生物质能发电电价的敏感因素分析

通过设定电价敏感度和电价下降系数两个分析参数，对加工废弃物发电、秸秆发电、沼气发电和垃圾发电等4大类生物质能发电技术的电价敏感性因素进行了定量分析。分析结果显示．发电时间和固定资产为影响4类生物质能发电电价的主要敏感因素，其中固定资产通过规模化降低成本后会带来电价的减少。而原料成本仅对秸秆发电技术的影响较大。     

波浪发电系统专用水轮机的优化设计

文章结合青岛某地的波浪发电系统,研发了一种新型的超低比转速混流式水轮机。通过对水轮机全流道进行三维定常不可压缩湍流流场的数值模拟,分析了不同导叶、不同出水边叶片转轮及不同尾水管锥度对水轮机性能的影响,在满足某地波浪发电系统设计的要求下,通过数值模拟的方式,设计出合适的波浪发电系统专用水轮机。模拟计算结果表明:在设计转速为180 r/min时,水轮机出力和效率均满足波浪发电系统的要求;在设计工况下,尾水管内涡与尾水管中心线接近同轴,确保了水轮机的运行稳定性;在全年波高的变化范围内,设计的波浪发电水轮机具有良好的水力特性和运行稳定性,适合波浪发电波动大的特点。     

基于混沌飞蛾捕焰算法的波浪发电系统最大功率跟踪

针对水动力参数非线性导致直驱式波浪发电系统控制效果不佳问题,文章采用混沌飞蛾捕焰优化控制算法解决。该算法初期引入具有非周期性和遍历性的混沌算子,采用多精英组合的直线捕焰模式寻优;后期结合火焰自适应机制,采用螺旋捕焰方式,求解最优电磁力,控制直线发电装置,提高捕获效率。通过ANSYS软件进行浮子的水动力数值计算,结合改进算法寻求系统最优负载。仿真结果表明,在波浪周期变化时,混沌飞蛾捕焰算法能有效提高全局搜索能力和求解精度,增加系统输出功率。     

Electricity generation from renewable energy : The French experience

Besides its traditional and large scale involvement in hydro power, EDF has recently taken a significant interest in “new” renewable energy sources. The present paper describes the reasons and the field of application of this interest.     

一种基于弹簧振子的波浪发电装置

通过对波浪发电的现状、发展趋势以及波浪的特性进行分析,提出了一种采用弹簧振子作为动子的直线发电装置。通过对该装置自身结构进行简化分析并对其建立数学模型;根据线性波理论给出的波浪力与时间的关系建立数学模型的微分方程;在对该微分方程进行拉普拉斯(laplace)变换整理后再进行拉普拉斯反变换,得到发电机的动子与定子相对位移随时间的变化关系,进而得到发电装置的发电功率,并选取参数采用matlab软件进行仿真模拟,绘制位移-时间图和P-c-k关系曲线。结果表明,在设计参数下装置发电功率可达到78.6 W。     

Electricity generation from sediment microbial fuel cells with algae-assisted cathodes

One major limiting factor for sediment microbial fuel cells (SMFC) is the low oxygen reduction rate in the cathode. The use of the photosynthetic process of the algae is an effective strategy to increase the oxygen availability to the cathode. In this study, SMFCs were constructed by introducing the algae (Chlorella vulgaris) to the cathode, in order to generate oxygen in situ. Cyclic voltammetry and dissolved oxygen analysis confirmed that C. vulgaris in the cathode can increase the dissolved oxygen concentration and the oxygen reduction rate. We showed that power generation of SMFC with algae-assisted cathode was 21 mW m⁻² and was further increased to 38 mW m⁻² with additional carbon nanotube coating in the cathode, which was 2.4 fold higher than that of the SMFC with bare cathode. This relatively simple method increases the oxygen reduction rate at a low cost and can be applied to improve the performance of SMFCs.     

Electricity generation from rice straw using a microbial fuel cell

This study demonstrated electricity generation from rice straw without pretreatment in a two-chambered microbial fuel cell (MFC) inoculated with a mixed culture of cellulose-degrading bacteria (CDB). The power density reached 145 mW/m² with an initial rice straw concentration of 1 g/L; while the coulombic efficiencies (CEs) ranged from 54.3 to 45.3%, corresponding to initial rice straw concentrations of 0.5–1 g/L. Stackable MFCs in series and parallel produced an open circuit voltage of 2.17 and 0.723 V, respectively, using hexacyanoferrate as the catholyte. The maximum power for serial connection of three stacked MFCs was 490 mW/m² (0.5 mA). In parallelly stacked MFCs, the current levels were approximately 3-fold (1.5 mA) higher than those produced from the serial connection. These results demonstrated that electricity can be produced from rice straw by exploiting CDB as the biocatalyst. Thus, this method provides a promising way to utilize rice straw for bioenergy production.     

新型海岸波浪发电装置的设计与分析

提出一种由发电机、蓄电装置、增速齿轮组、主轴、多组组件组成的利用波浪能发电的装置。多组组件安装在主轴上,每一组件包括弹簧外卡环、扭转弹簧、卷筒棘轮机构、浮子、绳子和定滑轮,当浮子随波浪上下浮动时,卷筒正反转,扭转弹簧提供卷筒反转的力,利用棘轮机构的单向运动特性、多组组件及增速齿轮组保证电机主轴连续单向高速旋转,达到发电目的。卷筒是该装置的主要受力部件,文中对其建立了有限元模型、进行了受力计算及边界条件的确定,应用simulation进行有限元分析,结果表明,对于给定的条件,卷筒刚度和强度均满足要求。     

Thermoelectric power generation from biomass cook stoves

The use of biomass cook stoves is widespread in the rural communities of developing countries. It is important to improve the efficiency of these stoves in order to reduce the global warming contribution. An improved biomass fired stove has been developed in our laboratory and a prototype has been built. The combustion chamber is designed to achieve the almost complete combustion of wood thus increasing the efficiency and decreasing indoor air pollution.     

Electricity and potable water from a solar tower power plant

The cogeneration of electricity and potable water utilising solar energy is studied, assuming solar tower power plants with the open volumetric PHOEBUS receiver. The results for alternative plant configurations show that the water production cost is about the same or even lower than the cost of water produced by conventionally fired systems. Furthermore, the integration offers a reduction of CO₂-emissions related to the water production of up to 50%, additionally to the environmental benefits of solar electricity production.     

Electricity generation using a carbon-dioxide thermosiphon

There is an opportunity to expand the baseload geothermal electricity generation capacity through the development of engineered geothermal systems (EGS). Carbon dioxide (CO₂) could be used as an alternative to water to extract heat from these systems considering its advantages of ease of flow through the geothermal reservoir, strong innate buoyancy that permits the use of a thermosiphon rather than a pumped system over a large range of fluid flow rates, and lower dissolution of materials that lead to fouling. However, the thermodynamics of EGS using CO₂ to extract heat from subsurface rock masses is not well understood. Here we show that the wellbore frictional pressure losses are the dominant factor in CO₂-based EGS. Wellbore friction is the major limiter on the amount of energy that can be extracted from the reservoir by CO₂, as measured by the exergy available at the surface. The result is that CO₂ is less effective at energy extraction than water under conditions similar to past EGS trials. Nevertheless, CO₂ can perform well in lower permeability reservoirs, or if the wellbore diameter is increased. Our results demonstrate that CO₂-based EGS need to be designed with the use of CO₂ in mind. We suggest this work to be a starting point for analysis of the surface infrastructure and plant design and economics of CO₂-based EGS.     

Economic analysis of power generation from floating solar chimney power plant

Solar chimney thermal power technology that has a long life span is a promising large-scale solar power generating technology. This paper performs economic analysis of power generation from floating solar chimney power plant (FSCPP) by analyzing cash flows during the whole service period of a 100 MW plant. Cash flows are influenced by many factors including investment, operation and maintenance cost, life span, payback period, inflation rate, minimum attractive rate of return, non-returnable subsidy rate, interest rate of loans, sale price of electricity, income tax rate and whether additional revenue generated by carbon credits is included or not. Financial incentives and additional revenue generated by carbon credits can accelerate the development of the FSCPP. Sensitivity analysis to examine the effects of the factors on cash flows of a 100 MW FSCPP is performed in detail. The results show that the minimum price for obtaining minimum attractive rate of return (MARR) of 8% reaches 0.83 yuan (kWh)^?1 under financial incentives including loans at a low interest rate of 2% and free income tax. Comparisons of economics of the FSCPP and reinforced concrete solar chimney power plant or solar photovoltaic plant are also performed by analyzing their cash flows. It is concluded that FSCPP is in reality more economical than reinforced concrete solar chimney power plant (RCSCPP) or solar photovoltaic plant (SPVP) with the same power capacity.     

Performance study of power density in PEMFC for power generation from solar energy

A study has been carried-out on power density in the Proton Exchange Membrane Fuel Cell (PEMFC) for its application for solar power generation. It involves a fuel cell approach assisted with specific electro-catalysts to process special chemical coupling (2-propanol/acetone/H₂) for generating the power. This knowledge will be useful for designing the solar power generation system based on this special chemical coupling enabling to use low-grade solar heat (<100 °C). For this purpose, a wide study has been conducted in the PEMFC using different catalytic electrodes at various orientations (0°, 45° and 90°). The investigations were carried-out at different temperatures from 45 °C to 60 °C using liquid oxidant mixtures in different proportions. The maximum power density attained was 1.78 mW cm^?2 at 60 °C. The PEMFC based technique for solar power generation may prove to be a promising option to harness this everlasting source of sun’s energy in the coming future.     

Ocean wave power

The wave energy arriving on the west coast of the United Kingdom represents a very substantial energy resource, amounting on average to more than twice the present installed capacity of the Central Electricity Generating Board. Recent comprehensive studies by the CEGB^1,2 and the National Engineering Laboratory³ suggest that although there is no obvious technical reason for being unable ultimately to harness much of this energy, and many methods have been proposed, there are still considerable uncertainties over the choice of wave power system and its economics. Wave power does show sufficient promise however to have been made the subject of serious studies supported by the CEGB and the Department of Energy.⁴In this paper the potential of wave power and some of the more promising methods of harnessing it are discussed, together with an appreciation of some of the many technical and engineering problems which still need to be examined, and a discussion of the impact of wave power on the environment. By considering the results of recent research and their impact on wave power economics it is argued that wave power could be exploited to conserve fossil fuels, but is unlikely to be competitive with nuclear power.     

Superconducting power generation

With respect to the electric power industry, the superconducting AC generator has the greatest potential for large-scale commercial application of superconductivity. Such a machine should be able to convert mechanical energy to electric energy more efficiently and with greater economy of weight and volume than any other method. These advantages can be accrued at a scale of 1200 MVA output, with the added potential of operation at transmission line voltage and greater system stability. In the past, a great deal of R&D was done in this area, but the present industry trend to smaller machines has decreased this effort. Though the advantages diminish at the much smaller scale of 250 MVA, such machines still offer interesting possibilities. Superconducting synchronous generators with a superconducting adjustable field rotor keep power losses to a minimum since the field in the stator is phase-locked in synchronism with the rotating rotor field. The high magnetic flux density produced by a superconducting rotor field winding permits a great reduction in the amount of iron required in both the rotor and stator. This reduction introduces degrees of freedom not previously possible in generator or motor design. This article is written to help better perceive the technological potential of new developments     

鹰式波浪能发电装置发电系统研究

文章首先对鹰式波浪能发电装置能量转换系统进行分类,分析了各系统的组成及工作原理,设计了一种液压式和直驱式组合的发电系统,通过模型试验优化了系统中的参数配置,提高了能量转换效率,最后通过实海况试验验证了"鹰式一号"波浪能发电装置的发电系统设计方案的可行性。     

地热发电

＠张启电能清洁卫生，使用方便，但电能只是一种能量形式，需要由其它能量转换得到。例如，有从煤和油转换成电的火力发电；有从水力转换成电的水力发电；有从核能转换成电的核电，等等。近年来，环境问题受到高度重视，从可持续发展考虑，新能源利用越来越显示出优越性，随之新...