Fossil Fuels

Geological carbon dioxide storage (CCS) has the potential to make a significant contribution to the decarbonisation of the UK. Amid concerns over maintaining security, and hence diversity, of supply, CCS could allow the continued use of coal, oil and gas whilst avoiding the CO 2 emissions currently associated with fossil fuel use. This project has explored some of the geological, environmental, technical, economic and social implications of this technology. The UK is well placed to exploit CCS with a large offshore storage capacity, both in disused oil and gas fields and saline aquifers. This capacity should be sufficient to store CO 2 from the power sector (at current levels) for a least one century, using well understood and therefore likely to be lower-risk, depleted hydrocarbon fields and contained parts of aquifers. It is very difficult to produce reliable estimates of the (potentially much larger) storage capacity of the less well understood geological reservoirs such as non-confined parts of aquifers. With the majority of its large coal fired power stations due to be retired during the next 15 to 20 years, the UK is at a natural decision point with respect to the future of power generation from coal; the existence of both national reserves and the infrastructure for receiving imported coal makes clean coal technology a realistic option. The notion of CCS as a 'bridging' or 'stop-gap' technology (i.e. whilst we develop 'genuinely' sustainable renewable energy technologies) needs to be examined somewhat critically, especially given the scale of global coal reserves. If CCS plant is built, then it is likely that technological innovation will bring down the costs of CO 2 capture, such that it could become increasingly attractive. As with any capitalintensive option, there is a danger of becoming 'locked-in' to a CCS system. The costs of CCS in our model for UK power stations in the East Midlands and Yorkshire to reservoirs in the North Sea are between £25 and £60 per tonne of CO 2 captured, transported and stored. This is between about 2 and 4 times the current traded price of a tonne of CO 2 in the EU Emissions Trading Scheme. In addition to the technical and economic requirements of the CCS technology, it should also be socially and environmentally acceptable. Our research has shown that, given an acceptance of the severity and urgency of addressing climate change, CCS is viewed favourably by members of the public, provided it is adopted within a portfolio of other measures. The most commonly voiced concern from the public is that of leakage and this remains perhaps the greatest uncertainty with CCS. It is not possible to make general statements concerning storage security; assessments must be site specific. The impacts of any potential leakage are also somewhat uncertain but should be balanced against the deleterious effects of increased acidification in the oceans due to uptake of elevated atmospheric CO 2 that have already been observed. Provided adequate long term monitoring can be ensured, any leakage of CO 2 from a storage site is likely to have minimal localised impacts as long as leaks are rapidly repaired. A regulatory framework for CCS will need to include risk assessment of potential environmental and health and safety impacts, accounting and 1 monitoring and liability for the long term. In summary, although there remain uncertainties to be resolved through research and demonstration projects, our assessment demonstrates that CCS holds great potential for significant cuts in CO 2 emissions as we develop long term alternatives to fossil fuel use. CCS can contribute to reducing emissions of CO 2 into the atmosphere in the near term (i.e. peak-shaving the future atmospheric concentration of CO 2 ), with the potential to continue to deliver significant CO 2 reductions over the long term.

While research and development of algal biofuels are currently receiving much interest and funding, they are still not commercially viable at today's fossil fuel prices. However, a niche opportunity may exist where algae are grown as a by-product of high rate algal ponds (HRAPs) operated for wastewater treatment. In addition to significantly better economics, algal biofuel production from wastewater treatment HRAPs has a much smaller environmental footprint compared to commercial algal production HRAPs which consume freshwater and fertilisers. In this paper the critical parameters that limit algal cultivation, production and harvest are reviewed and practical options that may enhance the net harvestable algal production from wastewater treatment HRAPs including CO 2 addition, species control, control of grazers and parasites and bioflocculation are discussed.

Objectives: The health effects of chronic low-dose radiation exposure remains a controversial question. Monitoring after the Chernobyl nuclear accident in Ukraine suggested that chronic low-dose radiation exposure was not linked to cancer mortality among the general population. However, elevated rates of birth defects in contaminated compared to uncontaminated regions suggest that exposure to radiation in utero might impact development and that chronic radiation exposure might represent an underestimated risk to human health.

Of the five principal global carbon pools, the ocean pool is the largest at 38.4 trillion metric tons (mt) in the surface layer, followed by the fossil fuels (4.13 trillion mt), soils (2.5 trillion mt to a depth of one meter), biotic (620 billion mt), and atmospheric pools (800 billion mt). If the fluxes among terrestrial pools are combined, annual total carbon flows across the pools average around 60 billion mt, with managed ecosystems (croplands, grazing lands, and plantations) accounting for 57 percent of that total. Thus, land managers have custody of more annual carbon flows than any other group.

Y. Kominami). a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / a g r f o r m e t 0168-1923/$ -see front matter # a g r i c u l t u r a l a n d f o r e s t m e t e o r o l o g y 1 4 8 ( 2 0 0 8 ) 7 2 3 -7 3 7

Thiobacillus denitrijicans is a strictly autotrophic and facultative anaerobe first described in detail by Baalsrud and Baalsrud. ' Under anaerobic conditions nitrate may be used as a terminal electron acceptor with reduction to elemental nitrogen. Thiosulfate, elemental sulfur, and sulfide may be used as energy sources with oxidation to sulfate; however, sulfide is an inhibitory substrate. Sublette and S y l v e~t e r~.~ have demonstrated that T. denitrijicans may be readily cultured anaerobically in batch and continuous reactors on H2S(g) under sulfide limiting conditions. Under these conditions sulfide concentrations in the culture medium were less than IpM resulting in very low concentrations in the reactor outlet gas (less than 0.05pM). The stoichiometry of the anaerobic oxidation of H2S(g) in batch and continuous cultures was reported and stable reactor operation demonstrated at reactor loadings as high as 4-5 mmol H2S oxidized/h/g biomass. Maximum H2S loading of the biomass was estimated at 5.4-7.7 mmol H2S/h/g biomass under sulfide limiting conditions. Sublette and S y l v e~t e r~,~ have proposed a process for the microbial desulfurization of natural gas based on the oxidation of H2S(g) by Thiobacillus denitrijicans. The proposed process could be greatly simplified if aseptic operation of the reactor was not required. Accordingly, we report here a study of the effects of heterotrophic contaminants on H2S(g) oxidation by T. denitrijicans.

As the collection of end-of-life (EOL) electrical and electronic products from households and businesses increases around the world, the search for economically and environmentally responsible and sustainable recovery and recycling processes intensifies ...

CO 2 capture and storage from energy conversion systems is one option for reducing power plant CO 2 emissions to the atmosphere and for limiting the impact of fossil-fuel use on climate change. Among existing technologies, chemical looping combustion (CLC), an oxy-fuel approach, appears to be one of the most promising techniques, providing straightforward CO 2 capture with low energy requirements. This paper provides an evaluation of CLC technology from an economic and environmental perspective by comparing it with to a reference plant, a combined cycle power plant that includes no CO 2 capture. Two exergy-based methods, the exergoeconomic and the exergoenvironmental analyses, are used to determine the economic and environmental impacts, respectively. The applied methods facilitate the iterative optimization of energy conversion systems and lead towards the improvement of the effectiveness of the overall plant while decreasing the cost and the environmental impact of the generated product. For the plant with CLC, a high increase in the cost of electricity is observed, while at the same time the environmental impact decreases.

Renewabl e energy (RE) has been co nsidered as one of the stro nger co nte nders to imp rove the pli gh t of nearl y two billion peopl e, mostly in rura l areas, w itho ut access to mod ern forms of ene rgy. A ltho ugh the econo mics of renewab le energy technolog ies (RETs) have ye t to reac h a stage w he re these co uld rep lace foss il fue ls on a sig nificant sca le, man y experts arg ue that technolog ies suc h as so lar, w ind, and small-scale hyd ropower are no t only econo mica lly v iab le but also ideal for rural areas. T he mism atch between the pot enti al and ac tua l use of RE ca n be attributed to ba rriers in its impl em entation. A mo ng othe rs, a lack of financing has been one of the important bar rie rs adverse ly affect ing the wi des prea d use of RET s. In develop ing co unt ries , a majority of initia tives have focused on fin an cial incent ives. T he re are successes as we ll as fa ilures fro m the models ado pte d. The paper discu sses probl em s related to fina nc ing RETs, by foc us ing on small-scale off-grid RETs in deve lop ing countr ies , and reviews so me of th ese model s to bring out the lesson s that we can lea rn to accelerate the ava ilabi lity of fina nce to RETs.

Forested tropical peatlands in Southeast Asia store at least 42 000 Million metric tonnes (Mt) of soil carbon. Human activity and climate change threatens the stability of this large pool, which has been decreasing rapidly over the last few decades owing to deforestation, drainage and fire. In this paper we estimate the carbon dioxide (CO 2 ) emissions resulting from drainage of lowland tropical peatland for agricultural and forestry development which dominates the perturbation of the carbon balance in the region. Present and future emissions from drained peatlands are quantified using data on peatland extent and peat thickness, present and projected land use, water management practices and decomposition rates. Of the 27.1 Million hectares (Mha) of peatland in Southeast Asia, 12.9 Mha had been deforested and mostly drained by 2006. This latter area is increasing rapidly because of increasing land development pressures. Carbon dioxide (CO 2 ) emission caused by decomposition of drained peatlands was between 355 Mt y −1 and 855 Mt y −1 in 2006 of which 82% came from Indonesia, largely Sumatra and Kalimantan. At a global scale, CO 2 emission from peatland drainage in Southeast Asia is contributing the equivalent of 1.3% to 3.1% of current global CO 2 emissions from the combustion of fossil fuel. If current peatland development and management practices continue, these emissions are predicted to continue for decades. This warrants inclusion of Correspondence to: A. Hooijer ([email protected]) tropical peatland CO 2 emissions in global greenhouse gas emission calculations and climate mitigation policies. Uncertainties in emission calculations are discussed and research needs for improved estimates are identified.

Biofuels have been considerably developed as a probable alternative resource of fossil fuel. In recent times, the continuously increasingdemand and prices of fossil fuel as well asclimate change, makes biodiesel and bioethanol as the only key target for future energy market especially in transportation sector.A large amount of biodiesel and bioethanol productions cost belongs to feedstock that makes it to be as an essential issue for the future of biofuel. The significance of feedstock will be increased while it derives from food feedstock.The purpose of this paper is to describe various type of biodiesel and bioethanol feedstock. Apart from that, this paper will also attempt to compare the biodiesel and bioethanol respect to feedstock.

Like all industrialised countries, Belgium accepted to diminish its greenhouse gas emissions in the frame of the Kyoto agreement. On top of the list ®gures CO 2. A major emission source for CO 2 is burning fossil fuels. As the residential sector accounts for 28% of the country's annual energy consumption and as this consumption mainly concerns fossil fuels, it has an equally important share in the CO 2 release. Hence, at ®rst sight, the best policy for a decrease is by improving the energy ef®ciency. The question to be solved, however, is which improvement could generate the reduction needed? This study discusses a methodology and comments simulations that help in answering that question. The results are not as simple as one should like. The housing stock in fact acts as a conservatory system. For the case being, the impact of energy ef®cient new construction on the CO 2 release remains quite marginal if the period considered does not extend beyond a decade. The effect becomes signi®cant only over a longer period, on condition that more stringent energy ef®ciency measures are combined with a shift from new construction to retro®t and reconstruction. Also a diminishing increase in the number of households may help in reducing energy consumption and CO 2 release.

If energy security is defined as the availability of energy at all times in various forms, in sufficient quantities and at affordable prices, without unacceptable or irreversible impact on the economy and the environment, Japan is facing an energy security predicament. For a country that was already uneasy about energy security, the March 11, 2011 earthquake and tsunami, which caused a nuclear catastrophe in TEPCO's Fukushima Daiichi nuclear power plant, turned this unease into outright anxiety. With the temporary and/or permanent ...

Energy projects may profoundly impact Indigenous peoples. We consider effects of Canada's proposed Trans Mountain oil pipeline expansion on the health and food sovereignty of the Tsleil-Waututh Nation (TWN) through contamination and impeded access to uncontaminated traditional foods. Federal monitoring and TWN documentation show elevated shellfish biotoxin levels in TWN's traditional territory near the terminus where crude oil is piped. Although TWN restoration work has reopened some shellfish-harvesting sites, pipeline expansion stands to increase health risk directly through rising bioaccumulating chemical toxins as well as through increased hazardous biotoxins. Climate change from increased fossil fuel use, expected via pipeline expansion, also threatens to increase algae blooms through higher temperature and nutrient loading. As the environmental impact assessment process failed to effectively consider these local health concerns in addition to larger impacts of climate change, new assessment is needed attending to linked issues of equity, sustainability and Indigenous food sovereignty.

The present study aims to analyze the discourse of management and policy-making in the field of electricity in the country to study and analyze the text of 100 interviews, lectures, statements and quotations conducted in this regard in the years after the revolution; Based on the theory of Laclau and Moff discourse,it focuses on specific themes and their elaboration Thus, first the main themes and axes of policymakers' discourse were extracted and then it was determined which themes have a special position and how they are placed in that discourse according to other themes. The main themes and axes of the dominant discourse entitled "Development based on the abundance of fossil resources in the country" are: "Sustainable electricity supply", "Self-sufficiency and self-reliance in the electricity industry", "Economic supply of electricity" and "Poverty alleviation and justice", have been elaborated around the central slab of "fossil fuel-based development". Analyzing the discourse of policymakers showed that they see the issues of electricity supply in the context of the "fossil electricity discourse" which is at the heart of "fossil fuel development". In this way, all their actions become meaningful in the context of the fossil regime discourse, and this discourse has been able to marginalize other sub-discourses, whether modifying or opposing the use of this energy, restructuring the electricity, nuclear and renewable industries, and this discource masters its concepts and achieves hegemony.

Using fossil fuels is likely to remain the dominant means of producing electricity in 2030 and even 2050, partly because power stations have long lives. There are two main ways of reducing CO 2 emissions from fossil-fuelled power plants. These are carbon capture and storage (CCS), which can produce near-zero CO 2 emissions, and increases in plant efficiency, which can give rise to significant reductions in CO 2 emissions and to reduced costs. If a typical UK coal-fired plant was replaced by today's best available technology, it would lead to reductions of around 25% in emissions of CO 2 per MW h of electricity produced. Future technologies are targeting even larger reductions in emissions, as well as providing a route, with CCS, to zero emissions. These two routes are linked and they are both essential activities on the pathway to zero emissions. This paper focuses on the second route and also covers an additional third route for reducing emissions, the use of biomass. It discusses the current status of the science and technologies for fossil-fuelled power generation and outlines likely future technologies, development targets and timescales. This is followed by a description of the scientific and technological developments that are needed to meet these challenges. Once built, a power plant can last for over 40 years, so the ability to upgrade and retrofit a plant during its lifetime is important.

Polycyclic aromatic hydrocarbon (PAH) concentrations in 34 surface sediments along the Susquehanna River were investigated in 2000. The total concentrations of PAHs in the surface sediments of Lake Clarke, Lake Aldred, the upper Conowingo Reservoir, and the lower Conowingo Reservoir were 3.3 ± 1.5 lg g À1 (n = 9), 1.6 ± 1.3 lg g À1 (n = 4), 9.8 ± 5.5 lg g À1 (n = 7), and 4.0 ± 1.2 lg g À1 (n = 14), respectively. These represent the first comprehensive measurement of PAHs in Susquehanna River surface sediments. Overall, total PAH concentrations were relatively lower in Lake Aldred, which is more shallow and sloped, and significantly higher in the upper Conowingo Reservoir. The sediment PAH levels were related to river flow rates, which are indirectly correlated with the particle size of the surface sediments. Total PAH levels in all the studied sites were below the effects range median (ERM) of 44.8 lg g À1 with 38% (13 of the 34 sampling sites) exceeding the effects range low (ERL) of 4.02 lg g À1 . Principal component analysis indicated that variations in the PAH compound patterns of each reservoir decreased from upstream to downstream, indicating that the surface sediments were mixed along the Susquehanna River. The PAH patterns in the lower Conowingo Reservoir sediments were a combination of those upstream sources. Source analysis using isomer ratios as indicators suggested that PAHs in the Susquehanna River surface sediment are derived from the combustion of fossil fuels such as coal and gasoline with coal as the major source of contaminants.

Recently radiocarbon ( 14 C) concentration in the atmospheric CO 2 has decreased over time due to the exchange of CO 2 between atmosphere and ocean, but also due to emission of 14 C free-CO 2 from burning fossil fuels. The second contribution, known as the Suess effect, can be observed in the highly industrialized and/or urban area. 14 C concentrations in annual rings of a pine tree from the urban area in Nagoya, Japan, that grew over the last 24 years were measured with AMS to be remarkably lower than those observed in ''clear air'' of corresponding years at Schauinsland station in Germany. The measured data were used to estimate the rate of the fossil component in atmospheric CO 2 that was derived from fossil fuel burning. Exponential and linear functions were fitted to the secular variations of 14 C concentration in annual rings to calculate the decay constant and an average decreasing rate of 14 C concentration. The result suggests that the use of annual rings of trees to obtain the secular variations of 14 C concentration of atmospheric CO 2 can be useful and efficient for environmental monitoring and modeling of the carbon distribution in local scale.

When investigating the toxicity of individual particle sources, it is important to consider the contribution of both primary and secondary particles. In this article, we present the design of a new photochemical chamber that can be used to form secondary sulfuric acid particles from diluted coal-fired power plant emissions. The chamber is a relatively small, well-mixed flow reactor that can fit in a mobile reaction laboratory. It produces high concentrations of hydroxyl radical (OH) from the photolysis of ozone (O 3 ) in the presence of water vapor. Two chambers were built and tested. A pilot chamber was tested in the laboratory, using mixtures of NO and SO 2 in air, at concentrations that are approximately 100 times lower than those in power plant stack emissions. This chamber was able to oxidize about 20% of the SO 2 , thereby producing 1350 μg m −3 of H 2 SO 4 particles. Further tests showed that increasing O 3 concentrations and residence time increased the H 2 SO 4 production. A field chamber was built subsequently and used in a toxicological study. Diluted coal-fired power plant emissions were introduced in the chamber. Over 19 days of exposure, the chamber, on average, converted 17% of the supplied SO 2 emissions and produced an average of 350 μg m −3 of H 2 SO 4 particles. Particle losses were determined for the pilot chamber, using artificial particles whose size ranged from 50 to 1000 nm. The determined losses ranged from 21 to 42%, with no trend between the amount of particle loss and particle size. Losses for the field chamber, estimated using model calculations, were found to be similar to those of the pilot chamber.

The research programme called "international research cooperation and organic integrity" was commenced for a period 2006-2010. It is coordinated by DARCOF (The Danish Research Centre for Organic Farming). The whole programme, with acronym DARCOF III, consists of 15 projects (http://www.darcof.dk/research/darcofiii/index.html). One of them is BIOCONCENS -Biomass and bioenergy production in organic farming -consequences for soil fertility, environment, spread of animal parasites and socio-economy (http://www.bioconcens.elr.dk/uk/). The production of bioenergy in organic agriculture (OA) can reduce its dependency of fossil fuels and decrease green house gasses emission; consequently it will increase sustainability of organic farms. Biorefinery concept based on co-production of biogas, bioethanol and protein fodder in organic farming will be developed within the BIOCONCENS project and the background for the project and the different work packages will be presented in this paper.

AbstractÐIncreased atmospheric CO 2 , caused partly by burning fossil fuels, is assumed to elevate the risk of global warming, while nitrate contamination of surface runo and groundwater from fertilizer and agricultural wastes constitutes a serious environmental hazard on a regional scale. Switchgrass (Panicum virgatum L.) grown as an energy crop could reduce atmospheric CO 2 accumulation by replacing fossil fuels and sequestering C. It could also improve soil productivity by C sequestration, and reduce xy À1 3 contamination of water by absorbing N lost from fertilizer and agricultural waste if planted in ®lter strips on adjacent land. The objective of this study was to assess potential impacts of switchgrass on C and N balances by reviewing and synthesizing information from current literature, unpublished data and on-going research. Replacing fossil fuels with switchgrass, or any other biomass, will have a much greater eect on atmospheric CO 2 than C sequestration. This is because replacing fossil fuels provides a cumulative eect, while C sequestration oers only a one-time bene®t. Furthermore, switchgrass will provide net gains in C sequestration only if it replaces annual row crops, but not if it replaces grazed pasture. Nitrogen recovery by switchgrass in an Alabama study was 65.6%, which compares favorably with the 50% recovery frequently quoted as the norm for wheat (Triticum aestivum L.) and corn (Zea mays L). #

The Intergovernmental Panel on Climate Change (IPCC) has stated that stabilizing atmospheric CO 2 concentrations will require reduction of global greenhouse gas (GHG) emissions by as much as 80% by 2050. Subnational efforts to cut emissions will inform policy development nationally and globally. We projected GHG mitigation strategies for Minnesota, which has adopted a strategic goal of 80% emissions reduction by 2050. A portfolio of conservation strategies, including electricity conservation, increased vehicle fleet fuel efficiency, and reduced vehicle miles traveled, is likely the most cost-effective option for Minnesota and could reduce emissions by 18% below 2005 levels. An 80% GHG reduction would require complete decarbonization of the electricity and transportation sectors, combined with carbon capture and sequestration at power plants, or deep cuts in other relatively more intransigent GHGemitting sectors. In order to achieve ambitious GHG reduction goals, policymakers should promote aggressive conservation efforts, which would probably have negative net costs, while phasing in alternative fuels to replace coal and motor gasoline over the long-term.

The atmospheric CO 2 concentration is increasing, due primarily to fossil-fuel combustion and deforestation. Sequestering atmospheric C in agricultural soils is being advocated as a possibility to partially offset fossil-fuel emissions. Sequestering C in agriculture requires a change in management practices, i.e. efficient use of pesticides, irrigation, and farm machinery. The C emissions associated with a change in practices have not traditionally been incorporated comprehensively into C sequestration analyses. A full C cycle analysis has been completed for agricultural inputs, resulting in estimates of net C flux for three crop types across three tillage intensities. The full C cycle analysis includes estimates of energy use and C emissions for primary fuels, electricity, fertilizers, lime, pesticides, irrigation, seed production, and farm machinery. Total C emissions values were used in conjunction with C sequestration estimates to model net C flux to the atmosphere over time. Based on US average crop inputs, no-till emitted less CO 2 from agricultural operations than did conventional tillage, with 137 and 168 kg C ha −1 per year, respectively. Changing from conventional tillage to no-till is therefore estimated to both enhance C sequestration and decrease CO 2 emissions. While the enhanced C sequestration will continue for a finite time, the reduction in net CO 2 flux to the atmosphere, caused by the reduced fossil-fuel use, can continue indefinitely, as long as the alternative practice is continued. Estimates of net C flux, which are based on US average inputs, will vary across crop type and different climate regimes. The C coefficients calculated for agricultural inputs can be used to estimate C emissions and net C flux on a site-specific basis. Published by Elsevier Science B.V.

Integration/co-firing with existing fossil fuel plants could give near term highly efficient and low cost power production from biomass. This paper presents a techno-economical analysis on options for integrating biomass thermal conversion (optimized for local resources w50 MW th) with existing CCGT (combined cycle gas turbine) power plants (800e1400 MW th). Options include hybrid combined cycles (HCC), indirect gasification of biomass and simple cycle biomass steam plants which are simulated using the software Ebsilon Professional and Aspen Plus. Levelized cost of electricity (LCoE) is calculated with cost functions derived from power plant data. Results show that the integrated HCC configurations (fullyfired) show a significantly higher efficiency (40e41%, LHV (lower heating value)) than a stand-alone steam plant (35.5%); roughly half of the efficiency (2.4% points) is due to more efficient fuel drying. Because of higher investment costs, HCC options have cost advantages over stand-alone options at high biomass fuel prices (>25 EUR/MWh) or low discount rates (<5%). Gasification options show even higher efficiency (46e50%), and the lowest LCoE for the options studied for fuel costs exceeding 10 EUR/MWh. It can be concluded that clear efficiency improvements and possible cost reductions can be reached by integration of biomass with CCGT power plants compared to stand-alone plants.

A Geographical Information System (GIS) based methodology has been used to construct the black carbon (BC) emission inventory for the Indian geographical region. The distribution of emissions from a broader level to a spatial resolution of 1°Â 1°grid has been carried out by considering micro level details and activity data of fossil fuels and bio-fuels. Our calculated total BC emissions were 1343.78 Gg and 835.50 Gg for the base years 2001 and 1991 respectively with a decadal growth of around 61%, which is highly significant. The district level analysis shows a diverse spatial distribution with the top 10% emitting districts contributing nearly 50% of total BC emission. Coal contributes more than 50% of total BC emission. All the metropolitan cities show high BC emissions due to high population density giving rise to high vehicular emissions and more demand of energy.

Physical-chemical processes for the capture and sequestration of CO 2 from fossil fuelfired power plant flue-gases are very expensive. Biological processes for CO 2 utilization involve plant photosynthesis and conversion of the biomass to fuels, with no net CO 2 production. Terrestrial plants cannot utilize flue gas CO 2 directly. Only submerged aquatic plants, particularly microalgae, can utilize CO 2 from power plant flue gases in a practical process. Microalgae have the potential for achieving high productivities and can be converted to gaseous and liquid fuels. A preliminary cost-analysis of such a process is presented that suggests that, if high productivities are achievable, overall costs would compare favorably with alternative physical-chemical processes for flue gas CO 2 capture and sequestration, but would be higher than CO 2 mitigation with terrestrial plants. Microalgae CO 2 utilization systems would be most applicable where land and water (seawater, brackish) resources, not readily utilized by agriculture, are available.

A series of experiments was conducted to study the effect of twisted-tape width on the heat transfer and pressure drop with laminar flow in tubes. Data for three twisted-tape wavelengths, each with five different widths, have been collected with constant wall temperature boundary condition. Correlations for the friction factor and Nusselt number are also available. The correlations predict the experimental data to within 10 to 15 percent for the heat transfer and friction factor, respectively. The presence of the twisted tape has caused the friction factor to increase by a factor of 3 to 7 depending on Reynolds number and the twisted-tape geometry. Heat transfer results have shown an increase of 1.5 to 3 times that of plain tubes depending on the flow conditions and the twisted-tape geometry. The width shows no effect on friction factor and heat transfer in the low range of Reynolds number but has a more pronounced effect on heat transfer at the higher range of Reynolds number. It i...

The Straits of Malacca, along the west coast of Peninsular Malaysia, is one of the busiest waterways in the world with about 2000 vessels passing through it per month, of which about 25 percent are oil tankers of varying sizes . In the course of their passage, the practices of tanker ballasting and pumping of bilges by non-tanker vessels result in considerable pollution in these waters. Collisions and groundings also cause oil spills in Malaysian waters. Oil contaminants not only pollute the high seas but also affects the near-coastal waters. Marine oil pollution, in particular that of near-coastal waters, may also be attributed to land-based activities such as the utilisation of petroleum related products, the direct discharge of untreated municipal and industrial wastes containing refined and partly weathered oils to sewers and rivers, and the discharge of effluents from refineries and other similar sources.

Climate change is arguably the greatest threat to society as power plants, the single largest human source of heat-trapping pollution, continue to emit massive amounts of carbon into the atmosphere. Sociologists have identified several possible structural determinants of electricity-based CO 2 emissions, including international trade and global normative regimes, national political–legal systems, and organizational size and age. But because they treat these factors as competing predictors, scholars have yet to examine how they might work together to explain why some power plants emit vastly more pollutants than others. Using a worldwide data set of utility facilities and fuzzy-set methods, we analyze the conjoint effects of global, political, and organizational conditions on fossil-fueled plants' CO 2 emissions. Findings reveal that hyperpolluters' emission rates are a function of four distinct causal recipes, which we label coercive, quiescent, expropriative, and inertial configurations, and these same sets of conditions also increase plants' emission levels.

The total energy and fossil fuels used in producing a desktop computer with 17-in. CRT monitor are estimated at 6400 megajoules (MJ) and 260 kg, respectively. This indicates that computer manufacturing is energy intensive: the ratio of fossil fuel use to product weight is 11, an order of magnitude larger than the factor of 1-2 for many other manufactured goods. This high energy intensity of manufacturing, combined with rapid turnover in computers, results in an annual life cycle energy burden that is surprisingly high: about 2600 MJ per year, 1.3 times that of a refrigerator. In contrast with many home appliances, life cycle energy use of a computer is dominated by production (81%) as opposed to operation (19%). Extension of usable lifespan (e.g. by reselling or upgrading) is thus a promising approach to mitigating energy impacts as well as other environmental burdens associated with manufacturing and disposal.

This report discusses past, current and projected mercury emissions to the atmosphere from major industrial sources, and presents a first assessment of the contribution to the regional mercury budget from selected natural sources. Emissions (1995 estimates) from fossil fuels combustion ð29:8 t yr À1 Þ, cement production ð28:8 t yr À1 Þ and incineration of solid wastes ð27:6 t yr À1 Þ, all together account for about 82% of the regional anthropogenic total ð105:7 t yr À1 Þ. Other industrial sources in the region are smelters ð4:8 t yr À1 Þ, iron-steel plants ð4:8 t yr À1 Þ and other minor sources (chlor-alkali plants, crematoria, chemicals production) that have been considered together in the miscellaneous category ð9:6 t yr À1 Þ. Regional emissions from anthropogenic sources increased at a rate of 3% yr À1 from 1983 to 1995 and are projected to increase at a rate of 1:9% yr À1 in the next 25 years, if no improvement in emission control policy occurs. On a country-by-country basis, France is the leading emitter country with 22:6 t yr À1 followed by Turkey ð16:1 t yr À1 Þ, Italy ð11:4 t yr À1 Þ, Spain ð9:1 t yr À1 Þ, the former Yugoslavia 7:9 ðt yr À1 Þ, Morocco ð6:9 t yr À1 Þ, Bulgaria ð6:8 t yr À1 Þ, Egypt ð6:1 t yr À1 Þ, Syria ð3:6 t yr À1 Þ, Libya ð2:9 t yr À1 Þ, Tunisia ð2:8 t yr À1 Þ and Greece ð2:7 t yr À1 Þ, whereas the remaining countries account for less than 7% of the regional total. The annual emission from natural sources is 110 t yr À1 , although this figure only includes the volatilisation of elemental mercury from surface waters and emissions from volcanoes, whereas the contribution due to the degassing of mercury from top soil and vegetation has not been included in this first assessment. Therefore, natural and anthropogenic sources in the Mediterranean region release annually about 215 t of mercury, which represents a significant contribution to the total mercury budget released in Europe and to the global atmosphere. #

Yemen is a least developed arid country located in the Middle East within the Arabian Peninsula’s southern end. Currently, it entirely relies almost on gas and crude oil for the country’s entire energy sources. However, Yemen has a huge potential for the production of renewable and alternative energy sources including wind and solar energy productions as confirmed by the country’s Ministry of Electricity & Energy. This project reviews how the country can benefit from solar power production and also examines how such an alternative energy source policy might mitigate the requirement to construct new fossil fuel generating powers in the country.

1] Black carbon (BC), the product of incomplete combustion of fossil fuels and biomass (called elemental carbon (EC) in atmospheric sciences), was quantified in 12 different materials by 17 laboratories from different disciplines, using seven different methods. The materials were divided into three classes: (1) potentially interfering materials, (2) laboratory-produced BC-rich materials, and (3) BC-containing environmental matrices (from soil, water, sediment, and atmosphere). This is the first comprehensive intercomparison of this type (multimethod, multilab, and multisample), focusing mainly on methods used for soil and sediment BC studies. Results for the potentially interfering materials (which by definition contained no fire-derived organic carbon) highlighted situations where individual methods may overestimate BC concentrations. Results for the BC-rich materials (one soot and two chars) showed that some of the methods identified

Combined heat and power Corn ethanol Corn stover Greenhouse gas emissions Life cycle assessment Zea mays a b s t r a c t A life-cycle assessment (LCA) of corn ethanol was conducted to determine the reduction in the life-cycle greenhouse gas (GHG) emissions for corn ethanol compared to gasoline by integrating biomass fuels to replace fossil fuels (natural gas and grid electricity) in a U.S. Midwest dry-grind corn ethanol plant producing 0.19 hm 3 y À1 of denatured ethanol. The biomass fuels studied are corn stover and ethanol co-products [dried distillers grains with solubles (DDGS), and syrup (solubles portion of DDGS)]. The biomass conversion technologies/systems considered are process heat (PH) only systems, combined heat and power (CHP) systems, and biomass integrated gasification combined cycle (BIGCC)