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Abstract A CFD modelling study has been undertaken to examine the co-firing of pulverised coal and biomass with particular regard to the burnout of the larger diameter biomass particles. Computations were based on a research combustion facility that replicates an industrial coal-fired power station. Three percent, by mass, of pinewood was blended with a bituminous UK coal, and the effects of the wood particle size and shape on the burnout of the combined wood and coal char were investigated. The effect of varying the devolatilisation and char combustion rate constants for the biomass component in the blend was also investigated. It was concluded that the combustion of small (200 μm) wood particles was rapid but the rate of combustion of larger particles was dependent on their composition, size, and shape.

The Severn Estuary has the world's second largest tide range and a barrage across the estuary, located just seawards of Cardiff in Wales and Weston in the South West England, has been proposed for over half a century, with the objective of extracting large amounts of tidal energy. A Severn Barrage, as previously proposed by the Severn Tidal Power Group (STPG), would be the largest renewable energy project for tidal power generation in the world, if built as proposed, and would generate approximately 5% of the UK's electricity needs. However, concerns have been raised over the environmental impacts of such a barrage, including potential increase in flood risk, loss of intertidal habitats etc. In addressing the challenges of maximizing the energy output and minimizing the environmental impacts of such a barrage, this research study has focused on using a Continental Shelf model, based on the modified Environmental Fluid Dynamics Code (EFDC) with a barrage operation module (EFDC_B), to investigate both the far and near field hydrodynamic impacts of a barrage for different operating scenarios. Three scenarios have been considered to simulate the Severn Barrage, operating via two-way generation and using different combinations of turbines and sluices. The first scenario consisted of 216 turbines and 166 sluices installed along the barrage; the second consisted of 382 turbines with no sluices; and the third consisted of 764 turbines and no sluices. The specification of the sluice gates and turbines are the same for all scenarios. The model results indicate that the third scenario has the best mitigating effects for the far-field and near-field flood risks caused by a barrage and produces the most similar results of minimum water depth and maximum velocity distributions to those obtained from simulating the natural conditions of the estuary, i.e. the current conditions. The results also show that the flow patterns around the barrage are closest to those for the existing natural conditions with minimal slight changes in the estuary. Thus, the results clearly indicate that the environmental impacts of a Severn Barrage can be minimized if the barrage is operated for two-way generation and under the third scenario. Although it appears that the energy output for the third scenario is less than that obtained for the other two scenarios, if very low head (VLH) turbines are used, then the third scenario could generate more energy as more turbines could be cited along the barrage structure. Therefore, the study shows that a Severn Barrage, operating in two-way generation and with 764 turbines (ideally VLH turbines), would be the best option to meet the needs of maximizing the energy output, but having a minimal impact on environmental changes in the estuary and far-field.

Abstract The adoption rate and stringency of building energy standards in the U.S. have been increasing since the mid-1990s as a result of the Energy Policy Act mandate of 1992 (EPAct). Current evidence on the energy savings that accrue from commercial building energy standards is based on engineering simulations, which do not account for realized behaviour once a standard is actually adopted. This paper uses quasi-experimental variation in commercial building energy standard adoptions to estimate their effect on realized electricity consumption and cost-effectiveness. In states induced by EPAct to adopt an energy standard where all new nonresidential construction was erected under a commercial standard, electricity consumption per service worker is lower by about 12%, and total commercial electricity consumption is lower by 10%. Including early adopters and never-adopters to the analysis leads to a downward bias in the treatment effect. The realized electricity savings in the EPAct states represent three quarters of predicted simulated savings, and electricity saved in 2010 came at a cost of approximately 7.7 cents per kWh.

Abstract For 118 million residential housing units in the U.S., there is currently a gap between the potential energy savings that can be achieved through the use of existing energy efficiency technologies, and the actual level of energy savings realized, particularly for the 37% of housing units that are considered residential rental properties. Additional quantifiable benefits are needed beyond energy savings to help further motivate residential property owners to invest in energy efficiency upgrades. This research focuses on assessing the adoption of energy efficient upgrades in U.S. residential housing and the impact on rental prices. Ten U.S. cities are chosen for analysis; these cities vary in size across multiple climate zones, and represent a diverse set of housing market conditions. Data was collected for over 159,000 rental property listings, their characteristics, and their energy efficiency measures listed in rental housing postings across each city. Following an extensive data quality control process, over thirty different types energy efficient features were identified. The level of adoption was determined for each city, ranging from 5.3% to 21.6%. Efficient lighting and appliances were among the most common, with many features doubling as energy efficient and other desirable aesthetic or comfort improvements. Then using propensity score matching and conditional mean comparison methods, the relative impact on rent charged in each city was calculated, which ranged from a 6% to 14.1% increase in rent for properties with energy efficient features, demonstrating a positive economic impact of these features, particularly for property owners. This was further subdivided into five types of energy efficiency upgrade and three housing types. Single family homes generally demanded higher premiums with energy efficient features, however there was not a consistent pattern across the types of efficient upgrades. The results of this work demonstrate that investment in energy efficient technologies has quantifiable benefits for rental property owners in the U.S. beyond just energy savings. This methodology and results can also be used in other cities and by property owners, utility companies, or others, ultimately encouraging further investment and positive economic impact in residential energy efficiency and in turn improving energy and resource conservation in the building sector.

Abstract A new formulation for the evaporation, flashing, condensation processes taking place in the effects of thermal desalination systems which simulates the operation of both forward and parallel/cross configurations is coupled with an exergo-economic model based on the SPECO method. The thermo-economic model uses accurate properties for the seawater, brine, pure water and vapour and is solved with an equation solver which does not require the development of a specific solution algorithm as in most previous studies. This flexible model is used to analyze the influence of the number of effects N and the temperature difference ΔT e between effects on the technical and economic performance of multi-effect desalination systems with ejector vapour compression. In particular, it is shown that the performance calculated by an earlier black-box approach is not attainable by technically and economically realistic systems. It is also shown that for each feed configuration and a given number of effects there exists an optimum value of ΔT e which minimizes the cost of the produced potable water. This last result forms the basis of a procedure that combines black-box results with the optimum value of ΔT e and can be used to select the appropriate system for any specific application.

Abstract The rapid increase in energy demand and the limited resources of fossil fuel as well as the environmentally damaging effects, drive the world to find new options for sustainable electricity generation, which is represented by renewable energies. Concentrating solar power (CSP) is one of the most promising technologies in the field of electricity generation to tackle this issue with a competitive cost in the future. This paper presents an investigation of the potential of implementation of CSP plants in Libya. The socio-economic context, current energy situation of the country and different types of CSP plants are discussed. Moreover, an assessment of site parameters required for CSP plants including solar resources, land use and topography, water resources and grid connections are investigated in detail. In addition, thermo-economic simulation of a 50 MW parabolic trough power plant is performed. The simulation is conducted based on meteorological data measured by the weather station installed at the Centre for Solar Energy Research and Studies (CSERS) in Tajoura city. The performance results are compared with the reference plant Andasol-1 in Spain. Even though the proposed plant is located on the North coast where solar resources are at their minimum compared with other regions of the country, the outcome of the study proves that Libya is not only suitable but it can be economically competitive in the implementation of CSP technology.

Abstract This study develops a novel sustainability assessment methodology for energy systems using life-cycle emission factors and sustainability indicators. Here, the global warming and environmental impact dimensions of the sustainability assessment methodology are examined in detail. A comparative analysis shows that a wind-battery system produces fewer potential global warming, stratospheric ozone depletion, air pollution, and water pollution impacts compared to a gas-fired system. The wind-battery system generates 13% of the life-cycle GHG emissions and 22% of the life-cycle ozone-depleting substance emissions of a gas-fired power plant. Nitrous oxide contributes more than 90% of the stratospheric ozone depletion potential of gas-fired and wind-battery systems.

For zero‐defect wave soldering of double‐sided and multilayer printed circuit boards, the copper through‐hole‐plating must be impervious to gas generated in the laminate for the period of a few seconds while the solder is molten. The kinetics of the gas evolution during soldering have been related quantitatively to the integrity of the plated copper. This in turn is related to the quality of the electroless copper (evaluated using the backlighting test), the nature and distribution of the catalyst (evaluated using X‐ray photoelectron spectroscopy) and the methods and effectiveness of the hole‐wall preparation (evaluated using scanning electron microscopy). The relevance of laboratory measurements has been confirmed on a wide range of industrial production plating lines.

Abstract— The odd nucleoside 4‐thiouridine, which is present in position 8 of 70% of E. coli tRNAs, possesses unusual spectroscopic properties which make it suitable for intramolecular energy transfer studies. Both its luminescence excitation spectrum and the action spectrum (230–380 nm) for the 8–13 link formation have been established in native E. coli tRNA at room temperature. The spectra are identical and present a new unexpected peak around 260 nm. At this wavelength, they are amplified by a factor of nine as compared with the absorption and excitation spectra of the free nucleoside in aqueous solution.The origin of this new peak is discussed and it is concluded that energy transfer does occur from the common nucleosides to the 4‐thiouridine residue. Using the values of the nucleosides to 4‐thiouridine distances inferred from the sets of atomic coordinates obtained on yeast tRNAphe crystals, a satisfactory account of our finding can be obtained assuming singlet‐singlet energy transfer. The efficiency of the mechanism is probably favoured by a good overlap between the emission spectra of the common nucleosides and the absorption spectrum of 4‐thiouridine.