The effect of anode flow characteristics and temperature on the performance of a direct methanol fuel cell

The effect of anode flow characteristics and temperature on the performance of a direct methanol fuel cell

06 Electrical power supply and utilization (scientific, technical) Relating residential and commercial sector electricity loads to climate-evaluati...

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06 Electrical

power supply and utilization (scientific,

technical)

Relating residential and commercial sector electricity loads to climate-evaluating state level sensitivities and vuinerabiiities 02/01515

Sailor, D.I. Energy, 2001, 26, (7), 645-657. A methodology for relating climate parameters to electricity consumption at regional scales has been applied to eight states resulting in predictive models of per capita residential and commercial electricity consumption. In isolating residential and commercial consumption these models allow for detailed analyses of urban electricity demand and its vulnerabilities to climate change at regional scales. Model sensitivities to climate perturbations and specific climate change scenarios have been investigated providing first-order estimates of how electricity demand may respond to climatic changes. The results indicate a wide range of electricity demand impacts, with one state experiencing decreased loads associated with climate warming, but the others experiencing a significant increase in annual per capita residential and commercial electricity consumption. The results indicate significantly different sensitivities for neighbouring states, suggesting the inability to generalize results. In the long run the nonclimatic factors responsible for these differences must be incorporated into the model structure, and assessments of changes in market saturation and related factors need to be included to make it amenable to long range forecasting. 02lO1516 Renewable energy systems based on hydrogen for remote applications

Agbossou, K. ef al. Journal of Power Sources, 2001, 96, (I), 168-172. An integrated renewable energy (RE) system for powering remote communication stations and based on hydrogen is described. The system is based on the production of hydrogen by electrolysis whereby the electricity is generated by a 10 kW wind turbine (WT) and 1 kW photovoltaic (PV) array. When available, the excess power from the RE sources is used to produce and store hydrogen. When not enough energy is produced from the RE sources, the electricity is then regenerated from the stored hydrogen via a 5 kW proton exchange membrane fuel cell system. Overview results on the performances of the WT, PV, and fuel cells system are presented. 02/01517

Requirement for metals of electric vehicle

batteries

R&de, I. and Andersson, B.A. Journal of Power Sources, 2001, 93, (I2), 55-71. The purpose of this paper is to review the requirement for potentially scarce or hazardous metals used in a wide range of electric vehicle batteries, in order to provide datasets that could be used as a basis for a variety of assessments of electric vehicles and batteries, such as lifecycle assessments (LCA) and material availability assessments. It is an explicit objective to make the calculations and assumptions transparent so that the datasets can easily be recalculated with different assumptions. The requirement for metals of nine types of batteries was investigated: Li-metal(V), Li-ion(Mn, Ni and Co), NaNiCI, NiMH(AB2 and ABs), NiCd and PbA, which contain seven potentially scarce or hazardous metals/group of metals: lithium, nickel, cobalt, vanadium, cadmium, lead and mischmetal (rare-earth elements). We provide datasets for both near-term and improved technology of the requirement for metals per kWh battery as well as per battery electric vehicle.

SOFCs are then introduced as the 200 kW class system developed by the American project. After these demonstrations, developments for larger power plants will start around 2005. High temperature fuel cells are also expected to utilize coal as a fuel in future, therefore, the demonstrations and commercialization of the natural gas fuelled large fuel cell power plants are highly desirable for their importance.

02fO1520 The Bourner lecture - do standby batteries need to have a new chemistry?

Karlsson, G. Journal of Power Sources, 2001, 96, (I), xvii-xx. The telecommunication and data communication businesses are experiencing strong growth and so is the demand for batteries for back-up power. The stationary lead-acid battery is the type that This presentation will give some dominates these applications. guidelines for battery scientists who want to apply their technology to back-up power. The opinion of the author is that the advanced batteries that are in the frontline today are poorly adapted to the needs of back-up power for networks. If developers of these advanced batteries are to stand a chance of achieving success in the network ;;;yo;arket they must focus on reliability, volumetric energy density

02/01521 The effect of anode flow characteristics and temperature on the performance of e direct methanol fuel cell

Amphlett, J.C. er al. Journal of Power Sources, 2002, 96, (I), 204-213. An experimental direct methanol fuel cell (DMFC), designed and manufactured in-house, was used in this study. The cell is of standard filter-press configuration with parallel rectangular single-pass anode channels. The membrane electrode assembly (MEA), with a suitable Pt-Ru anode electrocatalyst, was purchased from E-TEK Inc. A 1.0 M methanol in water solution was used as the fuel and pure oxygen was used as the oxidant in all experiments. Three graphite anode plates were machined with the same flow channel configuration but each with different depth of channels. The cathode was kept the same for all experiments. Polarization curves and ac impedance spectra were obtained for varying temperatures and channel depths. To separate the contribution of the oxygen reduction reaction to the overvoltage from the anode and membrane contributions, reference hydrogen electrode (RHE) measurements were taken. By comparing the RHE polarization with the methanol-oxygen polarization experiments, it was found that polarization losses at the oxygen cathode accounted for a 40-50% of the overpotential. The variation in the performance of the cell with flow of methanol/water mix, with temperature and with current density was studied. Polarization measurements indicate that the medium channel depth flow channels performed better than either the shallow depth or deep depth flow channels indicating that there is a complex relationship between the effect of flow velocity and the influence of the rate of production of product CO*. AC impedance spectroscopy measurements confirmed the observed polarization results. This method proved to be able to provide a reliable indication of the performance of the cell even when the cell had not yet achieved steady-state. In the case of the shallow channel depth anode, ac impedance revealed that it required considerably longer to achieve steady-state than the time required for the medium and deep channel depths.

02/01516 Rh based catalysts for indirect internal reforming ethanol applications in molten carbonate fuel ceils Freni, S. Journal of Power Sources, 2001, 94, (I), 14-19. The feasibility of coupling a processor for internal indirect reforming of ethanol/water with molten carbonate fuel cells has been verified by several experiments. Two different Rh/A1203 catalysts have been prepared and characterized. Several tests to measure the catalytic activity on ethanol steam reforming process have been performed both on alumina and supported catalysts. The tests evidenced that ethanol can be decomposed and steam reforming process can be obtained at well-determined conditions of temperature and catalyst load. The 5% Rh/AlzO, catalyst produced, at 923 K, hydrogen rich gas mixture, than can be considered of high interest for molten carbonate fuel cell applications because it is free from any production of ethylene or other undesirable products. Further, this interest has been confirmed by the good results obtained in the long-term tests carried out on the 5% Rh/ Al203 catalyst.

02/01519

The application to the fuel ceil power generations

Watanabe, T. Nippon Enerugi Gakkaishi, 2001, 80, (6), 396-401. (In Japanese) The recent development status of high temperature fuel cells fuelled by natural gas is described, especially for MCFCs and SOFCs. These fuel cell pow& plants are expected tb attain very high efficiency and are very effective in reducing the emission of COz. For the present, it is supposed that MCFCs are initially introduced as the 300 kW class system developed by the NED0 program or American project and the

194

Fuel and Energy Abstracts

May 2002

02/01522 Transition strategies for solar thermal power generation Mills, D.R. and Dey, C.J. [email protected] Proc. - ISES Sol. World Congr., 2000, 1, 272-279. Edited by Grossman G. A strategy for solar thermal power generation by using thermal injection into existing coal-fired power plants is investigated. Hybridization of solar heat with fossil plant can be carried out either as simple fuel substitution, or through creation of additional firm capacity. In developed economies where there are no significant capacity shortages on electricity grid systems, the largest initial solar thermal market can be considered to be small solar fraction retrofitting of existing fossil capacity. In this way, relatively low cost CO2 emission reductions can be achieved in the transition years when fossil fuel capacity is still predominant. This and other hybridization strategies are compared by using costs of parabolic through, central receiver, and new compact linear fresnel reflector (CLFR) technology. For CLFR arrays, the cost of emissions savings from solar supplementation of an existing coalfired power plant is calculated to be 50 US%/t for a fuel cost of 0.02 US$/kWh,. This is significantly lower than the emissions saving costs of other solar thermal electricity options such as integrated combine cycle plants (-160 US$/t). Although coal fuel saving is only an interim strategy, the emissions reductions from the solar utilization of existing steam turbine equipment present an attractive and simple transition strategy for achieving high volume production of solar components which can also be used by stand-alone solar thermal systems.