Feasibility of Iceland/United Kingdom HVDC submarine cable link

The authors address: market considerations, including forecasts for the development of electricity supply in the United Kingdom with cost of electricity from new plant; investments for the development of hydro resources in Iceland, supply of submarine cables, overhead transmission lines, and rectifier/inverter plant; marine environment, installation of cables, and cable repair; rectifier/inverter station equipment; high-voltage direct-current (HVDC) overhead transmission lines; and overall availability of the link. It is shown that: there should be no major difficulties in the manufacture and laying of submarine cables of the length and type necessary for the link; the availability of the connection should be at least equal to that of a new coal or nuclear plant; and the cost of energy delivered would be very competitive with that from new coal or nuclear power stations     

Geothermal electric power in Iceland: Development in perspective

Geothermal energy is extensively used in thermal (direct) applications in Iceland. More than 70% of the total population enjoy geothermal district heating. Hydro-power provides most of the electricity generated in Iceland, with less than 10% of the potential harnessed. Iceland is well endowed with both geothermal (high- and low-temperature) and hydro-power resources. At the end of 1980, the installed geothermal power in Iceland was 818 MW₁ in direct applications and 41 MW_e in electric power generation. This exploitation represents a few percent of the estimated geothermal resources of Iceland. Plans to develop geothermal electric power in Iceland date back to the early 1960s. The first geothermal electric power plant (3 MW_e) was installed in 1969. In recent years, several small-scale (two 1 MW_e and one 6 MW_e) geothermal power units have been installed in a cogeneration plant for district heating purposes. There is one major (30 MW_e) geothermal electric power plant in Iceland, which became operational in 1978. Hydro-power, geothermal energy and oil provide consumers in Iceland with about 18, 38, and 44% of their energy needs, respectively.     

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...     

Economies of scale in electricity generation in the United Kingdom

The investment programme of the Central Electricity Generating Board (CEGB) since the late nineteen fifties has been predicated in principle on economies of scale and has been largely based in practice on 500 MW(e) turbine generator sets. This paper compares the strategy adopted by the CEGB with alternative hypothetical strategies based on smaller units of plant. Simulation of the supply system over ten years suggests that the economies of scale in very large plant have not been sufficient to offset the attendant disadvantages. Allowance is made for the variation with capacity of the capital cost, thermal efficiency, construction time, planning margin and availability. It is concluded that better results might have been obtained with sets between 200 MW(e) and 300 MW(e). It is acknowledged that this post hoc analysis has only an indirect connection with the decisions that now face the CEGB. the potential economics of scale in nuclear stations are not of the same form as those in fossil fuelled stations. There are also unsatisfactory aspects of the analysis which leave some uncertainty about the validity of the conclusions. But what the analysis does show is that there are conditions where economies of scale are outweighed by other factors, that these conditions are not especially remarkable, that they seem to have been satisfied by the CEGB system and that supply utilities in developing countries, where comparable decisions have now to be taken and where the disadvantages of scale are more pronounced, should examine carefully the case for large generating units in local circumstances.     

光伏发电在我国电力能源结构中的战略地位和未来发展方向

前 言 在可再生能源的家族中，资源量最大、分布最普遍的是太阳能，事实上，其它可再生能源也间接来自于太阳能。全球权威能源机构预测，到本世纪中期太阳能将成为人类能源构成中的重要组成部分，而到本世纪末太阳能将成为人类能源构成中的主要部分。我国陆地表面每年接受太阳辐射能相当于约49000亿tce（标准煤），全国三分之二的国土面积年日照在2200小时以上，年太阳辐射量超过5000焦／米^2（相当于170千克标准煤／米^2），太阳能资源丰富，是中华民族赖以生存，永续繁衍的最宝贵的资源。     

地热发电:蕴藏丰富 前景广阔

作为可再生能源的一员,地热能资源丰富。我国藏滇地热带有高温地热资源分布,可用于地热蒸汽发电;中低温地下热水直接利用的能量居世界第一,其中的温度较高者,可以先发电,再将尾水作综合利用。我国已开始干热岩地热资源发电领域的研究。     

Evaluation of the flat-plate solar collector system for electric power generation

The simplest method of utilizing the energy of the sun to generate electric power is to use a flat-plate collector system. Flat-plate collectors have no tracking mechanism, make use of both direct and diffuse radiation, have no focusing arrangements and are less costly per square foot than parabolic trough collectors, paraboloid of revolution collectors or heliostats. The main disadvantage to the flat-plate collector system is the relatively low temperatures reached by the collector surface ( 300°F maximum).This evaluation of the flat-plate collector system was designed to determine the number of flat-plate collectors required to generate a given amount of electricity with optimum efficiency. Variable parameters are the temperature of the heat transport fluid, both to and from the collector field. In the analysis, the efficiency of the flat-plate collectors was coupled to the efficiency of the thermal cycle to calculate optimal overall system effeciencies. Overall system efficiencies for the system are on the order of 3·5 per cent or less. Over two million 4 ft by 4 ft collectors would be required to produce 100,000 kW(e).Based on the results of this analsis, it can be shown that the limiting factor in the use of the flat-plate collector system for electric power generation is the efficiency of the collectors. An increase in the overall system efficiency can occur only if the collector efficiency can be increased at the higher surface tempertures.     

Equity and electric power generation facility location in California

An alternative to cost/benefit analysis for analyzing the equity of electric power generation facility location, utilizing the potential for air quality degradation, is developed and applied to California. Siting issues motivating disagreement on facility location are reviewed. Equity concepts are introduced, and their implementation is discussed. Several measures for assessing the equity of facility location are proposed, and the equities of existing facility locations in California are analyzed for each measure. Equity considerations for future siting decisions are examined.     

Geothermal energy potential for power generation in Turkey: A case study in Simav,Kutahya

Geothermal energy and the other renewable energy sources are becoming attractive solutions for clean and sustainable energy needs of Turkey. Geothermal energy is being used for electricity production and it has direct usage in Turkey, which is among the first five countries in the world for the geothermal direct usage applications. Although, Turkey is the second country to have the highest geothermal energy potential in Europe, the electricity production from geothermal energy is quite low. The main purpose of this study is to investigate the status of the geothermal energy for the electricity generation in Turkey. Currently, there is one geothermal power plant with an installed capacity of 20.4 MWe already operating in the Denizli–Kizildere geothermal field and another is under the construction in the Aydin–Germencik field.This study examines the potential and utilization of the existing geothermal energy resources in Kutahya–Simav region. The temperature of the geothermal fluid in the Simav–Eynal field is too high for the district heating system. Therefore, the possibility of electrical energy generation by a binary-cycle has been researched and the preliminary feasibility studies have been conducted in the field. For the environmental reasons, the working fluid used in this binary power plant has been chosen as HCFC-124. It has been concluded that the Kutahya–Simav geothermal power plant has the potential to produce an installed capacity of 2.9 MWe energy, and a minimum of 17,020 MWh/year electrical energy can be produced from this plant. As a conclusion, the pre-feasibility study indicates that the project is economically feasible and applicable.     

Infrastructure roots. Evolution of electric power in the United States

Electricity holds a unique place in the US infrastructure. It is a commodity, a technology, and a necessity. Electric utilities must walk a fine line to balance each of these aspects. While electricity is a commodity that may be bought and sold, it must also be regulated to remain affordable for the general population. Reliability is continually balanced against the cost of upgrades and maintenance. This paper discusses the interconnection of regional area power systems in the US and the benefits such interconnection brings.     

基于大规模风、光并网外送需求的高压直流混合式直流断路器研究

全控型器件的直流断路器作为风电、光伏直流外送通道的关键设备,存在成本高、耐短路电流能力差等问题。文章提出了一种基于晶闸管和IGBT全桥子模块串联的新型混合直流断路器拓扑结构,其固态部分由大量晶闸管和少量IGBT全桥子模块串联构成,降低了器件成本和送出通道建设成本,同时借助全桥子模块,晶闸管可以在反向电压的作用下快速关断。最后仿真验证了新型直流断路器的分断性能。     

Mobilising for marine wind energy in the United Kingdom

Since 2000, the United Kingdom has enthusiastically adopted marine wind energy as a potentially major source of electricity production and has become the leading nation in terms of output. This is in contrast to its relatively poor attainment of wind energy on land, and raises questions about the reasons for this difference in performance. This article traces the phases of development of marine wind energy in the UK with reference to factors that are instrumental in the uptake of this form of renewable energy. A number of features emerge from this analysis that stand in some contrast to the situation on land and help to explain the UK's current status. These include: recognition of an exceptional resource and relative ease of exploitation; government commitment and policy geared to controlled growth and strategic oversight, adequate economic support and start-up investment; the unusual rights and interests of the Crown Estate; and growing scale, confidence and organisation on the part of the industry. Set against these factors are the complexities of consenting, supply bottlenecks, and some stakeholder and public resistance, though these are outmatched by the drivers in favour of development and are being partly addressed.     

Design of electric power generation systems using waste heat energy

The recent energy crisis forces engineers to take into account reduction of electricity consumption as well as heat energy consumption in industry. As it is very difficult to save the amount of electricity, they have tried to recover electric power using waste heat energies. In this paper, the possibilities of electric power recovery from waste heat energies are discussed based on the relationship between supply heat sources and demand heat sources in chemical process systems. In solving such problems, the following difficulties appear: calculation of maximum quantity of generated electric power, determination of a suitable working fluid and its temperatures in the Rankine cycle, and so on. The proposed method can solve them using the temperature-enthalpy diagram and, furthermore, has the advantage of being able to design a final heat exchanger network with heat exchangers in a power plant by means of a synthesis method using the same diagram.     

Full-energy-chain analysis of greenhouse gas emissions for solar thermal electric power generation systems

Renewable energy generation of electricity is advocated as a means of reducing carbon dioxide emissions associated with the generation from fossil fuels. Whilst it is true that renewable sources do not generate significant carbon dioxide whilst producing electricity, as with fossil-fuelled plants they do embody significant emissions in their materials of construction. The “full-chain” environmental impacts of wind, hydro, solar-thermal and photovoltaic conversion are quite different and the likely trend in future reduction of embodied energy of next generation systems reflects the relative maturity of each technology. There has been much recent development of solar thermal electricity generation options for which there is a wide divergence in embodied CO₂ emissions.     

Feasibility-based inexact fuzzy programming for electric power generation systems planning under dual uncertainties

In this study, a feasibility based inexact fuzzy programming approach (FBIFP) was developed and applied to the planning of a regional electric power generation system (REPGS). As an extension of existing interval linear programming and fuzzy linear programming, FBIFP could tackle uncertainties expressed as intervals, fuzzy sets as well as their combination in both of the objective function and constraints. Through introducing the index of feasibility degree, FBIFP could be used to facilitate the efficient reflection of constraint violation, and thus allow decision makers to have a complete view of the relationships between uncertain inputs and the related solutions. A hypothetic regional electric power generation system was provided for demonstrating applicability of the developed model. Useful solutions for the planning of REPGS were generated. Interval solutions under different feasibility degrees were obtained. They could be used for helping decision makers identify desired alternatives under various reliability risks of the system. The solutions could also help identify optimal patterns for energy resources allocation, electricity generation and facility capacity expansion with a minimized system cost. Tradeoffs between system costs and system security could be successfully addressed through the analysis of the feasibility degrees of constraints, i.e., a higher feasibility degree would correspond to a higher system cost, while a lower system cost would run into a higher risk of potential instability of the study system.     

国内风力发电的现状和前景

分析了我国的风能资源和风力发电的现状，探讨了在风力发电时要注意的几个问题，并对我国风力发电的发展前景提出了看法。     

Use of R-114 as the working fluid in a flat-plate collector system for electric power generation

The use of flat-plate solar collectors for the generation of electric power is attracting the attention of engineers and scientists for its simplicity in construction and operation. The efficiency of collection is low due to the low operating temperatures of the flat-plate collectors. In the low temperature range applicable to flat-plate collectors, refrigerants can be used as working fluid. The cost of construction can be reduced by the suitable selection of collector and refrigerants. It has been shown that R-114 has suitable characteristics for use as a Rankine cycle working fluid. By using an aluminium tube-plate type collector with 0·005 m tube diameter, 10 risers per metre width of collector, it becomes light and cheap. When the emissivity of the collector is 0·1 and a single cover is used, the maximum efficiency condition is attained. Limited to a pressure drop of 2·5 bar in the collector, 16 collectors can be used in series and the overall efficiency can be as high as 7·8% under 1000 W/m² insolation conditions and for an outlet temperature of 380 K. Under these conditions 5600 collectors of 1·5 m × 1·5 m size will be required to produce 1000 kW of electricity.