Life cycle assessment of shale gas in the UK

The remarkable US growth of shale gas and the associated decrease in the US natural gas prices has catalysed an increasing interest of shale gas resource exploration in other areas of the world. Commercial drilling operations have not yet commenced, but exploration is taking place in some European countries, including the UK. Major environmental concerns, regarding the amount and the handling method of the emissions associated with hydraulic fracturing, the disposal of waste water and the low well productivity, have pushed some countries to ban exploration and trials. We contextualized the shale gas extraction to the UK condition where the estimate of recoverable gas has made the debate on shale gas highly interesting. We used the methodology of Life Cycle Assessment (LCA) and estimated the environmental burden of shale gas production, processing and distribution at low pressure to the consumer. In this paper we have reported the detailed hot spot analysis of the impact of shale gas on the watersheds

Quattordicesimo Rapporto dell’Osservatorio della Congiuntura Turistica nella Provincia di Brescia: novembre 2012

Report relativo al sondaggio Congiuntur Consuntivo Estate 201

Life cycle assessment of shale gas, LNG and waste in the future UK energy mix

This thesis investigates the environmental impacts of novel energy sources and technologies developing in the UK in the near future. The life cycle assessment methodology (LCA) is applied to advanced energy systems in order to develop a comprehensive framework able to identify the most promising energy supplies, in the context of an increased focus on low carbon technologies and the requirement of a stable and secure energy supply. The outcomes of this study provide valuable information to stakeholders and policy makers to be correctly informed, and can help in planning new policy legislations or tune the existing ones. The evolution of the UK energy mix through the recent past till the current times is analysed. Key sources and technologies for the future energy supply are identified and reviewed. Their environmental burdens are not currently quantified; hence, this study develops a number of different LCA models for a future, aware, energy development. First, the study uniquely approaches the LCA analysis of shale gas and Liquefied Natural Gas (LNG) for the UK as they are expected to play an important role in the future UK energy mix. After that, within the framework of diverting waste from landfill and produce renewable energy, the environmental impacts of an advanced gasification-plasma technology for electricity production are analysed for the treatment of different feedstocks. The technology is compared to other advanced and conventional waste-to-electricity technologies, including pyrolysis and combustion. Bio-Substitute natural gas (Bio-SNG) production from waste through advanced thermal technologies is then studied within the context of de-carbonising the gas grid. This process is compared to biological processes for biomethane production from waste according to current and future energy mixes. The outcomes of this research do not identify a unique trend. The context in which the analysed technologies operate, the basis of the comparisons between different alternatives and the approached perspective of the study, characterize the interpretation of the obtained results. The environmental models developed in this study are suitable for the environmental assessments of energy mixes of different countries. The framework developed also identifies the boundaries, the flows and the alternative scenarios to be considered in parallel social and economic life cycle thinking studies

The Active Corona of HD 35850 (F8 V)

We present Extreme Ultraviolet Explorer spectroscopy and photometry of the nearby F8 V star HD 35850 (HR 1817). The EUVE spectra reveal 28 emission lines from Fe IX and Fe XV to Fe XXIV. The Fe XXI 102, 129 A ratio yields an upper limit for the coronal electron density, log n < 11.6 per cc. The EUVE SW spectrum shows a small but clearly detectable continuum. The line-to-continuum ratio indicates approximately solar Fe abundances, 0.8 < Z < 1.6. The resulting emission-measure distribution is characterized by two temperature components at log T of 6.8 and 7.4. The EUVE spectra have been compared with non-simultaneous ASCA SIS spectra of HD 35850. The SIS spectrum shows the same temperature distribution as the EUVE DEM analysis. However, the SIS spectral firs suggest sub-solar abundances, 0.34 < Z < 0.81. Although some of the discrepancy may be the result of incomplete X-ray line lists, we cannot explain the disagreement between the EUVE line-to-continuum ratio and the ASCA-derived Fe abundance. Given its youth (t ~ 100 Myr), its rapid rotation (v sin i ~ 50 km/s), and its high X-ray activity (Lx ~ 1.5E+30 ergs/s), HD 35850 may represent an activity extremum for single, main-sequence F-type stars. The variability and EM distribution can be reconstructed using the continuous flaring model of Guedel provided that the flare distribution has a power-law index of 1.8. Similar results obtained for other young solar analogs suggest that continuous flaring is a viable coronal heating mechanism on rapidly rotating, late-type, main-sequence stars.Comment: 32 pages incl. 14 figures and 3 tables. To appear in the 1999 April 10 issue of The Astrophysical Journa

Life cycle assessment of a polymer electrolyte membrane fuel cell system for passenger vehicles

In moving towards a more sustainable society, hydrogen fueled polymer electrolyte membrane (PEM) fuel cell technology is seen as a great opportunity to reduce the environmental impact of the transport sector. However, decision makers have the challenge of understanding the real environmental consequences of producing fuel cell vehicles (FCVs) compared to alternative green cars, such as battery electric vehicles (BEVs). and more conventional internal combustion engine vehicles (ICEVs). In this work, we presented a comprehensive life cycle assessment (LCA) of a FCV focused on its manufacturing phase and compared with the production of a BEV and an ICEV. For the manufacturing phase, the FCV inventories started from the catalyst layer to the glider, including the hydrogen tank. A sensitivity analysis on some of the key components of the fuel cell stack and the FC system (such as balance-of-plant and hydrogen tank) was carried out to account for different assumptions on materials and inventory models. The production process of the fuel cell vehicle showed a higher environmental impact compared to the production of the other two vehicles power sources. This is mainly due to the hydrogen tank and the fuel cell stack. However, by combining the results of the sensitivity analysis for each component - a best-case scenario showed that there is the potential for a 25% reduction in the climate change impact category for the FCV compared to a baseline FCV scenario. Reducing the environmental impact associated with the manufacture of fuel cell vehicles represents an important challenge. The entire life cycle has also been considered and the manufacturing, use and disposal of FCV, electric vehicle and conventional diesel vehicle were compared. Overall, the ICEV showed the highest GWP and this was mainly due to the use phase and the fossil carbon emissions associated to the use of diesel

Statistical Approach to Fiber Laser Microcutting of NIMONIC® C263 Superalloy Sheet Used in Effusion Cooling System of Aero Engines

AbstractIn order to reduce thermal stress and avoid premature failure of turbine blades in the hot section of aero-engines, a diffusion cooling system is often adopted. This system is a thin sheet, with a closely spaced holes array allowing a uniform cooling of the turbine blade thanks to the evenly distributing of the cooling fluid within its wall. The holes diameters vary in the range of 0.3-1.0 mm. Furthermore, tight tolerances, perpendicular surfaces, no burr, no recast layer, are required. In order to satisfy the hole requirements, typically EDM technique is adopted. However, EDM micro-drilling needs long process time (about 20 s for hole). A promising alternative is laser trepanning. In this technique, a laser beam, with a very small focused spot, is used to make a hole by circular cutting. The hole is obtained in few seconds (<3 s). In this work a preliminary study on laser microcutting of NIMONIC® C263 sheet is presented in order to verify the possibility to adopt a low-power Yb:YAG fiber laser for the microdrilling. Linear cutting tests were carried out on NIMONIC® C263 superalloy sheet, 0.38 mm thick, using a 100 W Yb:YAG fiber laser working in modulated regime. A systematic approach based on Design of Experiment (DoE) has been successfully adopted with the aim to detect which and how the process parameters affect the kerf geometry in term of kerf width, taper angle and tolerances. The examined process parameters were scan speed, on-time, pulse duration and gas pressure. A full factorial design and ANalysis Of VAriance (ANOVA) were applied. Experimental results show the possibility to obtain kerf characterized by narrow width (<100 μm), low taper angle values (<1.8°) and small tolerance (<0.22 μm). Then, the possibility to produce in-tolerance holes was proved

A laboratory measurement of meteor luminous efficiency

Laboratory measurement of meteor luminous efficienc

Life cycle assessment of conventional and advanced two-stage energy-from-waste technologies for methane production

This study integrates the Life Cycle Assessment (LCA) of thermal and biological technologies for municipal solid waste management within the context of renewable resource use for methane production. Five different scenarios are analysed for the UK, the main focus being on advanced gasification-plasma technology for Bio Substitute natural gas (Bio-SNG) production, anaerobic digestion and incineration. Firstly, a waste management perspective has been taken and a functional unit of 1 kg of waste to be disposed was used; secondly, according to an energy production perspective a functional unit of 1 MJ of renewable methane produced was considered. The first perspective demonstrates that when the current energy mix is used in the analysis (i.e. strongly based on fossil resources), processes with higher electric efficiency determine lower global warming potential (GWP). However, as the electricity mix in the UK becomes less carbon intensive and the natural gas mix increases the carbon intensity, processes with higher Bio-SNG yield are shown to achieve a lower global warming impact within the next 20 years. When the perspective of energy production is taken, more efficient technologies for renewable methane production give a lower GWP for both current and future energy mix. All other LCA indicators are also analysed and the hot spot of the anaerobic digestion process is performed