• Energy Research
• 7. Clean energy close
• 3. Good health close
• 1. No poverty close
• CA close
• Hyper Article en Ligne close

The transportation impact on pollution and global climate change, has forced the automotive sector to search for more ecological solutions. Owing to the different properties of Fuel Cell (FC), real potential for reducing vehicles’ emissions has been witnessed. The optimization of FC integration within Electric Vehicles (EVs) is one of the original solutions. This paper presents an innovating solution of multi-stack Fuel Cell Electrical Vehicle (FCEV) in terms of efficiency, durability and ecological impact on environment. The main objective is to illustrate the interest of using the multi-stack FC system on the global autonomy, cycling, and efficiency enhancement, besides optimizing its operation performance.

AbstractInterest in underwater acoustic sensor networks (UW‐ASNs) has rapidly increased with the desire to control the large portion of the world covered by oceans. Energy efficiency is one of the major concerns in UW‐ASNs due to the limited energy budget of the underwater sensor nodes. In this paper, we tackle the problem of energy holes in UW‐ASNs while taking into consideration the unique characteristics of the underwater channel. We prove that we can evenly distribute the transmission load among sensor nodes provided that sensors adjust their communication range when they send or forward the periodically generated data. In particular, we propose a balanced routing strategy along with the associated deployment pattern that meticulously determines the load weight for each possible next hop that leads to fair energy consumption among all underwater sensors. Consequently, the energy holes problem is overcome, and hence, the network lifetime is improved. To the best of our knowledge, this is the first work that addresses the energy hole problem in UW‐ASNs. Copyright © 2016 John Wiley & Sons, Ltd.

The Author(s) 2015. This article is published with open access at Springerlink.com Abstract This study investigates ultra-thin transparent conducting oxides (TCO) of indium tin oxide (ITO), alu- minum-doped zinc oxide (AZO) and zinc oxide (ZnO) to determine their viability as candidate materials for use in plasmonic-enhanced thin-film amorphous silicon solar photovoltaic (PV) devices. First a sensitivity analysis of the optical absorption for the intrinsic layer of a nano-disk patterned thin-film amorphous silicon-based solar cell as a function of TCO thickness (10-50 nm) was performed by simulation. These simulation results were then used to guide the design of the experimental work which investi- gated both optical and electrical properties of ultra-thin (10 nm on average) films simultaneously deposited on both glass and silicon substrates using conventional rf sputter- ing. The effects of deposition and post-processing param- eters on material properties of ITO, AZO and ZnO ultra- thin TCOs were probed and the suitability of TCOs for integration into plasmonic-enhanced thin-film solar PV devices was assessed. The results show that ultra-thin TCOs present a number of challenges for use as thin top contacts on plasmonic-enhanced PV devices: (1) optical and electrical parameters differ greatly from those of thicker (bulk) films deposited under the same conditions, (2) the films are delicate due to their thickness, requiring very long annealing times to prevent cracking, and (3) reactive gases require careful monitoring to maintain sto- ichiometry. The results presented here found a trade-off between conductivity and transparency of the deposited films. Although the sub 50 nm TCO films investigated exhibited desirable optical properties (transmittance greater than 80 %), their resistivity was too high to be considered as materials for the top contact of conventional PV devices. Future work is necessary to improve thin TCO properties, or alternative materials, and geometries are needed in plasmonic-based amorphous silicon solar cells. The sta- bility of ultra-thin TCO films also needs to be experi- mentally investigated under normal device operating conditions.

Relying on real options theory, we employ a multistage decision model to analyze the effect of delaying the introduction of emission trading systems (ETS) on power plant investments in carbon capture and storage (CCS) retrofits, on plant operation, and on carbon dioxide (CO2) abatement. Unlike previous studies, we assume that the investment decision is made before the ETS is in place, and we allow CCS operating flexibility for new power plant investments. Thus, the plant may be run in CCS-off mode if carbon prices are low. We employ Monte Carlo simulation methods to account for uncertainties in the prices of CO2 certificates, other inputs, and output prices, relying on a realistic parameterization for a supercritical pulverized coal plant in China. We find that CCS operating flexibility lowers the critical carbon price needed to support CCS investment because it renders CCS investment less irreversible. For a low carbon price path, operating flexibility also implies that delaying the introduction of an ETS hardly affects plant CO2 abatement since the plant operator is better off purchasing emission certificates rather than operating the plant in CCS mode. Interestingly, for low carbon prices we find a U-shaped relation between the length of the delay and the economic value of the plant. Thus, delaying the introduction of an ETS may make investors worse off.

Lignocellulosic biomass is a sustainable source of renewable substrate to produce low carbon footprint energy and materials. Biomass conversion is usually performed in two steps: a biomass pretreatment for improving cellulose accessibility followed by enzymatic hydrolysis of cellulose. In this study we investigated the efficiency of a bioextrusion pretreatment (extrusion in the presence of cellulase enzyme) for production of reducing sugars from corn crop agricultural residues. Our results demonstrate that bioextrusion increased the reducing sugar conversion yield by at least 94% at high solid/liquid ratio (14%-40%). Monitoring biomass surface with carbohydrate-binding modules (FTCM-depletion assay) revealed that well known negative impact of high solid/liquid ratio on conversion yield is not due to the lack of exposed cellulose which was abundant under such conditions. Bioextrusion was found to be less efficient on alkaline pretreated biomass but being a mild and solvent limiting pretreatment, it might help to minimize the waste stream.

The recent development of small scale combined heat and power (CHP) systems has provided the opportunity for in-house power backup of residential-scale photovoltaic (PV) arrays. This paper investigates the potential of deploying a distributed network of PV + CHP hybrid systems in order to increase the PV penetration level in the U.S. The temporal distribution of solar flux, electrical and heating requirements for representative U.S. single family residences were analyzed and the results clearly show that hybridizing CHP with PV can enable additional PV deployment above what is possible with a conventional centralized electric generation system. The technical evolution of such PV + CHP hybrid systems was developed from the present (near market) technology through four generations, which enable high utilization rates of both PV-generated electricity and CHP-generated heat. A method to determine the maximum percent of PV-generated electricity on the grid without energy storage was derived and applied to an example area. The results show that a PV + CHP hybrid system not only has the potential to radically reduce energy waste in the status quo electrical and heating systems, but it also enables the share of solar PV to be expanded by about a factor of five.

This review article compiles the various advances made since 2008 in sustainable high-rate anaerobic technologies with emphasis on their performance enhancement when treating agro-food industrial wastewater. The review explores the generation and characteristics of different agro-food industrial wastewaters; the need for and the performance of high rate anaerobic reactors, such as an upflow anaerobic fixed bed reactor, an upflow anaerobic sludge blanket (UASB) reactor, hybrid systems etc.; operational challenges, mass transfer considerations, energy production estimation, toxicity, modeling, technology assessment and recommendations for successful operation