Power supply for pumping systems in northern Chile: Photovoltaics as alternative to grid extension and diesel engines

This paper examines and compares the cost-effectiveness to energize pumping systems in remote areas on northern Chile by means of photovoltaic systems, diesel engines and grid extension. Variables such as the distance to the power grid, the voltage grid, the prices of electricity and fuel, and the required investments, are taken into account. The comparison is made for wide range of variable values, distances and pumping requirements. The results obtained are useful for choosing the best alternative for the power supply of pumping systems in wells in Northern Chile.     

Parametric study of cascade latent heat thermal energy storage (CLHTES) system in Concentrated Solar Power (CSP) plants

Recently, Concentrated Solar Power (CSP) is attracting numerous research attentions, and thermal energy storage (TES) system filled with energy storage media is a critical component in all CSP plants. To realize a high energy storage efficiency ($\xi$) and exergy efficiency ($\eta$), a comprehensive study to the cascade latent heat thermal energy storage (CLHTES) system is necessary from the perspective of heat transfer. In this study, a dimensionless parametric study was presented using an enthalpy-based 1D transient model for energy storage/extraction in CLHTES system. A dimensionless parameter space (${\tau }_r,H_{CR},St{f}^{\text{*}}$) was constructed by considering $\xi$ and $\eta$ as the objective functions to explore the effects from dimensionless material properties (such as latent heat, specific heat at solid and liquid phases) and dimensionless operational parameters (such as charging/discharging time period, TES tank height and diameter). It is recommended that when $H_{CR}$<0.5 and ${\Pi }_c/{\Pi }_d$<1.0, the system performance is very sensitive to $H_{CR}$ and ${\Pi }_c/{\Pi }_d$, furthermore for the same TES tank volume (H/D = D/H = 1.0), the sensitivity by varying its diameter alone is double than that from changing its height. The novelty of this study is to provide the design criteria for the CLHTES system, so that it can easily be designed and its efficiencies can be competitive to sensible heat thermal energy storage (SHTES) system. The results from this parametric study and sensitivity analysis are expected to benefit the solar thermal research and industry community to design the CLHTES system.     

Performance model to assist solar thermal power plant siting in northern Chile based on backup fuel consumption

In response to environmental awareness, Chile introduced sustainability goals in its electricity law. Power producers must deliver 5% from renewable sources by 2010 and 10% by 2024. The Chilean desert has a large available surface with one of the highest radiation levels and clearest skies in the World. These factors imply that solar power is an option for this task. However, a commercial plant requires a fossil fuel system to backup the sunlight intermittency. The authors developed a thermodynamical model to estimate the backup fraction needed in a 100 MW hybrid -solar-fossil- parabolic trough power plant. This paper presents the model aiming to predicting the performance and exploring its usefulness in assisting site selection among four locations. Since solar radiation data are only available in a monthly average, we introduced two approaches to feed the model. One data set provided an average month with identical days throughout and the other one considered an artificial month of different daylight profiles on an hourly basis for the same monthly average. We recommend a best plant location based on minimum fossil fuel backup, contributing to optimal siting from the energy perspective. Utilities will refine their policy goals more closely when a precise solar energy data set becomes available.     

The cost of integration of parabolic trough CSP plants in isolated Mediterranean power systems

In this work, a technical and economic analysis concerning the integration of parabolic trough concentrated solar power (CSP) technologies, with or without thermal storage capability, in an existing typical small isolated Mediterranean power generation system, in the absence of a feed-in tariff scheme, is carried out. In addition to the business as usual (BAU) scenario, five more scenarios are examined in the analysis in order to assess the electricity unit cost with the penetration of parabolic trough CSP plants of 50 MWe or 100 MWe, with or without thermal storage capability. Based on the input data and assumptions made, the simulations indicated that the scenario with the utilization of a single parabolic trough CSP plant (either 50 MWe or 100 MWe and with or without thermal storage capability) in combination with BAU will effect an insignificant change in the electricity unit cost of the generation system compared to the BAU scenario. In addition, a sensitivity analysis on natural gas price, showed that increasing fuel prices and the existence of thermal storage capability in the CSP plant make this scenario marginally more economically attractive compared to the BAU scenario.     

Comparative study of single and multi-layered packed-bed thermal energy storage systems for CSP plants

The Multi-layered Thermal Energy Storage (TES) tank consists of three regions–top and bottom part is packed with suitable Phase Change Materials (PCM) and low-cost pebbles are placed in the middle region, whereas entire tank portion is filled by solid fillers in Single-layered tank system. For a storage tank operating between 563 and 663 K with bed dimensions of 12 and 14.38 m using Solar salt as Heat Transfer Fluid (HTF), it is observed that the duration of discharge for multi-layered tank is 5.32 h whereas it is 4.19 h for single-layered tank with a Reynolds number of 10. The effect of intermediate melting temperature range of PCMs are also analyzed by taking PCMs with sharp as well as intermediate melting ranges. Further, comparison of single and multi-layered systems is carried out by analyzing the temperature profiles and width of both PCM layers. The width of top and bottom PCM layers of tank is varied from 0 to 30% to analyze its effect on the discharging duration. It is observed that multi-layered system provides extra discharge of 1 h with introduction of PCM at top and bottom with a width of 10%. Discharge duration increases with increase in PCM width whereas the percentage increase in duration of discharge with increase in PCM width is comparatively less. It is also seen that PCMs with sharp melting point performs better compared to one having intermediate range of melting temperatures. Multi-layered configuration concept offers best possibilities as integration to CSP plants with desired efficiency.     

聚光太阳能发电技术应用与前景

分析了聚光太阳能发电三大技术（线性聚光系统、碟/引擎系统、电力塔系统）以及热能储存系统,阐述了其结构、工作原理与研究方向,比较了这三大技术之间的经济技术性能,介绍了适合我国太阳能辐射量大的边远地区碟/引擎系统的应用,展示了太阳能热发电技术的应用前景及对节能减排的贡献。     

Entropy generation and Carnot efficiency comparisons of high temperature heat transfer fluid candidates for CSP plants

Heat transfer fluid is a critical component in a concentrating solar power plant. A large quantity of heat transfer fluid is required to transfer heat between the solar collector and the power block, thus it is crucial to select the most appropriate heat transfer fluid in order to maximize the system performance. The present study compared the performances of five molten-salt eutectic mixtures in regarding with the entropy generation rate and the Carnot efficiency of using them as heat transfer fluids. All the five molten-salt eutectic mixtures have thermal stability temperatures above 600 °C. Effects of the tube lengths in the steam generation heat exchanger and the receiver heat exchanger as well as the heat transfer fluid flow rate on both the entropy generation rate and the Carnot cycle efficiency were investigated. The results indicate that the carbonate salts has the worst performances compared to the other eutectic mixtures. The three chloride salts have slightly higher entropy generation rate and 5% higher Carnot efficiency than the Solar Salt. Therefore the three chloride salts are suggested to be used in advanced concentrating solar power tower plants as potential high temperature heat transfer fluids.     

Robust tuning of power system stabilisers to install in wind energy conversion systems

This paper addresses the problem of robustly tuning power system stabilisers (PSSs) in systems with large wind power integration. PSSs installed in wind energy conversion systems, namely in doubly fed induction generators, are used in this research to provide additional damping to the electromechanical modes of oscillation. A new method that aims to reduce the computational effort required to find a robust solution that is suitable for a very large set of operating conditions is also proposed.     

Impact of heat,power and hydrogen generation on optimal placement and operation of fuel cell power plants

In this paper, a stochastic model is proposed for planning the location and operation of Fuel Cell Power Plants (FCPPs) as Combined Heat, power, and Hydrogen (CHPH) units. Total cost, emissions of FCPPs and substation, and voltage deviation are the objective functions to be minimized. Location and operation of FCPPs as CHPH are considered in this paper while their investment cost is not taken into account. In the proposed model, indeterminacy refers to electrical and thermal loads forecasting, pressure of oxygen and hydrogen, and the nominal temperature of FCPPs. In this method, scenarios are produced using roulette wheel mechanism and probability distribution function of input random variables. Using this method, the probabilistic problem is considered to be distributed as some scenarios and consequently probabilistic problem is considered as combination of some deterministic problems. Considering the nature of objective functions, the problem of locating and operating FCPPs as CHPH is considered as a mixed integer nonlinear problem. A Self Adaptive Charged System Search (SACSS) algorithm is employed for determining the best Pareto optimal set. Furthermore, a set of non-dominated solutions is saved in repository during simulation procedure. A 69-bus distributed system is used for verifying the beneficiary proposed method.     

Mineralogy,geochemistry and leachability of ashes produced after lignite combustion in Amyntaio Power Station,northern Greece

The Kozani–Ptolemais–Amyntaio basin constitutes the principal coal field of Greece. Approximately 50% of the total power of Greece is generated by five power stations operating in the area. Pulverized lignite, a bottom ash, and a fly ash sample from the power plant of Amyntaio were subjected to a leaching procedure. The relative mass leached (RML) of three potentially toxic trace elements (Cu, Cr, Ni) was determined by use of AAS. Results indicate that the determined elements are more readily available in fly ash than in bottom ash or pulverized lignite. Mineralogical examination of the samples has revealed that calcite, gypsum, quartz, and feldspar are the constituents of lignite; quartz and calcite are found in fly ash particles; while gypsum, quartz, and calcite are found in bottom ash.     

苏州市吴中区地方电厂节能降耗成效显著

为确保实现2010年苏州市单位国内生产总值能耗比“十五“期末下降20%左右,主要污染物排放总量减少10%的约束性指标的实现,苏州市吴中区发展和改革局今年对吴中区各非省调度地方电厂的节能降耗情况进行了调研,了解节能降耗工作开展状况.……     

Potential and impacts of Concentrated Solar Power (CSP) integration in the Brazilian electric power system

This study analyses the Concentrated Solar Power (CSP) potential in Brazil and evaluates the impact caused by a large-scale integration of this alternative into the Brazilian electricity system in the long term (horizon 2040). Four types of CSP plants with parabolic troughs (simple plants, plants with hybridization and plants with thermal energy storage) were simulated at two sites: Bom Jesus da Lapa and Campo Grande. Then, the main parameters obtained for each plant were expanded to other suitable Brazilian sites, as inputs in an optimization model for the expansion of the country's electric power grid. Findings indicate that the least-cost expansion of the Brazilian electricity system should be based on hydroelectric and thermoelectric plants fueled by natural gas and sugarcane bagasse. Hence, in the base scenario CSP plants would not be chosen. However, in an alternative scenario, specific auctions for CSP can be adopted. In this case, the first solar plants would be introduced in 2020 in place of natural gas-fueled thermoelectric plants, and from 2030 on, hydroelectric plants would cease to be installed. This alternative scenario would be about 144 billion dollars dearer than the base.     

GIS assessment of large CSP plant in Duqum,Oman

This paper discusses solar power prospects in Wilayat Duqum in Oman. First, the geographic and topographic information about the selected region is presented. The methodology of producing solar radiation map for Duqum using GIS tools is then presented. The results obtained show very high potential of solar radiation over Wilayat Duqum during the whole year. A slope analysis has allowed calculating the yearly electricity generation potential for different concentrated solar power (CSP) technologies such as the parabolic trough, parabolic dish, tower, and concentrated PV. Based on the development plan of the Duqum region, and the topologies of the land areas in the region, it is suggested that, for the CSP technologies requiring large amount of water for washing the mirrors, the selected area is a flat land (slope < 1%) located proximity to the sea (～2 km) inside a total industrial area of around 50 km², hence, allowing easy future expansion of the plant. It was proposed to start with a 100 MW power plant which is expected to consume about 2.4 km² of flat land for the parabolic trough CSP technology. The total calculated potential of yearly electricity generation would be about 2.3 TWh. If half of the selected land (0.5 × 50 km²) is reserved for future expansion of the plant, the total future capacity can attain 1 GW of electric power. The selected area can also accommodate in the future different types of CSP technologies as they mature with time.     

建设抽水蓄能电站必要性的思考

抽水蓄能电站具有填谷调峰的优良特性.详述了调频、调相、负荷调整、旋转备用、提高电网可靠性的辅助功能以及世界和中国抽水蓄能电站的发展情况.提出我国在火电比重大和建设核电站的电网及"西电动送"受端电网,优先发展抽水蓄能电站,在水电比重较大,但调节性能差的电网,适当配置抽水蓄能电站.抽水蓄能电站一般应修建在负荷中心附近,且有天然湖泊或已建水库处.     

Climatology of surface ultraviolet-radiation in Valparaiso,Chile

Despite the lack of long-term records, it is possible to describe many of the short term characteristics, dependencies and climatology of surface UV irradiance. This paper describes the climatology of on ground UV irradiance at Valparaiso (33.05°S, 71.63°W, sea level), Chile. The dependence of UV-B irradiance on ozone and on other climate variables is discussed with reference to our observations conducted during the last four years. Special attention was paid to detect “ozone events” by surface UV irradiance measurements. By analyzing time series of the UV-B/UV-A ratio, we suppressed the cloud variability effect and detected events that implied ozone column changes of about 15%. According to our measurements, during the last four years, the ozone column over Valparaiso was not affected negatively by the Antarctic ozone hole phenomenon.     

建设抽水蓄能电站必要性的思考

抽水蓄能电站具有填谷调峰的优良特性。详述了调频、调相、负荷调整、旋转备用、提高电网可靠性的辅助功能以及世界和中国抽水蓄能电站的发展情况。提出我国在火电比重大和建设核电站的电网及"西电动送"受端电网,优先发展抽水蓄能电站,在水电比重较大,但调节性能差的电网,适当配置抽水蓄能电站。抽水蓄能电站一般应修建在负荷中心附近,且有天然湖泊或已建水库处。     

建设抽水蓄能电站必要性的思考

抽水蓄能电站具有填谷调峰的优良特性.详述了调频、调相、负荷调整、旋转备用、提高电网可靠性的辅助功能以及世界和中国抽水蓄能电站的发展情况.提出我国在火电比重大和建设核电站的电网及"西电动送"受端电网,优先发展抽水蓄能电站,在水电比重较大,但调节性能差的电网,适当配置抽水蓄能电站.抽水蓄能电站一般应修建在负荷中心附近,且有天然湖泊或已建水库处.     

Technological,economic and sustainability evaluation of power plants using the Analytic Hierarchy Process

Complexity of power plant evaluation is steadily rising, as more criteria are involved in the overall assessment while evaluation data change rapidly. Apart from evaluating several aspects of power plants separately, a multicriteria analysis based on hierarchically structured criteria is necessary, so as to address the overall assessment of power plants according to the technological, economic and sustainability aspects. For this reason, in this paper, ten types of power plant are evaluated using nine end node criteria properly structured under the Analytical Hierarchy Process. Moreover, pairwise comparisons allow for accurate subjective criteria weighting.