, etc.) and efficient use of labor and local resources. Examples of such grassroots projects are herein described to show that agroecological approaches can offer opportunities to substantially increase food production while preserving the natural resource base and empowering rural communities.     

A simplified method for the design and sizing of anaerobic digestion systems for smaller farms

Anaerobic digestion (AD) as a waste treatment practice has existed for nearly 200 years and has become an accepted option for many farming and small-scale residential operations. Many developing countries now encourage the use of AD in order to meet new environmental regulations and/or to provide small amounts of energy resulting from methane generated during the process. This development has been met with some difficulty due to the lack of resources and knowledge of the systems in many of the rural communities in which these digesters are placed. A properly designed AD system can help prevent soil and water pollution as well as help mitigate methane emissions by capturing them for use as a potential energy source. This paper focuses on providing guidance to the proper design and sizing of an AD system for typical small farms, which account for the majority of dairy farms worldwide. A focus was on the implementation of such systems as they might be applied in Central America, although the aspects studied here can be applied for AD systems handling animal waste streams practically anywhere. We provide a method for sizing of anaerobic digester systems based on design standards from the US National Resource Conservation Service and using field sampled data of holding pen wash water runoff. An overview of the decision process for alternative designs is given, and simple-to-use nomographs are presented for use in sizing of an anaerobic digester system for smaller (non-industrial)-scale farms.     

Prediction of primary energy demand in China based on AGAEDE optimal model

In this article,we present an application of Adaptive Genetic Algorithm Energy Demand Estimation(AGAEDE) optimal model to improve the efficiency of energy demand prediction.The coefficients of the two forms of the model(both linear and quadratic) are optimized by AGA using factors,such as GDP,population,urbanization rate,and RD inputs together with energy consumption structure,that affect demand.Since the spurious regression phenomenon occurs for a wide range of time series analysis in econometrics,we also discuss this problem for the current artificial intelligence model.The simulation results show that the proposed model is more accurate and reliable compared with other existing methods and the China's energy demand will be 5.23 billion TCE in 2020 according to the average results of the AGAEDE optimal model.Further discussion illustrates that there will be great pressure for China to fulfill the planned goal of controlling energy demand set in the National Energy Demand Project(2014—2020).