Isotopic composition (C & N) of the suspended particles and N uptake by phytoplankton in a shallow tropical coastal lagoon

The spatial distribution of the C/N ratios and variations in δ¹³C and δ¹⁵N of suspended particulate matter were used to characterise their source in Asia’s largest brackish water lagoon, Chilika, India. In addition, the significance of re-mineralised nutrients in the primary productivity of the shallow lagoon was also determined through quantification of the subsurface nitrogen uptake conditions at two relatively stable locations in the lagoon. The results indicated that the influence of terrestrial organic matter was the maximum in the northern sector and was relatively limited at the central and southern part of the lagoon. In situ ¹⁵N uptake experiments (daytime) under biogeochemically stable conditions revealed that the N uptake by phytoplankton ranged between 0.24 and 1.01?mM?m^?3?h^?1 during pre-monsoon and post-monsoon seasons. New production and regenerated production in the shallow lagoon was also estimated by calculating f-ratios (ratio of nitrate assimilation by phytoplankton to total nitrogenous nutrient assimilation, have been estimated), which varied from 0.52 in the post-monsoon to 0.38 in the pre-monsoon. Lowering of the f-ratio from post- to pre-monsoon indicated a dominance of mineralisation over the new production.     

电网发展、清洁电源接入与地区能源效率

鉴于我国已经建成全球规模最大的超高压和特高压电网,彻底弥补了电力跨区配置的电网基础设施短板,并且为清洁电源并入电网和跨区消纳提供了完善的基础设施,不仅克服我国电力负荷中心和能源基地的区域布局不协调,而且有益于缓解日益严峻的能源利用率低下和环境污染问题。本文利用1991—2012年全国29个省市面板数据实证研究了清洁电源并网对地区全要素能源效率的影响。为保证实证结果稳健性分别在线性和非线性实证框架下采用系统广义矩估计(SYS-GMM)和面板平滑转换模型(PSTR)两种方法估计了清洁电源接入高压、超高压和特高压电网的地区全要素能源效率异质性效应。实证结果显示:(1)我国电网基础设施对地区全要素能源效率具有明显的增进效应,特别是超高压电网在促进全要素能源效率提升上表现的最为突出,在特高压骨干网架尚未形成的情况下起到了支柱性作用。(2)高压、超高压、特高压与清洁电源交互项的估计系数始终位于负数区间,反映清洁电源并网的能源效率绩效并不明显,受限于并网规模和机制缺陷,还没有发挥出全要素能源效率提升作用。(3)随着人均GDP的不断提高,各等级电网对地区能源效率的益处越来越明显,并且存在着门槛效应。(4)特高压电网对地区能源效率的积极作用主要表现在东部沿海高收入省份,这些省份作为电力消费负荷中心,大规模接入清洁电源对能源效率改善裨益明显。接下来,需要根据地区的能源禀赋结构选择清洁电源的并网模式,完善的电网基础设施、合理的电源结构还需要配置以高效的清洁电源并网机制才能不断增进地区全要素能源效率。     

Offshore wind power potential of the Black Sea region in Turkey

Majority of the studies on offshore wind power potential assessment is limited to the examination of the wind speed only. This study examines the offshore wind power potential of the Black Sea coastal region in Turkey based on location selection criteria including territorial waters, military areas, civil aviation, shipping routes, pipelines and underground cables, social, and environmental concerns. Wind Atlas Analysis and Application Program (WAsP) is used to do the statistical analysis of wind speed and wind direction data for 20 locations in the Black Sea coastal region. WAsP results are then elaborated based on the location selection criteria for better assessment of offshore wind power utilization. The study reveals that there are limited numbers of locations for offshore wind power generation in the Black Sea region in spite of its long coastline. Moreover, there is a high need for a zoning change for Amasra shores in order to utilize high offshore wind power potential of Amasra. Our finding suggests that location selection criteria other than wind speed should definitely be considered for better assessment of the wind power potential of a region.     

Microbial fuel cells: Advances in electrode modifications for improvement of system performance

There is an increasing trend to conduct the researches related to Microbial Fuel Cells (MFCs) in the recent years. Limited power output has been the major obstacle for the practical application and upscaling of MFCs. Attempts have been made on electrode modifications such as anode treatments, cathode modifications with catalysts and bio cathodes developments to produce varying degrees of improved output current depending upon the types of modifications. Power density and Coulombic efficiency have been considered as the important parameters to analyze the system performances. This paper overviews on the advances made in MFCs’ researches focusing on different types of electrodes modifications along with the involved methodology. Furthermore, the system performances of different modified MFCs are compared in terms of the power density and the Coulombic efficiency.     

Green energy generation by pressure retarded osmosis: State of the art and technical advancement—review

Pressure-retarded osmosis (PRO) is a method for converting salinity gradients to power by allowing water to flow through a semi-permeable membrane against an applied hydraulic pressure. PRO already has a long history, starting from the middle of the last century, and has rapidly improved in recent years. In this paper, we present a historical development of PRO since its inception: the development of this renewable energy process has gone through several stages, depending on technological developments, worldwide energy demands, and environmental concerns. The technological progress of the process is also studied, as well as its cost viability and environmental impact. Finally, some ideas to further develop the PRO process and mitigate its detrimental effects are discussed.     

A case study of an isolated wind powered electricity system meeting 100% of local demand

Using meteorological and electricity demand data for a 4-year period, electricity demand in Shetland was modeled to provide an estimate of the demand over a 30-year period from 1 January 1981. That modeled demand was then compared to estimated wind power output over the same period using the WAsP model. The wind farm output was estimated for a range of sizes of wind farm up to the consented 370 MW Viking Wind Farm in Shetland. Some wind power was available for 94% of the time and the 370 MW wind farm would meet 100% of demand for nearly 80% of the time. The statistics of single and accumulated deficits were calculated for a range of wind farms and estimates of the amount of additional generation capacity and additional power requirements were assessed. The study suggests that with storage, wind power in Shetland could meet all electricity demand in Shetland at around £130 to £150/MWh (excluding subsidy) and with a grid connection allowing the sale of excess power, those costs could be reduced.     

电厂建设运行中的水土流失预测与水土保持设计

在燃煤电厂建设运行的同时,将引起一系列的水土流失问题.以四川国电金堂电厂二期扩建工程为例,简要说明项目区水土流失预测的内容和方法,并在其基础上对可能产生的水土流失和危害进行了分析,同时介绍了建设期和运行期采取的综合防治措施,为类似工程的水土保持提供借鉴.     

利用卫星遥感评估广西壮族自治区SO_2减排成效

基于2005—2012年OMI卫星遥感PBL SO2柱浓度数据分析了广西壮族自治区SO2污染的时空格局和变化特征,并结合燃煤火电厂SO2排放模型估算与工业经济增长数据,在时间、空间尺度上分析了自治区内不同区域的SO2污染对火电厂烟气脱硫政策的响应以及所呈现出的减排成效。结果表明,广西因火电厂脱硫政策驱动的SO2污染改善具有显著的空间异质性,自治区内高污染区的SO2浓度在2011—2012年出现了显著下降,而低污染区的SO2浓度则在8年中持续增长;排放模型估算结果显示,烟气脱硫驱动的火电厂SO2减排贡献将在2008年后持续下降,而遥感观测结果显示,广西全区SO2半年浓度均值总体呈现波动上升趋势,2005—2012年浓度增加了8.6%、年均增长约0.9%;综合工业经济增长数据发现,近年来其他工业源的增量排放已给广西SO2减排带了新挑战,而这一变化仍未得到相关决策部门关注,存在明显缺陷的SO2统计排放量数据尚未得到修正。针对上述污染变化新特征,政府相关部门应引起足够重视,尽快更新完善污染源信息并启动针对其他污染源的限排措施,以确保环境持续改善。     

1000 MW燃煤机组电除尘深度节能技术研究及应用

电除尘设备在减少工业粉尘排放量、降低大气环境污染、保护生态环境等方面有着重要的作用,随着我国对节能减排工作的重视及环保要求的提高,保证其安全、稳定、经济、节能运行成为火电厂环保工作重点。对北仓电厂三期2×1000 MW机组电除尘电场供电方式优化、电除尘振打方式优化、电除尘闭环控制技术、电除尘高频电源技术、电除尘灰斗、瓷套蒸汽加热技术组合集成应用进行了研究,在确保除尘效率达到要求的情况下,降低运行电耗。相关的电除尘深度节能技术成果在国内同类型设备中具有一定的借鉴意义。     

电网规划环境影响评价的难点及对策建议

我国电网规划环境影响评价工作正处在起步阶段,缺乏成熟的理论方法和指标体系。结合常州市“十二五”电网发展规划环境影响评价工作,探讨了电网规划环评中存在的难点和问题并提出了相应的对策建议。