Thermal Power Plants

This article presents results from the first statistically significant study of cost escalation in transportation infrastructure projects. Based on a sample of 258 transportation infrastructure projects worth US$90 billion and representing different project types, geographical regions, and historical periods, it is found with overwhelming statistical significance that the cost estimates used to decide whether such projects should be built are highly and systematically misleading. Underestimation cannot be explained by error and is best explained by strategic misrepresentation, that is, lying. The policy implications are clear: legislators, administrators, investors, media representatives, and members of the public who value honest numbers should not trust cost estimates and cost-benefit analyses produced by project promoters and their analysts.

This article presents results from the first statistically significant study of traffic forecasts in transportation infrastructure projects. The sample used is the largest of its kind, covering 210 projects in 14 nations worth U.S.$59 billion. The study shows with very high statistical significance that forecasters generally do a poor job of estimating the demand for transportation infrastructure projects. For 9 out of 10 rail projects, passenger forecasts are overestimated; the average overestimation is 106%. For half of all road projects, the difference between actual and forecasted traffic is more than ±20%. The result is substantial financial risks, which are typically ignored or downplayed by planners and decision makers to the detriment of social and economic welfare. Our data also show that forecasts have not become more accurate over the 30-year period studied, despite claims to the contrary by forecasters. The causes of inaccuracy in forecasts are different for rail and road projects, with political causes playing a larger role for rail than for road. The cure is transparency, accountability, and new forecasting methods. The challenge is to change the governance structures for forecasting and project development. Our article shows how planners may help achieve this.

The article first describes characteristics of major infrastructure projects. Second, it documents a much neglected topic in economics: that ex ante estimates of costs and benefits are often very different from actual ex post costs and benefits. For large infrastructure projects the consequences are cost overruns, benefit shortfalls, and the systematic underestimation of risks. Third, implications for cost–benefit analysis are described, including that such analysis is not to be trusted for major infrastructure projects. Fourth, the article uncovers the causes of this state of affairs in terms of perverse incentives that encourage promoters to underestimate costs and overestimate benefits in the business cases for their projects. But the projects that are made to look best on paper are the projects that amass the highest cost overruns and benefit shortfalls in reality. The article depicts this situation as ‘survival of the unfittest’. Fifth, the article sets out to explain how the problem may be solved, with a view to arriving at more efficient and more democratic projects, and avoiding the scandals that often accompany major infrastructure investments. Finally, the article identifies current trends in major infrastructure development. It is argued that a rapid increase in stimulus spending, combined with more investments in emerging economies, combined with more spending on information technology is catapulting infrastructure investment from the frying pan into the fire.

This paper focuses on problems and their causes and cures in policy and planning for large-infrastructure projects. First, it identifies as the main problem in major infrastructure developments pervasive misinformation about the costs, benefits, and risks involved. A consequence of misinformation is cost overruns, benefit shortfalls, and waste. Second, it explores the causes of misinformation and finds that political-economic explanations best account for the available evidence: planners and promoters deliberately misrepresent costs, benefits, and risks in order to increase the likelihood that it is their projects, and not those of their competition, that gain approval and funding. This results in the ‘survival of the unfittest’, in which often it is not the best projects that are built, but the most misrepresented ones. Finally, it presents measures for reforming policy and planning for large-infrastructure projects with a focus on better planning methods and changed governance structures, the latter being more important.

A major source of risk in project management is inaccurate forecasts of project costs, demand, and other impacts. The paper presents a promising new approach to mitigating such risk, based on theories of decision making under uncertainty which won the 2002 Nobel prize in economics. First, the paper documents inaccuracy and risk in project management. Second, it explains inaccuracy in terms of optimism bias and strategic misrepresentation. Third, the theoretical basis is presented for a promising new method called "reference class forecasting," which achieves accuracy by basing forecasts on actual performance in a reference class of comparable projects and thereby bypassing both optimism bias and strategic misrepresentation. Fourth, the paper presents the first instance of practical reference class forecasting, which concerns cost forecasts for large transportation infrastructure projects. Finally, potentials for and barriers to reference class forecasting are assessed.

"Over budget, over time, over and over again" appears to be an appropriate slogan for large, complex infrastructure projects. This article explains why cost, benefits, and time forecasts for such projects are systematically over-optimistic in the planning phase. The underlying reasons for forecasting errors are grouped into three categories: delusions or honest mistakes; deceptions or strategic manipulation of information or processes; or bad luck. Delusion and deception have each been addressed in the management literature before, but here they are jointly considered for the first time. They are specifically applied to infrastructure problems in a manner that allows both academics and practitioners to understand and implement the suggested corrective procedures. The article provides a framework for analyzing the relative explanatory power of delusion and deception. It also suggests a simplified framework for analyzing the complex principal-agent relationships that are involved in the approval and construction of large infrastructure projects, which can be used to improve forecasts. Finally, the article illustrates reference class forecasting, an outside view de-biasing technique that has proven successful in overcoming both delusion and deception in private and public investment decisions.

This paper presents a mixed-integer linear programming (MILP) super-structure model for the optimal design of distributed energy generation systems that satisfy the heating and power demand at the level of a small neighborhood. The objective is the optimal selection of the system components among several candidate technologies (micro combined heat and power units, photovoltaic arrays, boilers, central power grid), including the optimal design of a heating pipeline network, that allows heat exchange among the different nodes. The objective function to be minimised contains the annualised overall investment cost and the annual operating cost of the system. We show that besides the usual energy balance and unit operations constraints, additional equations must be included in the model to guarantee correctness of the produced heating pipeline designs. A special instance of the problem where a single centralised combined heat and power unit is installed in the neighborhood is also considered. The efficiency of the proposed model is evaluated through illustrating examples.

The Supplementary Green Book Guidance on Optimism Bias (HM Treasury 2003) with reference to the Review of Large Public Procurement in the UK (Mott MacDonald 2002) notes that there is a demonstrated, systematic, tendency for project appraisers to be overly optimistic and that to redress this tendency appraisers should make explicit, empirically based adjustments to the estimates of a project’s costs, benefits, and duration. HM Treasury recommends that these adjustments be based on data from past projects or similar projects elsewhere, and adjusted for the unique characteristics of the project in hand. In the absence of a more specific evidence base, HM Treasury has encouraged departments to collect data to inform future estimates of optimism, and in the meantime use the best available data. In response to this, the Department for Transport (henceforth DfT), has contracted Bent Flyvbjerg in association with COWI to undertake the consultancy assignment "Procedures for dealing with Optimism Bias in Transport Planning". The present Guidance Document is the result of this assignment.

This work presents an integrated approach for the design and evaluation of distributed energy resources (DER) systems, based on a detailed Mixed Integer Linear Programming (MILP) model. The mathematical model takes into account energy requirements of the site, local climate data, utility tariff structure, characteristics of the candidate DER technologies (technical and financial) as well as geographical aspects. The model also considers the integration of a heating piping network. The optimal integrated DER system is obtained by minimising an objective function that contains investment, operational, maintenance and environmental costs.

2008. 352 pp. r150.00 (hardcover). This volume is intended to explain why major investment projects (the so-called mega-projects) often are not completed on time and cost more than originally budgeted. Drawing from experiences of European and North American countries, the book also suggests ways to avoid such failures. Although the topic is rather specific, the book is worth reading for both experts and nonexperts as infrastructure development continues to be a major key to economic expansion across the globe.g row_486 380.. 408 For those who only have a vague idea of what a mega-project is, the book begins by introducing the topic and reviewing the most important recent literature. The first part of the volume, then, provides numerous insights on the complexity of mega-projects, starting from the large number of reasons why mega-projects might fail. For example, the project might be "underdesigned," thus less costly but less robust to unforeseen developments, or it might be "overdesigned," when a large number of weaknesses and possible problems are considered in advance, and solutions are evaluated before the problem actually occurs. Overdesigned projects are more robust, less likely to fail, but are much more costly. The project might involve the use of innovative technologies that have never been applied to a similar context, and that involve more uncertain implementation costs and results. Most projects have an impact on the environment and might face opposition for example from environmentalist groups. If representative of these groups have not been directly involved in the design of the project, they might try to stop it, thus causing delays and increasing costs. Finally, because of incorrect predictions of 380 GROWTH AND CHANGE, JUNE 2009

Risk, including economic risk, is increasingly a concern for public policy and management. The possibility of dealing effectively with risk is hampered, however, by lack of a sound empirical basis for risk assessment and management. This article demonstrates the general point for cost and demand risks in urban rail projects. The article presents empirical evidence that allow valid economic risk assessment and management of urban rail projects, including benchmarking of individual or groups of projects. Benchmarking of the Copenhagen Metro is presented as a case in point. The approach developed is proposed as a model for other types of policies and projects in order to improve economic and financial risk assessment and management in policy and planning.

This paper explores how theories of the planning fallacy and the outside view may be used to conduct quality control and due diligence in project management. First, a much-neglected issue in project management is identified, namely that the front-end estimates of costs and benefits – used in the business cases, cost-benefit analyses, and social and environmental impact assessments that typically support decisions on projects – are typically significantly different from actual ex post costs and benefits, and are therefore poor predictors of the actual value and viability of projects. Second, it is discussed how Kahneman and Tversky’s theories of the planning fallacy and the outside view may help explain and remedy this situation through quality control of decisions. Third, it is described what quality control and due diligence are in the context of project management, and an eight-step procedure is outlined for due diligence based on the outside view. Fourth, the procedure is tested on a real-life, multibillion-dollar project, organized as a public-private partnership. Finally, Akerlof and Shiller’s recent discussion in economics of “firing the forecaster” is discussed together with its relevance to project management. In sum, the paper demonstrates the need, the theoretical basis, a practical methodology, and a real-life example for how to de-bias project management using quality control and due diligence based on the outside view.

In 2014, China introduced an ultra-low emissions (ULE) standards policy for renovating coal-fired power-generating units to limit SO2, NOx and particulate matter (PM) emissions to 35, 50 and 10 mg m−3, respectively. The ULE standard policy had ambitious levels (surpassing those of all other countries) and implementation timeline. We estimate emission reductions associated with the ULE policy by constructing a nationwide, unit-level, hourly-frequency emissions dataset using data from a continuous emissions monitoring systems network covering 96–98% of Chinese thermal power capacity during 2014–2017. We find that between 2014 and 2017 China’s annual power emissions of SO2, NOx and PM dropped by 65%, 60% and 72%, respectively. Our estimated emissions using actual monitoring data are 18–92% below other recent estimates. We detail the technologies used to meet the ULE standards and the determinants of compliance, underscoring the importance of ex post evaluation and providing insights for other countries wishing to reduce their power emissions.

Do different types of megaprojects have different cost overruns? This apparently simple question is at the heart of research at the University of Oxford aimed at understanding the characteristics of megaprojects, particularly in terms of how they are established, run and concluded. In this study, we set out to investigate cost overruns in the Olympic Games. To do so, we examined the costs of the Games over half a century, including both summer and winter Olympics. We looked at the evolution of final reported costs and compared these to the costs established in the Games bids, submitted to the International Olympic Committee (IOC) up to seven years before the Games occurred. In so doing we established the largest dataset of its kind, and documented for the first time in a consistent fashion the costs and cost overruns for the Olympic Games, from 1960 to 2012. We discovered that the Games stand out in two distinct ways compared to other megaprojects: (1) The Games overrun with 100 per cent consistency. No other type of megaproject is this consistent regarding cost overrun. Other project types are typically on budget from time to time, but not the Olympics. (2) With an average cost overrun in real terms of 179 per cent – and 324 per cent in nominal terms – overruns in the Games have historically been significantly larger than for other types of megaprojects, including infrastructure, construction, ICT, and dams. The data thus show that for a city and nation to decide to host the Olympic Games is to take on one of the most financially risky type of megaproject that exists, something that many cities and nations have learned to their peril. For the London 2012 Games, we find that: (1) With sports-related real costs currently estimated at USD14.8 billion, London is on track to become the most costly Olympics ever. (2) With a projected cost overrun of 101 per cent in real terms, overrun for London is below the historical average for the Games, but not significantly so. (3) The London cost overrun is, however, significantly higher than overruns for recent Games since 1999. London therefore is reversing a positive trend of falling cost overruns for the Games.

Large-scale and high throughput approaches increasingly play an essential role in the study of biological systems, which are per se highly complex. Therefore, they need to be examined by these extensive methods to receive information about the large genomic and proteomic networks. In plant biology, this purpose has a strong support through the accessability of the complete genome sequence of the model plant Arabidopsis thaliana. This brief review intends to focus on the basics and the state-of-the-art of these high-throughput technologies and their application to plant proteomics. It describes protein microarrays, the use of antibodies, 2-DE and MS methods and the yeast two hybrid system, which are emerging as the major technologies for plant proteomics.

Humanity's unceasing ingenuity is generating vast economic gain for billions of people with goods unavailable to even kings and queens throughout most of history. Unfortunately, this economic growth has triggered unprecedented security challenges of global and historical magnitude: more absolute poor than any time in human history, the sixth largest extinction spasm of life on earth, climate destabilization with mega-catastrophic consequences, and multi-trillion dollar wars over access to energy. These multiple, inextricably interwoven challenges have low probability of being solved if decision makers maintain the strong propensity to think and act as if life is linear, has no carrying capacity limits, uncertainty is controllable, the future free of surprises, planning is predictable and compartmentalized into silos, and Gaussian distributions are taken as the norm while fat-tail futures are ignored. Although the future holds irreducible uncertainties, it is not fated.

Cell suspension cultures of Gymnema sylvestre treated with four different elicitors, methyl jasmonate (MJ), yeast extract, chitin and pectin were studied for the production of gymnemic acid as gymnemagenin equivalent, that was analyzed by high performance liquid chromatography (HPLC). All the four tested elicitors induced gymnemic acid production in cell suspension cultures. Highest gymnemic acid content was achieved following treatment with yeast extract (100.47 ± 0.28 mg/l), this was followed by MJ (70.43 ± 0.26 mg/l), pectin (64.19 ± 0.23 mg/l) and chitin (62.72 ± 0.13 mg/l). The addition of elicitors has shown a significant influence on cell growth that affected cell growth compared to respective controls. The highest gymnemic acid production was obtained after 20 days of elicitation in cultures treated with 0.5 g l−l yeast extract, it was 5.25-folds greater than in control. These results suggest that the addition of an elicitor to Gymnema sylvestre cell suspension cultures could stimulate and enhance gymnemic acid production. In our present study we could able to overproduce gymnemic acid up to 51.97 ± 0.26 mg l−l (dry weight basis) in yeast extract treated cell suspension cultures.

A B S T R A C T Bioenergy with Carbon Capture and Storage (BECCS) is recognised as a key technology to mitigate CO 2 emissions and achieve stringent climate targets due to its potential for negative emissions. However, the cost for its deployment is expected to be higher than for fossil-based power plants with CCS. To help in the transition to fully replace fossil fuels, co-firing of coal and biomass provide a less expensive means. Therefore, this work examines the co-firing at various levels in a pulverised supercritical power plant with post-combustion CO 2 capture, using a fully integrated model developed in Aspen Plus. Co-firing offers flexibility in terms of the biomass resources needed. This work also investigates flexibility within operation. As a result, the performance of the power plant at various part-loads (40%, 60% and 80%) is studied and compared to the baseline at 100%, using a constant fuel flowrate. It was found that the net power output and net efficiency decrease when the biomass fraction increases for constant heat input and constant fuel flow rate cases. At constant heat input, more fuel is required as the biomass fraction is increased; whilst at constant fuel input, derating occurs, e.g. 30% derating of the power output capacity at firing 100% biomass compared to 100% coal. Co-firing of coal and biomass resulted in substantial power derating at each part-load operation.

An open and indiscriminate disposal of coal fly ash causes extensive changes in physicochemical properties of soil and water. Few studies propose that coal fly ash is a potential soil ameliorant that may improve the physical, chemical, biological properties, and nutritional quality of the agricultural soil. However, several recent studies documented that incorporation of higher dosages of coal fly ash into water and soil releases toxic elements consequently creating soil and groundwater pollution leading to major health, environmental, and land use problems. To assess the environmental impact of hazardous coal fly ash on the ecological system, physicochemical and hydrogeochemical analysis of both soil and groundwater are performed. X-ray diffractograms (XRD) of soils from agricultural and landfill sites (n = 8) along with coal fly ash (n = 2) show the presence of characteristic minerals of coal fly ash and also toxic arsenic mineral phases suggesting the strong influence of hazardous coal fly ash on agricultural soil. The hydrogeochemical parameters of groundwater samples (n = 27) are analyzed which show elevated concentrations of most of the major ions corresponding to higher values than maximum permissible levels of recommended drinking water standards by World Health Organization (WHO) and Bureau of Indian Standards (BIS). The water quality indices (WQI) suggests poor to unsuitable water for drinking. Conversely, evaluation of various other hydrochemical indices calculated using elemental concentration of the groundwater samples demarcates contamination of water due to the open dumping of coal fly ash and therefore not desirable for drinking purposes.

The paper presents a theoretical analysis of advanced gas-turbine cycles. Specifically, three cycles are investigated, that is the intercooled, the reheat, and the intercooled and reheat cycles. The internal irreversibilities, which characterise the compression and expansion processes, are taken into account through the polytropic efficiencies of the compressors and turbines. New analytical formulations for the overall and intermediate pressure-ratios which maximise the net work of the three aforemen-tioned cycles are proposed along with an order relation between these optimum pressure-ratios. Moreover, the thermal efficiency of these cycles is also analysed providing, among other findings, the ranges of the intermediate pressure-ratios returning a benefit in the thermal efficiency in comparison with the simple cycle. Finally, for the sole intercooled and reheat cycle, a novel analytical expression for the maximum point of the thermal efficiency is given. It is also shown that, for the intercooled and reheat cycle, there is a unique value of the overall pressure-ratio which simultaneously maximises the net work and the thermal efficiency. To give some quantitative information, consider a maximum to minimum cycle-temperature ratio equal to 1573/300 and a com-pressor (resp. turbine) polytropic-efficiency equal to 0.8 (resp. 0.88). The net work and the thermal efficiency are maximised by a set of overall pressure-ratios obeying an order relation. The simple, the reheat, the intercooled, and the intercooled and reheat cycles reach the maximum network (resp. thermal efficiency) for increasing values of the overall pressure-ratio, that is 8.550 (resp. 18.260), 14.950 (resp. 25.039), 20.846 (resp. 39.984), and 73.109 (resp. 73.109). The reheat cycle achieves a 34.899% (resp. 6.077%) gain in the net work (resp. thermal efficiency), while the intercooled cycle returns a 31.477% (resp. 15.970%) increment. The maximum network of the intercooled and reheat cycle exactly doubles that of the simple cycle. Finally, the maximum thermal efficiency of the intercooled and reheat cycle yields a 24.966% improvement in comparison with the simple one.

This paper evaluates small hydropower (SHP) development and examines the current situation in Nigeria with respect to the established policies and Energy Power Sector Reform (EPSR) Act 2005. Hydropower sector witnessed about 360% growth between 1971 and 2005 and yet only about 5% of the vast small hydropower (SHP) potential is tapped by the few plants built between 1923 and 1964. Operating and maintenance costs are in favor of SHP development in the country, being the lowest when compared with the situation in European countries. The Nigerian Government has taken steps to diversify energy sources in order to promote renewable energy development by encouraging private investments in the energy sector through reforms, but this may not be adequate as there remain barriers against SHP development in the country. It is concluded that government must incorporate subsidies, feed-in-tariffs, and framework for Price Purchase Agreements (PPA) into the policies in order to further promote renewable energy and attract both indigenous and foreign investments for quick adoption and rapid expansion of SHP technologies.

Exergy and environmental analyses have been developed to determine the performance of the electricity generation in the Dutch mix. A comparative assessment of diverse technological routes, including fossil and renewable energy resources consumption, is carried out in terms of the exergy costs and specific CO2 emissions. Hence, an exergoeconomy methodology is used to properly allocate the renewable and non-renewable exergy costs and specific CO2 emissions among the various products of the polygeneration energy systems. By using a suitable methodology, the distribution of irreversibility throughout the different steps of the energy conversion processes of the Dutch electricity mix is characterized in the light of the Second Law of Thermodynamics. The results may help to propose performance indicators that support the Dutch government and research institutions. To identify sustainable energy planning strategies and fairly comparing electricity generation and end-use processing stages with other types of energy resources, such as fuels used in transportation, residential and industrial sectors. In brief, the weighted average of the renewable and non-renewable unit exergy costs and the specific CO2 emissions of the electricity generated in each route of the Dutch mix is calculated and compared to another electricity mix with a higher share of renewable energy resources.

Shifting to a low-carbon electricity future requires up-to-date information on the energetic, environmental and socioeconomic performance of technologies. Here, we present a novel comprehensive bottom-up process chain framework that is applied to 19 electricity generation technologies, consistently incorporating 12 life-cycle phases from extraction to decommissioning. For each life-cycle phase of each technology the following 4 key metrics were assessed: material consumption, energy return ratios, job requirements and greenhouse gas emissions. We also calculate a novel global electricity to grid average for these metrics and present a metric variability analysis by altering transport distance, load factors, efficiency, and fuel density per technology. This work quantitatively supports model-to-policy frameworks that drive technology selection and investment based on energetic-economic viability, job creation and carbon emission reduction of technologies. The results suggest energetic-economic infeasibility of electricity generation networks with substantial shares of: i) liquefied natural gas transport, ii) long distance transport based hard and brown coal and pipeline natural gas, and iii) low-load factor solar-photovoltaic, Page 2 of 37 concentrated solar power, onshore and offshore wind. Direct sector jobs can be expected to double in renewable-majority scenarios. All combustion-powered technologies without natural (biomass) or artificial carbon capture (fossil fuels) are not compatible with a low carbon electricity generation future.

Emerging economies with rapidly growing population and energy demand, own some of the most expensive power plants in the world. We hypothesized that corruption has a relationship with the capital cost of power plants in developing countries such as Bangladesh. For this study, we analyzed the capital cost of 61 operational and planned power plants in Bangladesh. Initial comparison study revealed that the mean capital cost of a power plant in Bangladesh is twice than that of the global average. Then, the statistical analysis revealed a significant correlation between corruption and the cost of power plants, indicating that higher corruption leads to greater capital cost. The high up-front cost can be a significant burden on the economy, at present and in the future, as most are financed through international loans with extended repayment terms. There is, therefore, an urgent need for the review of the procurement and due diligence process of establishing power plants, and for the implementation of a more transparent system to mitigate adverse effects of corruption on megaprojects.

Hardgrove grindability index Co-combustion Emissions profile and power plant a b s t r a c t This study aims to assess the torrefaction of biomass as alternative renewable energy fuel to coal during co-firing. It was evaluated that torrefaction improves biomass grindability to such an extent that it can be used in coal mills with coal in co-firing without capital intensive modification. Torrefaction of beech wood was performed on a batch scale reactor at three different temperatures (200, 250 and 300 C) with 30 min of residence time. The chemical structural changes in torrefied biomass were investigated with binding energies and FTIR (Fourier transform infrared) analysis. Monocombustion and co-combustion tests were performed to examine the combustion behaviour regarding flue gas emissions (CO, NOx and SO 2) at 0.5, 1.5 and 2.5 m distance from the burner opening along with fly ash analysis. The FTIR and binding energies showed that lignin hardly affected during light torrefaction while hemicellulosic material was significantly depleted. The Hardgrove grindability index (HGI) was calculated with three methods (DIN51742, IFK and ISO). The medium temperature torrefied biomass (MTTB) yields HGI value in the range of 32e37 that was comparable with HGI of El Cerrejon coal (36e41). A slight change in temperature enabled the torrefied beech wood to be co-milled with coal without capital intensive modification and improved grindability. Comparing the combustion behaviour of single fuels, low temperature torrefied biomass (LTTB) produces less amount of NOx (426 mg/m 3), CO (0.002 mg/m 3) and SO 2 (2 mg/m 3) as compared MTTB and raw beech wood. In the case of co-combustion, it was found that blending of coal with raw biomass does not show a stable behaviour. However, premixing of 50% of coal with 50% of torrefied biomasses (MTTB and LTTB) gives most stable behaviour and reduces NO x almost 30% and SO x up to almost 50% compared to coal. The fly ash contents analysis proved that K 2 O contents much decreased during co-firing of coal and torrefied fuels that could cause ash related issues during combustion of raw biomass.

This study is carried out for a comparative screening of three groups of biomasses; soft or non-woody (peanut shell); intermediate woody (walnut shell) and hard woody (pine wood) for the development of adsorbents/ activated carbons for post-combustion CO 2 capture (over N 2 balance). Three different groups of biomass residues are selected to study the role and nature of the material in adsorption and selection of the raw material for CO 2 adsorbents synthesis for future researches because of the hot issue of anthropogenic CO 2 emissions. The ad-sorption isotherms studied by the thermal gravimetric analyser (TGA) revealed that CO 2 adsorption capabilities are in the range of 2.53-3.92 mmol/g (over N 2 balance) at 25°C. The newly synthesised activated carbons (ACs) exhibited a fast rate of adsorption as 41-94% in the initial 2 min. Porous surface development with catalytic KOH activation is seen clearly through SEM surface morphological analyses and mathematically confirmed from S BET ranges from 146.86 to 944.05 m 2 /g. FTIR and XRD peaks verify the generation of basic or inorganic O 2-rich moieties that help in acidic CO 2 capture. It has also been observed from adsorption isotherms that the order of higher adsorption groups is as; peanut shell > pine wood > walnut shell, while the best activation mass ratio (sample/KOH) is 1:3. The synthesised low cost ACs with an amount of 1.93 US$ per kg production could help to overcome the environmental hazards and problems caused by CO 2 and biomass waste.

Integrated gasification combined cycle (IGCC) power plants have become more attractive after the
emission regulations of the thermal power plants. IGCC power plants enable to control emissions which cause global
warming. Low grade lignites, biomass and wastes can be utilized by this technology. This study deals with the
thermodynamic analysis of an IGCC power plant. Energy and exergy analysis are carried out for a Texaco type
gasifier, one stage, oxygen blown and slurry fed. Cold gas cleaning (fuel gas treatment) system is considered for the
simulations, performed in THERMOFLEX software. A parametric study is also carried out to show the effects of the
O2 purity, fuel supply temperature, gasifier temperature and H2O content of the slurry to the IGCC performance. Net
power and net electric efficiency are calculated to be 389.669 MW and 43.53% respectively. Exergy efficiency of the
simulated IGCC is found to be 40.36% and the highest exergy destruction is observed in gasifier and the combustion
chamber of the gas turbine.

The application of carbon capture and storage (CCS) and carbon neutral techniques should be adopted to reduce the CO 2 emissions from power generation systems. These environmental concerns have renewed interest towards the use of biomass as an alternative to fossil fuels. This study investigates the comparative potential of different power generation systems, including NGCC with and without exhaust gas recirculation (EGR), pulverised su-percritical coal and biomass fired power plants for constant heat input and constant fuel flowrate cases. The modelling of all the power plant cases is realized in Aspen Plus at the gross power output of 800 MW e and integrated with a MEA-based CO 2 capture plant and a CO 2 compression unit. Full-scale detailed modelling of integrated power plant with a CO 2 capture and compression system for biomass fuel for two different cases is reported and compared with the conventional ones. The process performance, in terms of efficiency, emissions and potential losses for all the cases, is analysed. In conclusion, NGCC and NGCC with EGR integrated with CO 2 capture and compression results in higher net efficiency and least efficiency penalty reduction. Further, coal and biomass fired power plants integrated with CO 2 capture and compression results in higher specific CO 2 capture and the least specific losses per unit of the CO 2 captured. Furthermore, biomass with CO 2 capture and compression results in negative emissions.

In order to find the effect of Rasheed Power Plant (RPP) effluents on biodiversity of Tigris River epipelic algal community, twelve monthly clay samples were collected from January to December 2012, at four selected sites along the Tigris River, which were located upstream RPP (S1), near RPP (S2) and down to the impact of RPP discharge (S3) and (S4). The results showed that epipelic cell density range from 60.493 ×10 3 cell /m 3 at S1 to 155.744 × 10 3 cell /m 3 at S2. Shannon diversity index (H) ranged from 0.275-2.517 bit/Ind., species richness (D) ranged from 0.1115-2.1241, species uniformity index (E) ranged from 0.148-2.878. Generally, the biodiversity indicators result showed a positive quantitative effect of thermal effluent on epipelic community, and negative qualitative effect of thermal effluent on its community Also, it was concluded that the benthic clay of Tigris River was considered as poor diversity and polluted especially at site 2.

ABSTRACT The modern Great Basin of the interior western United States is characterized by surface winds with considerable spatial and temporal variabilities. Wind records from the second half of the 20th century for 12 Great Basin localities, analyzed with standard aeolian-sediment transport methods developed elsewhere in the world, reflect this complexity. The drift potential (DP) for aeolian deposits is generally moderate (DP 200– 400) in the western Great Basin and weak (DP b 200) in the central Great Basin where winds are
predominantly west-southwesterly. DP is relatively high (DP N 300) at the eastern edge of the Great Basin where the dominant prevailing wind direction is south-southwesterly. Both DP and resultant drift direction (RDD) are consistent with synoptic meteorological observations of the evolution of cold fronts in the Great Basin. Meteorological observations show that effective winds to produce dunes are most commonly the result of late winter–early spring cyclogenesis. There has been considerable temporal variability of DP in the latter half of the 20th century. Most of the Great Basin has experienced decreasing wind strength since 1973, consistent with recent studies of wind strength in North America and elsewhere. Dune morphology matches both localized RDD and temporal variations in DP reasonably well in the Great Basin. The results demonstrate that local topography can have an important influence on wind directionality, thus providing a cautionary note on the interpretation of dune morphology in the paleoclimatic and stratigraphic record.

Thermal power plants Management safety assessment Case-based reasoning Intelligent decision support system Gray system theory Logistic regression a b s t r a c t Safety assessment of thermal power plants (TPPs) is one of the important means to guarantee the safety of production in thermal power production enterprises. Due to various technical limitations, existing assessment approaches, such as analytic hierarchy process (AHP), Monte Carlo methods, artificial neural network (ANN), etc., are unable to meet the requirements of the complex security assessment of TPPs. Currently, most of the security assessments of TPP are completed by the means of experts' evaluations. Accordingly, the assessment conclusions are greatly affected by the subjectivity of the experts. Essentially, the evaluation of power plant systems relies to a large extent on the knowledge and length of experience of the experts. Therefore in this domain case-based reasoning (CBR) is introduced for the security assessment of TPPs since this methodology models expertise through experience management. Taking the management system of TPPs as breakthrough point, this paper presents a case-based approach for the Safety assessment decision support of TPPs (SATPP). First, this paper reviews commonly used approaches for TPPs security assessment and the current general evaluation process of TPPs security assessment. Then a framework for the Management System Safety Assessment of Thermal Power Plants (MSSATPP) is constructed and an intelligent decision support system for MSSATPP (IDSS-MSSATPP) is functionally designed. IDSS-MSSATPP involves several key technologies and methods such as knowledge representation and case matching. A novel case matching method named Improved Gray CBR (IGCBR) has been developed in which a statistical approach (logistic regression) and Gray System theory are integrated. Instead of applying Gray System theory directly, it has been improved to integrate it better into CBR. In addition this paper describes an experimental prototype system of IDSS-MSSATPP (CBRsys-TPP) in which IGCBR is integrated. The experimental results based on a MSSATPP data set show that CBRsys-TPP has high accuracy and systematically good performance. Further comparative studies with several other common classification approaches also show its competitive power in terms of accuracy and the synergistic effects of the integrated components.

This paper considers the cost savings arising from wind generation through the merit order effect in gross pool electricity markets, using the Irish electricity market as a case study. The
Irish electricity market makes for a good testing ground due to the fact that it is a single market with very little interconnection to other markets, allowing impacts of wind to be more clearly identified than on a more interconnected system. Ireland also has extremely ambitious renewable energy targets, resulting in a high penetration of wind generation.  The authors estimate the historic cost savings arising from wind generation in the Irish electricity market using an hourly time series OLS regression model for 2009. We find that the value of wind to the market dispatch has resulted in savings of €141 million to the market dispatch. We find
that the total costs to the market would have been in the region of 12% higher over the course of the year had no wind output been available. These savings are significantly greater than the
subsidy received for wind-generated electricity over this time period, and as a result it can be seen that the positive externalities derived from wind generated electricity outweigh the cost of the subsidy; particularly when one considers the CO2 saving to the market and accepts that all forms of generation impose integration costs to electricity systems.

How are rising powers affecting global governance? This article analyzes their impact on an important but understudied area of global governance at the intersection of trade and environment: export credit. State-backed export credit agencies (ECAs) play a major role in financing large infrastructure and energy projects, particularly in developing countries. Many of these projects carry significant environmental implications, yet there has been little scholarly attention to their governance. Since the 1990s, global governance of the environmental practices of ECAs has been progressively expanded and strengthened via the OECD Arrangement on export credit and Common Approaches for environmental and social due diligence. Recently, however, there has been a dramatic increase in export credit provision by rising powers, such as India and China, who are not members of the OECD nor subject to the Arrangement or Common Approaches. In this article, I argue that existing governance mechanisms have not caught up with the rapidly changing landscape of export credit. Drawing on the case of India's financing for the Rampal coal-fired power plant in Bangladesh, I show that the problem of environmental governance for export credit increasingly extends beyond the advanced-industrialized states of the OECD. In a context where nearly half of all export credit is now provided by countries outside the OECD, I argue, existing governance mechanisms are no longer sufficient. The failure to cover the large and growing volume of export credit provided by the emerging powers represents a major gap in the established system of environmental governance for export credit.

""Hydrogen embrittlement (HE) of steels is extremely interesting topic in many industrial applications, while a predictive physical model still does not exist. A number of studies carried out in the world are unambiguous confirmation of that statement. Bearing in mind multiple effects of hydrogen in certain metals, the specific mechanism of hydrogen embrittlement is manifested, depending on the experimental conditions. In this paper structural, low carbon steel, for pressure purposes, grade 20 - St.20 (GOST 1050-88) was investigated. Numerous tested samples were cut out from the boiler tubes of fossil fuel power plant, damaged due to high temperature hydrogen attack and HE during service, as a result of the development of hydrogen-induced corrosion process. Samples were prepared for the chemical composition analysis, hardness measurement, impact strength testing (on instrumented Charpy machine) and microstructural characterization by optical and scanning electron microscopy - SEM/EDX. Based on multi-scale special approach, applied in experimental investigations, the results, presented in this paper, indicate the simultaneous action of the hydrogen-enhanced decohesion (HEDE) and hydrogen enhanced localized plasticity (HELP) mechanisms of HE, depending on the local concentration of hydrogen in investigated steel. These results are consistent with some models proposed in literature, about a possible simultaneous action of the HELP and HEDE mechanisms in metallic materials.

In recent years, researchers have proposed transformerless solutions for connecting renewable-energy power plants to the grid. Apart from lack of efficiency and increased cost and weight of the transformer, one of the reasons is the dc input current that causes transformer saturation. The purpose of this paper is the development of a finite-element computational tool that is going to aid transformer manufacturers in designing distribution transformers specifically for the renewable-energy market. It is based on a generalized macroscopic representation of electrical steels used in the transformer manufacturing industry that enables the accurate evaluation of electromagnetic field distribution of transformer cores under heavily saturated conditions. Its advantages over conventional formulations include numerical stability, numerical accuracy, and reduction of iterations of the Newton–Raphson method. An experimental verification of the proposed method is carried out.

The deployment of post-combustion CO 2 capture on large-scale gas-fired power plants is currently progressing, hence the integration of the power and capture plants requires a good understanding of operational requirements and limitations to support this effort. This article aims to assist research in this area, by studying a micro gas turbine (MGT) integrated with an amine-based post-combustion CO 2 capture unit. Both processes were simulated using two different software tools eIPSEpro and Aspen Hysys, and validated against experimental tests. The two MGT models were benchmarked at the nominal condition, and then extended to part-loads (50 and 80 kW e), prior to their integration with the capture plant at flue gas CO 2 concentrations between 5 and 10 mol%. Further, the performance of the MGT and capture plant when gas turbine exhaust gases were recirculated was assessed. Exhaust gas recirculation increases the CO 2 concentration, and reduces the exhaust gas flowrate and specific reboiler duty. The benchmarking of the two models revealed that the IPSEpro model can be easily adapted to new MGT cycle modifications since turbine temperatures and rotational speeds respond to reaching temperature limits; whilst a detailed rate-based approach for the capture plant in Hysys resulted in closely aligned simulation results with experimental data. Crown

Annual carbon dioxide (CO2) emissions from the U.S. power sector decreased 24% from 2000 to2018, while carbon intensity (CO2per unit of electricity generated) declined by 34%. These reductions have been attributed in part to a shift from coal to natural gas, as gas‐fired plants emit roughly half the CO2 emissions as coal plants. To date, no analysis has looked at the coal‐to‐gas shift from the perspective of commitment accounting—the cumulative future CO2 emissions expected from power infrastructure. We estimate that between 2000 and 2018, committed emissions in the U.S. power sector decreased 12% (sixGtCO2), from 49 to 43 GtCO2, assuming average generator lifetimes and capacity factors. Taking into consideration methane leakage during the life cycle of coal and gas plants, this decrease in committed emissions is further offset (e.g., assuming a 3% leakage rate, there is effectively no reduction at all). Thus, although annual emissions have fallen, cumulative future emissions will not be substantially lower unless existing coal and gas plants operate at significantly lower rates than they have historically. Moreover, our estimates of committed emissions for U.S. coal and gas plants find steep reductions in-plant use and/or early retirements are already needed for the country to meet its targets under the Paris climate agreement—even if no new fossil capacity is added.

We present an analytical analysis of a continuous rotor shaft subjected to universal temperature gradients. To this end, an analytical model is derived to investigate the generic thermal vibrations of rotor structures. The analytical solutions are obtained in a rotating frame and include parameters related with both the thermal environment and the rotor dynamic structures. This provides an insight into the mechanisms for the rotor thermal vibration. Furthermore, numerical results based on the analytical solutions are given. An index denoting the temperature gradients is proposed for the occasions with
nonlinear cross-sectional temperature distributions. Finally, the factors influencing the thermal vibrations are analyzed. The results show that the thermal vibration is affected by
many factors including the shaft size, rotational speeds, heating locations, critical speed, etc. Moreover, it is investigated how the convection coefficient and the heat conductivity influence the thermal vibrations in order to provide an insight into the management of thermal vibrations from the perspective of thermal aspects.

Compositional effects on optical band-gap energy using end members of ABO 3 perovskites have been investigated through an optical absorption with a UV-spectroscopy. Three examples are selected, namely, BaTiO 3 -CaTiO 3 , BaTiO 3 -BaZrO 3 , and SrTiO 3 -BaZrO 3 solid solutions. To understand the role of high temperature phase equilibria on the band-gap compositional trends, structural and microscopy data were determined. In simple systems such as Si-Ge, the nonlinear variations in band gap with composition is usually associated with the effect of the local lattice relaxations and provides a parabolic dependence, often referred to as the "bowing" phenomena. In the case of perovskite solutions, the cases are more complex, and a modified Vegard's law is introduced to account for the trends. This has to be considered in relation to high temperature phase formation where incomplete solid solutions and two-phase regions exist. In addition to high temperature phases, low temperature displacive phase transitions and complex nonstoichiometry also perturb the band-gap variation in perovskite oxide materials.

In this study, energy-exergy analysis is performed for the gas-fired combined-cycle power plant which will be constructed in Kuantan and Kapar in the Malay Peninsula in 2020. The main objectives of this current study are first and second law evaluation of the powerplant's main components consisting of the gas turbine unit, condenser, heat recovery steam generator, and triple-pressure steam turbines. By energy-exergy analysis, we can not only evaluate the exact magnitude of exergy destruction and efficiency in each component separately but analyze either major or trivial effects of environment condition variations on plant components. Performance effects are also pinpointed when the pressure ratio, reference temperature, HPT and condenser pressure, reheating and stack temperature change. In the current investigation, more than 808 MW of exergy destruction to the environment mainly occurs in the gas turbine cycle with around 83.79% of total exergy destruction, followed by HRSG (11.3%), steam turbines (roughly 2.58%), and condenser (2.54%). Additionally, exhaust gas fractions from the gas turbine across the combustor are calculated as well wherein the average molar fraction of nitrogen, oxygen, carbon dioxide, and water vapor is calculated to be 76.42%, 17.57%, 1.37%, and 4.64%, respectively. In conclusion, several constructive possibilities for CCPP’s performance development based on the obtained results are introduced. With regard to the construction of this project in 2020, energy-exergy assessment, as well as optimization guidance, can be worthwhile for better modifying some operating conditions and taking advantage of the trivial destruction rate simultaneousl

Corrosion of a T91 steel tube, used in subcritical conditions in an oil power plant for 157,000 hours was characterized 7 mainly through SEM, TEM, EDX and DRX analyses. Severe oxidation and carburization took place in both the outer (boiler) 8 and inner (steam) wall sides. The nature and morphology of the oxide scale multi-layer structure (hematite, magnetite and spinel) 9 depended on the environment exposure. Specific attention was given to the internal oxidation zone (IOZ) at the oxide/metal 10 interface. Diffusion of chromium during the oxidation process was determined, and was proposed to be responsible for the 11 continuous advancement of oxidation to the core of material, which eventually gave rise to the spinel. Finally, in the bulk 12 material, coarsening of the secondary carbides (M 23 C 6) was the main form of microstructural evolution. 13

Solar tower aided coal-fired power generation system (STCG) is able to provide high solar utilization efficiency with low coal consumption rate. This paper compares performances of a solar tower aided coal-fired power plant, a solar tower power plant and a coal-fired power plant under different operative conditions. The comparison includes various solar multiple and thermal energy storage size. According to solar radiation resource and grid power dispatching demand, STCG, solar tower power generation system (STG) and coal-fired power generation system (CPG) work under off-design conditions all the year around. Results show that STCG has higher solar utilization efficiency than STG and lower coal consumption rate and CO 2 emission rate than CPG. In addition, solar-to-electricity exergy efficiency of STCG is at least 1.83% higher than that of STG. Compared to CPG, the 1000 MWe STCG can reduce coal consumption by 2.0 Â 10 5 t/y, with the saving ratio being 10.4%. The annual average coal consumption rate of STCG is 27.3 g/kWh lower than that of CPG. In addition, the annual average CO 2 emission rate of STCG is reduced by 10.1% compared with that of CPG. Solar tower aided coal-fired power generation can facilitate energy conservation and emission reduction of STG and CPG.

This paper addresses the midterm preventive maintenance outage scheduling problem of thermal generating units which is becoming increasingly important due to the aging of power generation fleet. In this context, a novel midterm preventive maintenance outage scheduler is proposed based on decision tree and mixed integer linear formation which explicitly considers the thermal units aging momentum in terms of failure rate. This allows the system operators to determine the thermal units' maintenance outage window based on the cost/benefit analysis of preventive maintenance tasks while optimizing the time interval between consecutive maintenance tasks. Additionally, the division of the year-long midterm horizon into several time blocks in the proposed model provides a unique opportunity for parallel processing and computational saving. The proposed approach is tested on the IEEE Reliability Test System (IEEE-RTS). The results presented reveal the accuracy and efficiency of the proposed approach.

The proper interference fit between the joined parts is a prerequisite for an effective pressure joint. The main purpose of the pressure joint is to transfer tangential, radial and axial loads between the joined parts. In order to provide proper functioning of the machine assembly (whose component parts are connected by the pressure joints), i.e. the transfer of loads without skidding, it is essential to determine the pressure joints interference fit parameters. The new methodology for the conveyor idlers pressure joints quality control is presented in this paper. The procedure for the analytical determination of the expected disassembling force (limiting value) in the pressure joints between the shaft-rolling bearing and the bearing-idler shell is described in detail. The analytically calculated boundary values are compared with the experimental ones. According to the presented criteria, the evaluation of the conveyor idler fits quality was performed and reliable conclusions were successfully adopted.

In many countries throughout the world, fly and bottom ashes originating from coal-fired thermal power plants are declared as wastes requiring special care during reuse and disposal. In this regard, a number of toxicity tests have been developed to assess the metal leaching potential of ash residues. In this study, fly ash samples obtained from the Ç atalagzı thermal power plant, located on the northwestern coast of Turkey, were subjected to toxicity tests such as the extraction (EP) and toxicity characteristic leaching (TCLP) procedures of the U.S. Environmental Protection Agency (U.S. EPA), and the so-called Method A extraction procedure of the American Society of Testing and Materials (ASTM). The results observed for the extracts were compared with each other and the selected tests were evaluated in terms of their use in representing leaching under natural field conditions.

This paper presents modeling and impact analysis of wind farms in Jeju island power system, which is made of wind farms, a current source-type high-voltage, direct current (HVDC) system, and thermal power plants. In this paper, four kinds of major components are modeled: a total of 88 MW wind farms, a 300 MW HVDC system, thermal power plants, and the Jeju power system load. To analyze the impact of the wind power generation to the Jeju power system, simulation is carried out for two case studies by using the PSCAD/EMTDC program. One is for the steady-state operation under different wind speed, and the other is for the transient-state operation when all wind farms are disconnected suddenly from the Jeju power grid due to the wind speed higher than the rated value. These comparative studies have been effective in accessing the impact of wind power generation on the Jeju island power system stability.