Determination of the optimal quantity of crop residues for energy in sugarcane crop management using linear programming in variety selection and planting strategy

The aim of this work was to present organizational models for optimizing the reduction of crop residue generated by the sugarcane culture. The first model consisted of the selection of varieties of sugarcane to be planted meeting the mill requirements and, at the same time, to minimize the quantity of residue produced. The second model discussed the use of residue to produce energy. This is related to the selection of variety and quantity to be planted, in order to meet the requirements of the mill, to reduce the quantity of residue, and to maximize as much as possible the energy production. The use of linear programming was proposed. The two models presented similar results in this study, and both may be used to define the varieties and areas to be cultivated.     

Preliminary identification of potential markets for off-grid electrification: tool development and a case study of Ghana

With more than one billion people lacking access to electricity in the world, ensuring universal access to electricity by 2030 remains a major challenge which cannot be left to the government initiatives alone. Access to local information and identification of potential areas for investment can be a challenge for investors. This paper provides a tool for preliminary assessment of potential markets for off-grid electrification in developing countries and applies this to Ghana to demonstrate its applicability. A multi-criteria approach is used to rank the districts according to the overall potential and the best markets and least favourable areas for investment are identified. The tool offers flexibility to include new inputs to the analysis and the factor weights can be adjusted as appropriate. The case study shows that the tool can effectively identify potential areas from a list of candidates and offers support to analysts.     

Evaluation of the impact of access to electricity: A comparative analysis of South Africa,China, India and Brazil

Most developing countries include rural electrification programs in their efforts to improve social conditions. There are, however, several obstacles to the evaluation of such programs and therefore of their social, economic, environmental and energy impacts on the target population, particularly on impoverished communities located in remote areas. Evaluation of the efficacy of public policies aimed at rural electrification in South Africa, China, India and Brazil enables such actions to be quantified and re-considered so as to bolster the sustainability of their planning and implementation and also so as to enable comprehension of the significance of access to electricity in relation to other aspects of the drive to improve living standards. The provision of electric energy amounts to more than access to a public service and should be considered an essential right, in a context of social equity and justice, which permits social integration and the access to other equally essential services.     

防锈工作三要素

在现代化机械加工行业中,防锈工作日趋重要。提高防锈工作效率,主要应该从根据产品的性能选择正确的防锈材料、安排完整正确的防锈工艺、严格防锈管理三方面入手。正确选择金属加工中所需清洗剂、防锈剂,并使防锈工艺规范化、完整化,保证防锈材料能够充分发挥其性能。同时要有专业的防锈科技人员指导,各级人员严格遵守防锈管理规范,从而使防锈工作发挥其最大功用。     

Energy and the World Summit on Sustainable Development: what next?

Given the importance of energy issues to sustainable development, energy was a priority issue at the World Summit on Sustainable Development in August 2002. The objective of this paper is to examine the outcomes of the Summit on energy, and to assess them against proposals to address the lack of access to modern energy and the need to move toward a cleaner energy system. We find that lack of political leadership from key countries prevented agreement not only on targets for renewable energy, but also on a programme to promote access. The achievements of the Summit were limited to enabling activities such as capacity building and technology transfer, rather than substantive agreements. While WSSD put energy higher on the agenda than before, no institutional home or programme to take the issues forward has emerged. This therefore remains a critical challenge to be addressed. Achieving this broad goal will require building a coalition to promote cleaner energy, and committing resources to programme for energy access. Based on analysis of proposals and the negotiations, we propose several key areas where progress is still possible and necessary, including: shifting more international public and private energy financing toward access investments and cleaner energy investments, advancing regional approaches to access and renewable energy targets, and a range of mechanisms to strengthen institutional capacity for integrating energy and sustainable development.     

全面建设小康社会的能源保障问题

到2020年我国将建成小康社会,按照保守的估计人均能源消费量将达到2toe,全国将达到近30亿toe。综观国内能源资源条件,国内能源供应将面临潜在的总量短缺,尤其是石油、天然气供应将面临结构性短缺。为应对挑战需要采取以下对策:调整和优化能源结构,建立可持续能源保障体系;发展洁净煤技术,减少能源利用对环境的影响;优先发展水电,提高水电在能源消费结构中的比例;大力促进新能源和可再生能源的发展;给核能发电应有的地位,达到能源消费总量的1/10;坚持节能和提高能源利用效率;多元化利用国际油气资源,规避能源风险;建立以石油储备为主的能源战略储备体系,保障能源安全。     

Historical energy price shocks and their changing effects on the economy

The purpose of this paper is to identify the changes in the impact of energy shocks on economic activity — with an interest in assessing if an economy's vulnerability and resilience to shocks improved with economic development. Using data on the United Kingdom over the last three hundred years, the paper identifies supply, aggregate demand and residual shocks to energy prices and estimates their changing influence on energy prices and GDP. The results suggest that the impacts of supply shocks rose with its increasing dependence on coal, and declined with its partial transition to oil. However, the transition from exporting coal to importing oil increased the negative impacts of demand shocks. More generally, the results indicate that improvements in vulnerability and resilience to shocks did not progress systematically as the economy developed. Instead, the changes in impacts depended greatly on the circumstances related to the demand for and supply of energy sources. If these experiences are transferable to future markets, a transition to a diversified mix of renewable energy is likely to reduce vulnerability and increase resilience to energy price shocks.     

The prerequisite for competition in the restructured wholesale Saudi electricity market

Protection of customers against monopoly is the first and main objective of the Saudi Electricity and Co-generation Regulatory Authority (ECRA). The second important objective, as recommended by the present study, is regulating natural monopoly businesses [Saudi electricity national grid (SENG) and Saudi electricity distribution (SED)] in addition to promoting real competition in competitive businesses [power supply providers (PSPs) and customer service providers (CSPs)]. Another four main objectives of ECRA are to promote the efficient use of energy and natural resources, to ensure a reasonable rate of return for PSPs and CSPs and at the same time to be fair to end-users, to ensure reasonable charges to SENG and SED services to be adequate for them to run the organization in a break-even manner and to maintain the system's security and reliability. The present paper discusses the way to improve and restructure the Saudi electricity market.     

Transport fuel for the post-oil era — a different view

In the March 1978 issue of Energy Policy, G. Charlesworth and T.M. Baker published an article on future transport fuels. Of the two principal alternatives to petroleum-based fuels — electricity and coal-derived liquids — the authors chose to devote primary attention to electricity and to the implications of a shift from heat engines to battery electric vehicles. The purpose of the article below is not to refute their findings, but to point out that their conclusions apply only to the UK and to countries with similar resource bases (such as other European countries and Japan). Changes in automotive engine design and in the fuels to power motor vehicles are likely to have a very different effect in countries such as the USA and Brazil. This paper addresses the outlook for motor fuels in the USA.     

基于首次及后备判别的柔性直流线路保护方法

高速可靠的保护技术对柔性直流系统(VSC-HVDC)的发展和应用具有重要意义.当前后备保护会因主保护失灵、拒动和误动等而触发,后备保护工作意味着保护系统切除故障的时间加长,不利于电力系统稳定.针对这一问题,文章以辐射状网络的柔性直流双极系统为例,根据故障保护的特点,提出利用首次判别保证速动性以及后备判别来避免因主保护拒...     

Implications of energy use for fishing fleet—Taiwan example

Commercial fisheries rely heavily on fossil fuel combustion and contribute heavily to the emission of atmospheric pollutants and greenhouse gases. Propulsion output of fishing vessels has continually increased from 30 kW in 1959 to nearly 320 kW in 2000, indicating that the Taiwanese fishing fleet tended to voyage farther and faster, and to adjust for the heavier loads demanded by more powerful fishing gear. Daily emissions from Taiwanese fishing vessels were estimated using output method. The marine fishery is unlikely to grow in the future as the government is implementing measures to ensure the development of sustainable fishing practices. There has been a rising trend in pollution to production ratios during the study period between 1959 and 2008. The ratio increased by 47% in the first decade, followed by fluctuations within the range of 50%–58% for the remainder of the statistical period. There is a need to investigate the possibility of reductions in all categories of fishing with regard to energy use and emissions through the subsidization of fishing vessels to encourage operators to switch to more energy efficient equipment and cleaner fuels.     

Making concentrated solar power competitive with coal: The costs of a European feed-in tariff

The European Union has yet to determine how exactly to reach its greenhouse gas emissions targets for the future. One potential answer involves large-scale development of concentrated solar power (CSP) in the North African region, transmitting the power to Europe. CSP is a relatively young and little utilized technology and is expensive when compared to other methods of generation. Feasibility studies have shown it is possible to generate enough power from CSP plants in Africa to spearhead the EUs climate goals. However, the costs of such a project are less well known. Currently, CSP must compete with low cost coal-fired electricity plants, severely hindering development. We examine the possible investment costs required for North African CSP levelized electricity cost to equal those of coal-fired plants and the potential subsidy costs needed to encourage growth until the technologies reach price parity. We also examine the sensitivity of investment and subsidies to changes in key factors. We find that estimates of subsidy amounts are reasonable for the EU and that sensitivity to such factors as perceived risk and learning rates would enable policy-makers to positively influence the cost of subsidies and time required for CSP to be competitive with coal.     

促进风电产业健康发展的思考

文章对制约风电发展的因素进行了分析,认为,我国应大力发展小规模、低电压、近消纳、直接接入配电网系统的分散式风电,积极开展大规模集中开发风电的研究,待时机成熟时再全面推开。国家应当用好政府补贴、特许权招标两个手段,加强对风电的调控。合理确定各地风电规模,统筹考虑风电电源布局,加强风电配套电网建设,改革风电项目审批或核准方式,取消行政办法对风电上网的定价。推广实施节能发电调度办法,确保优先调度已建成运行的风电上网。通过竞争使风电招标的上网价格尽快达到常规电力的水平,具备与普通商业电力相同的竞争力。     

Linking consumer energy efficiency with security of supply

Most modern energy policies seek to achieve systematic ongoing incremental increases in consumer energy efficiency, since this contributes to improved security of supply, favourable environmental outcomes and increased economic efficiency. Yet realised levels of efficiency are typically well below the most cost-effective equilibrium due to variety of behavioural and organisational barriers, which are often linked to information constraints. In addition efficient users are normally unrewarded for collective benefits to system security and to the environment, thus reducing the incentives for energy consumers to invest in efficiency improvements. This paper examines the dichotomies and symmetries between supply- and demand-side solutions to energy security concerns and reviews opportunities to overcome barriers to improved consumer efficiency. A security market is identified as a mechanism to promote both demand- and supply-side investments that support electricity system security. Such a market would assist in setting the optimal quantity of reserves while achieving an efficient balance between supply- and demand-side initiatives. It would also help to smooth overall investment throughout the energy system by encouraging incremental approaches, such as distributed generation and demand-side alternatives where they provide competitive value. Although the discussion is applicable to energy systems in general, it focuses primarily on electricity in New Zealand.     

Reactive power control of wind farms for voltage control applications

In the last few years, there is a strong trend towards decentralised production and supply, leading to a situation where a growing number of small and medium size producers will be connected to energy networks. But at the same time, the power quality of the generation must be ensured and this means that the electrical parameters of the distribution network have to be maintained within their upper and lower limits. Therefore, new problems related to the management and operation of energy transfer and distribution and to the efficient distribution of renewable energy in the grids are actually arising. Hence, it is reasonable to think that dispersed generation (wind energy generation in this paper) should start to take part in the control of electric variables, and in particular, in reactive power control which is directly related to the voltage level control of distribution networks. This paper presents a control strategy developed for the reactive power regulation of wind farms made up with double fed induction generators, in order to contribute to the voltage regulation of the electrical grid to which farms are connected.     

汽泵启停机组技术在350MW机组上的应用

分析国电九江发电厂5#机组使用电动给水泵(简称电泵)启停机组存在的缺点及无法使用汽动给水泵(简称汽泵)启停机组的原因,对驱动给水泵汽轮机(也称小汽轮机)的低压供汽系统和给水系统进行了改造。实现了机组能使用汽泵启停机组。4次使用汽泵启停机组节约厂用电27万kWh。     

Who governs energy? The challenges facing global energy governance

This article conceptualizes the energy problems facing society from a global governance perspective. It argues that a notion of “global energy governance,” taken to mean international collective action efforts undertaken to manage and distribute energy resources and provide energy services, offers a meaningful and useful framework for assessing energy-related challenges. The article begins by exploring the concepts of governance, global governance, and global energy governance. It then examines some of the existing institutions in place to establish and carry out rules and norms governing global energy problems and describes the range of institutional design options available to policymakers. It briefly traces the role of a selection of these institutions, from inter-governmental organizations to summit processes to multilateral development banks to global action networks, in responding to energy issues, and points out their strengths and weaknesses. The article concludes by analyzing how the various approaches to global governance differ in their applicability to addressing the conundrums of global energy problems.     

Policy redesign for solving the financial bottleneck in demand side management (DSM) in China

DSM is one of the best and most practical policy tools for China to balance environmental protection and economic growth. However, the bottleneck lies in the lack of long-term, stable, sufficient and gradually increasing funds to flow into DSM projects. The author redesigns the practical ‘system benefit charge (SBC)’ policy, which will provide long-term and stable funding for DSM, the policy to facilitate the financial support from banking sector and capital market, and investigates the possibility of DSM funding from CDM projects. SBC is the best way to boost long-term stable and sufficient funding for DSM at present in China. The current low inflation rate and natural resource price are favored to expedite the implementation of SBC and DSM developments. With regard to the uneven development, China needs to design relative policies to offset the impact in different areas, such as tax reduction and fiscal subsides. It is time for China to develop a definite and clear target and timetable to implement DSM, which will give the public and enterprises a definite and clear expectation for the future. The government should publicize a clear and integrated DSM development plan and relative policy outline in the near, medium, and long term.     

Conversion of the UK gas system to transport hydrogen

One option to decarbonise residential heat in the UK is to convert the existing natural gas networks to deliver hydrogen. We review the technical feasibility of this option using semi-structured interviews underpinned by a literature review and we assess the potential economic benefits using the UK MARKAL energy systems model. We conclude that hydrogen can be transported safely in the low-pressure pipes but we identify concerns over the reduced capacity of the system and the much lower linepack storage compared to natural gas. New hydrogen meters and sensors would have to be fitted to every building in a hydrogen conversion program and appliances would have to be converted unless the government was to legislate to make them hydrogen-ready in advance.     

Fractional yield and moisture of corn stover biomass produced in the Northern US Corn Belt

Corn stover is an ideal biomass feedstock but the harvest and storage of this material present many challenges. Information on the fractional yield and moisture of stover grown and collected in the Upper Midwest during the typical grain harvest period was used to estimate the expected yield and moisture when utilizing various harvesting methods. At grain harvest, the ratio of stover to total crop dry mass averaged 48% and approximately 15%, 8%, 21%, and 56% of the total stover dry mass resided in the cob, husk, leaf, and stalk fractions, respectively. Total stover moisture ranged from 66% to 47% when grain moisture was less than 30%. The stalk moisture ranged from 69% to 56%, 63% to 45%, 52% to 32%, and 36% to 27% for the whole, top-three-quarters, top-half, and top-quarter of the stalk, respectively. The total stover:grain moisture ratio averaged 2.15:1. A single-pass stover and grain harvester that would collect the cob and husk plus the top-half, top-three-quarters or the entire stalk (and similar fraction of the leaves) was estimated to harvest 46%, 72%, and 100% of the available stover at a range of moistures from 49% to 33%, 57% to 38%, and 64% to 48%, respectively. Another single-pass stover and grain harvester that would collect the bottom half of the stalks, 50% of the top half of the stalk and 50% of the leaves was estimated to harvest 60% of the available stover at a range of moistures from 69% to 55%.