中国风能发展战略研究

2008年2月中国工程院启动中国能源中长期(2030、2050)发展战略研究重大咨询项目,项目设置6个课题,根据可再生能源课题的安排,风能组的工作是在"中国可再生能源发展战略研究"的基础上,进一步摸清风能资源家底,从战略的角度对风能市场、产业、技术和应用进行综合分析,提出我国风能中长期发展的战略目标、技术路线、发展重点和政策措施。文章简要介绍了研究的结果。     

Reliability evaluation of generating systems containing wind power and energy storage

Global environmental concerns associated with conventional energy generation have led to the rapid growth of wind energy in power systems. Many jurisdictions around the world have set high wind penetration targets in their energy generation mix. Wind speed is variable in nature, and power output from a wind farm is not readily controllable. High wind penetration can lead to high-risk levels in power system reliability and stability. In order to maintain the system stability, wind energy dispatch is usually restricted and energy storage is considered to smooth out the fluctuations and improve supply continuity. The benefits from using energy storage are highly dependent on the operating strategies associated with wind and storage in the power system. A simulation technique that can consider wind farm and energy storage operating strategies is presented. Different operating strategies are compared and the resulting benefits are evaluated. The system impacts of energy storage capacity and operating constraints, wind energy dispatch restrictions, wind penetration level and wind farm location on the reliability benefits from energy storage are illustrated.     

Wind energy

From its rebirth in the early 1980s, the rate of development of wind energy has been dramatic. Today, other than hydropower, it is the most important of the renewable sources of power. The UK Government and the EU Commission have adopted targets for renewable energy generation of 10 and 12% of consumption, respectively. Much of this, by necessity, must be met by wind energy. The US Department of Energy has set a goal of 6% of electricity supply from wind energy by 2020. For this potential to be fully realized, several aspects, related to public acceptance, and technical issues, related to the expected increase in penetration on the electricity network and the current drive towards larger wind turbines, need to be resolved. Nevertheless, these challenges will be met and wind energy will, very likely, become increasingly important over the next two decades. An overview of the technology is presented.     

Foundations for offshore wind turbines

An important engineering challenge of today, and a vital one for the future, is to develop and harvest alternative sources of energy. This is a firm priority in the UK, with the government setting a target of 10% of electricity from renewable sources by 2010. A component central to this commitment will be to harvest electrical power from the vast energy reserves offshore, through wind turbines or current or wave power generators. The most mature of these technologies is that of wind, as much technology transfer can be gained from onshore experience. Onshore wind farms, although supplying 'green energy', tend to provoke some objections on aesthetic grounds. These objections can be countered by locating the turbines offshore, where it will also be possible to install larger capacity turbines, thus maximizing the potential of each wind farm location. This paper explores some civil-engineering problems encountered for offshore wind turbines. A critical component is the connection of the structure to the ground, and in particular how the load applied to the structure is transferred safely to the surrounding soil. We review previous work on the design of offshore foundations, and then present some simple design calculations for sizing foundations and structures appropriate to the wind-turbine problem. We examine the deficiencies in the current design approaches, and the research currently under way to overcome these deficiencies. Designs must be improved so that these alternative energy sources can compete economically with traditional energy suppliers.     

Evaluation of current status and future directions of wind energy in India

Wind energy is the fastest growing electricity generation technology. During the last decade of the 20th century, grid-connected wind capacity worldwide has doubled approximately every 3 years. Climate change is a major challenge to sustainable development worldwide and is increasingly recognized by forward-looking political and business leaders. One of the tasks we are facing is a profound transformation of our energy system over the next few decades of replacing fossil fuels with renewable energies and dramatically increasing energy efficiency. At present, wind energy is receiving considerable attention in the world. In this study, development of wind energy system and the potential of wind energy in India have been investigated. This paper presents the progress made by wind energy in the recent years, and discusses the potential of this technology. The aim of the work is to investigate the wind energy plants and projects in India. It can be concluded from this analysis that wind energy utilization in India and throughout world has sharply increased.     

Sell or store? An ADP approach to marketing renewable energy

In deregulated markets, electricity is usually traded in advance, and the advance commitments have a time lag of several periods. For example, in the German intraday market, the seller commits to providing electricity 45 min before the 15-min interval in which delivery has to be made. We consider the problem of a producer that generates energy from stochastic, renewable sources, such as solar or wind and uses a storage device with conversion losses. We model the problem as a Markov Decision Process and consider lagged commitments for the first time in the literature. The problem is solved using an innovative approximate dynamic programming approach. Its key elements are the analytical derivation of the optimal action based on the value function approximation and a new combination of approximate policy iteration with classical backward induction. The new approach is quite general with regard to the stochastic processes describing the energy production and price evolution. We demonstrate the application of our approach by considering a wind farm/storage combination. A numerical study using real-world data shows the applicability and performance of the new approach and investigates how the storage device’s parameters influence profit.     

Energy policy shifts towards sustainable energy future for Malaysia

As a developing country, Malaysia’s prosperity and welfare depends heavily on having access to reliable and secure supplies of energy. As a result, the country’s future energy requirements have become a policy priority in recent years. Energy is essential for human life, and a secure and accessible supply of energy becomes important for the modern societies. Fossil fuels such as coal, oil, and natural gas are currently the world’s primary energy sources and continue to provide energy source to the world. These energy sources have depleted in reserves in recent years and they can also cause irreparably damage to the environment such as global warming and climate change. These environmental concerns can be addressed, to some extent, through more sustainable solutions such as the use of renewable energy resources. In Malaysia, the economic and environmental impacts of fossil fuels use have become hard to ignore. The government has introduced and implemented policy measures to address concerns surrounding the use of fossil fuels and to promote energy efficiency and renewable energy use. In this paper, we review the historical evolution of Malaysian energy policies and initiatives designed to secure diverse energy sources and avoid over-reliance on fossil fuels. In recent years, Malaysia has been catching up with global call to shift to renewable energy use and is now putting a focus on renewable energy in its future energy mix. The paper also discusses challenges and concerns over the future of sustainable energy of the country.     

Assessing the impact of marine wind farms on birds through movement modelling

Advances in technology and engineering, along with European Union renewable energy targets, have stimulated a rapid growth of the wind power sector. Wind farms contribute to carbon emission reductions, but there is a need to ensure that these structures do not adversely impact the populations that interact with them, particularly birds. We developed movement models based on observed avoidance responses of common eider Somateria mollissima to wind farms to predict, and identify potential measures to reduce, impacts. Flight trajectory data that were  collected post-construction of the Danish Nysted offshore wind farm were used to parameterize competing models of bird movements around turbines. The model most closely fitting the observed data incorporated individual variation in the minimum distance at which birds responded to the turbines. We show how such models can contribute to the spatial planning of wind farms by assessing their extent, turbine spacing and configurations on the probability of birds passing between the turbines. Avian movement models can make new contributions to environmental assessments of wind farm developments, and provide insights into how to reduce impacts that can be identified at the planning stage.     

Determinants of household use of energy-efficient and renewable energy technologies in rural Ethiopia

The poor households living in low-income countries depend on traditional sources for basic energy service; which has a broader socio-economic and environmental adverse effect. To mitigate the problem policy measures were used to increase access to energy-efficient and renewable energy technology. However, there are few studies on demand-side particularly on the drivers of household joint technology adoption behavior. Against this backdrop, this paper examined the determinants of household behavior concerning the adoption decision of energy-efficient and renewable energy technology using cross-sectional data collected from 195 households in central Ethiopia. For identification, the generalized ordered probit model which is a more flexible discrete choice model was applied. The findings reveal that the richer the households, the more likely that they adopt both improved cookstoves and renewable energy technology because of the greater financial capacity to afford to pay the upfront cost of the technologies. Household size and assets such as landholding size and the number of cattle owned positively associated with the use of both technologies. Likewise, a high level of education attained by the head of the household likely reduces the likelihood of adoption of neither technology but increases the likelihood of adoption of renewable energy. Participation in off-farm income-earning activities likely increases the propensity to invest in renewable energy. Similarly, household membership in local cooperatives found to increase the propensity to invest in renewable energy technology. While access to credit found to increase the adoption of energy-efficient technology. The finding of this study implies that poverty reduction and education policies increase the propensity to invest in energy-efficient and renewable energy technology. Likewise, better access to credit, off-farm employment opportunities, and cooperatives are also important.     

海上风电场规划的主要影响因素分析

海上风电是新能源发展的一个战略重点,目前我国沿海地区正在积极开展大规模海上风电的规划。对中国近海风电场规划与开发现状进行了介绍,总结了近海风电场规划的主要内容,分析了近海风电场在规划中的主要影响因素和解决方法。     

风能资源开发利用的气象技术应用和发展

基于要实现科学高效地开发利用风能资源,促进我国从风能大国向风能强国发展,针对风能资源开发利用过程中的气象技术应用,依据过去大量的项目实践、数据分析和相关测试试验结果,归纳总结了气象技术在我国风能资源开发利用各环节的应用现状、存在问题及其对项目效益可能产生的影响;在分析大气科学的相关原理和风电产业发展对气象技术应用的特殊需求基础上,提出了风能资源测量、分析评估、数值模拟和数值预报技术应用时应注意的几个关键技术问题及其发展方向。     

Reliability analysis for wind turbines with incomplete failure data collected from after the date of initial installation

Reliability has an impact on wind energy project costs and benefits. Both life test data and field failure data can be used for reliability analysis. In wind energy industry, wind farm operators have greater interest in recording wind turbine operating data. However, field failure data may be tainted or incomplete, and therefore it needs a more general mathematical model and algorithms to solve the model. The aim of this paper is to provide a solution to this problem. A three-parameter Weibull failure rate function is discussed for wind turbines and the parameters are estimated by maximum likelihood and least squares. Two populations of German and Danish wind turbines are analyzed. The traditional Weibull failure rate function is also employed for comparison. Analysis shows that the three-parameter Weibull function can obtain more accuracy on reliability growth of wind turbines. This work will be helpful in the understanding of the reliability growth of wind energy systems as wind energy technologies evolving. The proposed three-parameter Weibull function is also applicable to the life test of the components that have been used for a period of time, not only in wind energy but also in other industries.     

风电项目中的土木工程问题及有关研究的思考和发展展望

从配套工程建设、风况数据的搜集、整理及分析、预测等角度,探讨了促进我国风电事业的发展方式;指出关注风电建设中的土木工程问题,编制有关规范或指导手册等文件,做好风资源的普查、评估和风电场发电量预测,并在这些技术领域做到专业化、规范化,形成可靠的、成熟的、具有自主知识产权的技术体系对我国的风电发展至关重要。最后探讨了需要进行研究的方向,并结合中国国情对风电的发展做了展望。     

An overview of wind energy development and policy initiatives in India

Clean Technologies and Environmental Policy - The Indian renewable energy sector has grown at a compounded annual growth rate of 15.51% in the last five years, where wind growth is about...     

Holistic simulation of wind turbines with fully aero-elastic and electrical model

Requirements for the design of wind turbines advance facing the challenges of a high content of renewable energy sources in the public grid. A high percentage of renewable energy weaken the grid and grid faults become more likely, which add additional loads on the wind turbine. Load calculations with aero-elastic models are standard for the design of wind turbines. Components of the electric system are usually roughly modeled in aero-elastic models and therefore the effect of detailed electrical models on the load calculations is unclear. A holistic wind turbine model is obtained, by combining an aero-elastic model and detailed electrical model into one co-simulation. The holistic model, representing a DFIG turbine is compared to a standard aero-elastic model for load calculations. It is shown that a detailed modelling of the electrical components e.g., generator, converter, and grid, have an influence on the results of load calculations. An analysis of low-voltage-ride-trough events during turbulent wind shows massive increase of loads on the drive train and effects the tower loads. Furthermore, the presented holistic model could be used to investigate different control approaches on the wind turbine dynamics and loads. This approach is applicable to the modelling of a holistic wind park to investigate interaction on the electrical level and simultaneously evaluate the loads on the wind turbine.

     

Prospects for wind energy utilisation in Karnataka State

An examination of the data available at 22 meteorological stations in Karnataka State shows that wind velocities in the State as a whole are neither spectacularly high nor negligibly low. The highest winds (annual mean of around 13 km/hr) are experienced in parts of the northern maidan region of the State (Gulbarga, Raichur and Bidar districts) and in Bangalore. The winds are strongly seasonal: typically, the five monsoon months May-September account for about 80% of the annual wind energy flux. Although the data available are inadequate to make precise estimates, they indicate that the total wind energy potential of the State is about an order of magnitude higher than the current electrical energy consumption. The possible exploitation of wind energy for applications in rural areas therefore requires serious consideration, but it is argued that to be successful it is essential to formulate an integrated and carefully planned programme. The output of current windpumps needs to be increased; a doubling should be feasible by the design of suitable load-matching devices. The first cost has to be reduced by careful design, by the use of local materials and skills and by employing a labour-intensive technology. A consideration of the agricultural factors in the northern maidan region of the State shows that there is likely to be a strong need for mechanical assistance in supplemental and life-saving irrigation for the dry crops characteristic of the area. A technological target for a windmill that could find applications in this area would be one with a rotor diameter of about 10 m that can lift about 10,000 litres of water per hour in winds of 10 km/hr (2.8 m/s) hourly average speed and costs less than about Rs 10,000. Although no such windmills exist as of today, the authors believe that achievement of this target is feasible. An examination of various possible scenarios for the use of windmills in this area suggests that with a windpump costing about Rs 12,000, a three hectare farm growing two dry crops a year can expect an annual return of about 150% from an initial investment of about Rs 15,000. It is concluded that it should be highly worthwhile to undertake a coordinated programme for wind energy development that will include more detailed wind surveys in the northern maidan area (as well as some others, such as the Western Ghats), the development of suitable windmill designs and a study of their applications to agriculture as well as to other fields.     

Technology assessment for clean energy technologies: The case of the Pacific Northwest

This study presents a technology assessment for clean power generation in the Pacific Northwest. Our goal is to incorporate clean production principles into the evaluation process for power alternatives. Two types of technologies are considered: one is for a renewable energy source (wind) and the other is for a traditional, fossil fuel based energy source (coal). The Analytical Hierarchy Process is used to assess the feasibility of both the wind energy and clean burning coal energy technologies. Criteria such as location, cost, feasibility, and availability are used for evaluations. For the wind energy, cost was determined to be the most important criterion when making a technology decision. For the SO₂ emissions technology, the regenerative process was determined to be the best technology to scrub SO₂ emissions from the air. Additionally, efforts towards renewable energy in Oregon should continue. Both federal and state governments offer tax credits that can help mitigate costs and facilitate the adoption of renewable energy options for power companies.     

Development of cumulative impact assessment guidelines for offshore wind farms and evaluation of use in project making

The offshore wind energy sector in the United Kingdom (UK) has grown rapidly since the first turbine generators were installed in 2000: by 2016 there were over 1400 installed turbines with combined capacity of 5.1 GW. The sector is considered by UK Government as essential to the development of a low carbon economy and to meeting binding targets on carbon reduction and renewable energy generation. The Crown Estate, responsible for licensing development on the sea bed around the UK, has held three rounds of licensing since 2000 for wind developments. Some of the projects in the first two rounds suffered long delays due to uncertainty of project level impacts, particularly cumulative impacts. A number of key stakeholders identified a need for cumulative impact assessment (CIA) methodology to be developed that was definitive and endorsed by regulators and industry to aid unblocking barriers to delivery. This paper explores the background to the development of the guidelines and how they were ‘co-created’ with industry and regulators. We evaluate to what extent they have been used to shape and develop practice.

Abbreviations: CIA: cumulative impact assessment; EU: European Union; GW: gigawatt; MW megawatt; NERC: Natural Environment Research Council; NGO: Non Governmental Organisation; OWF: offshore wind farm; PINS: Planning Inspectorate; RED: Renewable Energy Directive; RUK: Renewables UK; SPA: Special Protection Area; TCE: The Crown Estate; TWh: terra watt hours; UK: United Kingdom.     

Analysis of concentration fluctuations in gas dispersion around high-rise building for different incident wind directions

This article presents experimental results that illustrate the unsteady characteristics of gas dispersion around a complex-shaped high-rise building for different incident wind directions. A series of wind tunnel experiments were conducted using a 1:30 scale model that represented the real structures under study. The objective of this paper is to study the behaviour of concentration fluctuations through transient analysis. Tracer gas was continuously released from a point source located at different positions, and a time series of fluctuating concentrations were recorded at a large number of points using fast flame ionization detectors. The experimental data were analysed to provide a comprehensive data set including variances and associated statistical quantities. Both the unsteady characteristics of the system and their potential practical impact are presented and discussed. Under crowd living conditions, the air pollutant exhausted from one household could probably re-enter into the neighbouring households, traveling with ambient airflow. Such pollutant dispersion process is defined as air cross-contamination in this study. The results indicate that the wind-induced cross-contamination around the studied type of high-rise building should not be overlooked, and the fluctuating concentrations should be paid attention to particularly during the evaluation of a potential contamination risk. This study can help deepen our understanding of the mechanisms of air cross-contamination, and will be useful for implementing optimization strategies to improve the built environments in metropolitan cities such as Hong Kong.     

LMI-based robust voltage tracking control for a class of renewable energy systems

This paper introduces a method of robust voltage tracking control for a class of renewable energy systems, which uses a linear matrix inequality (LMI)-based approach. A remodeling method is introduced where the nonlinear model of the renewable energy system is represented as a nonlinear combination of linear subsystems with state-dependent parameters (the so-called linear state-dependent parameter system model, LSDPM). Next, the remodeling method is applied to a boost converter, a photovoltaic (PV) system, and a wind energy conversion system as examples. A robust output voltage tracking approach is proposed based on the LSDPM. Using Lyapunov’s direct method, controller stability analyses are expressed as LMI formulations. Powerful numerical toolboxes then solve for the controller gains. The advantages of this approach include: i) the generalized remodeling technique is applicable to a wide variety of renewable energy systems; ii) it creates a unified LMI-based design framework for multiple control objectives; iii) it provides numerically solved control gains; and iv) it provides robust tracking control for the multiple objectives of renewable energy systems. Using an LMI-based robust voltage tracking controller is an accurate and effective method of control for many types of renewable energy systems. Finally, practical DSP-based experiments are carried out using the buck converter as an example. The satisfactory results of these experiments verify the theoretical derivations for this control method.