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Abstract A portable commercial solid-oxide fuel cell that consisted of 56 stacked cells and used an indirect internal reforming strategy with a rhodium catalyst on an yttria-stabilized zirconia structure for its reformer and a nickel anode on an yttria-stabilized zirconia structure electrolyte was tested with propane fuel intentionally blended with 0 to 15 ppmv H2S. The voltages of cell pairs and stack were recorded during 7-h poison and recovery tests. Results indicated that with higher H2S concentrations, the rate of stack voltage decrease could vary from 181.4 mV/h at 3 ppmv to 432.0 mV/h at 15 ppmv. The voltage losses of individual cell pairs showed a consistent trend as well. Results from recovery tests indicated that a longer recovery time may be necessary at higher H2S concentration. Electrochemical impedance spectroscopy was employed to better understand the role of varying phenomena within the solid-oxide fuel cell. An equivalent circuit model was constructed to fit electrochemical impedance spectral data that was taken at the system level. Effects of individual components within the system (fuel cell, battery, and DC/DC converter), determined by using electrochemical impedance spectra, were then used to deduce the behaviour of the SOFC. A clear charge transfer resistance increase was observed due to H2S poisoning, consistent with the blocking of active sites on the catalyst in the anode layer. The effect was found to be completely reversible by a period of operation with sulfide-free fuel.

Geoenergy sources will continue to be mainstays of the world’s energy mix for many years to come, but the technological and business realities behind these energy sources are changing in two fundamental ways. First, with much of the world’s “easy oil” already consumed, the companies behind geoenergy will have to use increasingly sophisticated technologies to find and deliver these energy sources to the market. Second, the expectations placed upon the geoenergy sector by many of its stakeholders have grown considerably with regards to environmental stewardship, safety, and human welfare. In the face of these kinds of challenges, the industry will require an increasing degree of technological and commercial sophistication to continue to be a part of the world’s sustainable energy mix. Blockchain has emerged as a promising innovation that could potentially play an important role in delivering the kinds of technological and commercial capabilities that the geoenergy sector will need to achieve these ends. In spite of the myriad ways that blockchain could potentially improve the efficiency and sustainability of the geoenergy industry, however, the technology is still evolving, and a few barriers stand in the way of its widespread deployment. This paper puts forward case study evidence from the Intel Corporation and the Energistics Consortium showing what the geoenergy sector can learn about blockchain from other industries, and highlights that the absence of data standards and interoperability has contributed to blockchain’s failure to deliver significant value in the geoenergy domain thus far.

Abstract Within residences, normative messaging interventions have encouraged households to engage in various pro-environmental behaviors. In norm-based intervention campaigns, it is hypothesized that more personally relevant reference groups increase norm adherence, thus improving the effectiveness of normative messaging interventions. Advanced energy grid infrastructure, such as smart meters and cloud computing, enables the creation of highly personalized behavioral reference groups in a non-invasive manner by dynamically classifying households into highly similar user groups based on usage patterns. Unfortunately, it remains unclear how readily available data on household energy use and housing characteristics affect the classification performance of dynamic behavioral reference groups. Therefore, this research evaluates the classification performance of dynamic behavioral reference groups using readily available data. An energy-cyber-physical system for personalized normative messaging interventions is trained and tested using one-year of energy use data from 2248 households in Holland, Michigan. Dynamic behavioral reference group classification proved very accurate, 94.7–95.9% for weekly feedback and 89.9–93.1% for monthly feedback using only readily available data. In addition, using more historical energy use data contributes to enhancing classification accuracy. Lastly, high classification performance for each behavioral reference group is achieved at 97.6% of precision, recall and F1-score. With the proposed system, it is possible to dynamically assign highly personalized behavioral reference groups to households every billing cycle even if behavioral patterns are subject to change. Thus, interveners will be able to deploy personalized normative feedback messages on a large scale.

Abstract Tar abatement and removal is most challenging facing industrialization of biomass gasification technology and its cost-effective removal is indispensably dreamed. Thorough, low-cost and stable removal of toluene, a major compound of biomass tar, was achieved by the microwave catalytic reforming method. A self-designed microwave tube furnace was employed, and toluene was converted with char-supported nickel-iron and nickel-cerium catalysts in an ex situ hot gas conditions. Under the optimal conditions, a 100% toluene conversion efficiency could be achieved, and the hydrogen concentration in the product gas could reach 28.2 vol%. The energy efficiency was 98.97 g/kW h. According to duration tests, the conversion efficiency of nickel-cerium catalysts could still be higher than 90%, even after 8-h successive runs. Comprehensive characterizations of fresh and spent catalysts were conducted, showing agglomeration was the main challenge instead of carbon deposition, which was previously commonly believed. Furthermore, in the pursuit of advancing industrial tar abatement, the depletion and thermal stability of char-supported catalysts were evaluated through a custom-designed gasification-atmosphere-thermogravimetry-mass spectrum analysis. The study provided a breakthrough for the integration of thermal, catalysis and microwave effects for toluene conversion, and the mechanism of char-supported catalysis under specific microwave conditions was also highlighted.

Abstract As our energy systems are transitioning towards low-carbon energy sources and their environmental and economic sustainability are assessed, their potential social impacts must also be determined. These social impacts may be disproportionate to a population, leading to energy justice concerns. The social life cycle assessment framework can be used to comprehensively address energy justice concerns by different stakeholder groups and at all life cycle stages associated with a low-carbon energy system. Indicators for a social life cycle assessment framework that addresses energy justice are introduced and discussed. These indicators are organized by four categories of stakeholders for electrical energy systems: workers, electricity consumers, local communities, and society as a whole. The social life cycle assessment framework allows for variations in justice and equity to be determined not only at the generation stage, but through multiple points in the life cycle of the same energy system, from raw material extraction, through manufacturing, transportation, distribution, electricity generation, and waste management. This framework can address potential energy justice issues along the life cycle of new energy systems and assist in their design and planning for optimizing their social sustainability without overlooking vulnerable populations.

Due to growing interest in wind energy harvesting offshore as well as in the urban environment, vertical axis wind turbines (VAWTs) have recently received renewed interest. Their omni-directional capability makes them a very interesting option for use with the frequently varying wind directions typically encountered in the built environment while their scalability and low installation costs make them highly suitable for offshore wind farms. However, they require further performance optimization to become competitive with horizontal axis wind turbines (HAWTs) as they currently have a lower power coefficient (CP). This can be attributed both to the complexity of the flow around VAWTs and the significantly smaller amount of research they have received. The pitch angle is a potential parameter to enhance the performance of VAWTs. The current study investigates the variations in loads and moments on the turbine as well as the experienced angle of attack, shed vorticity and boundary layer events (leading edge and trailing edge separation, laminar-to-turbulent transition) as a function of pitch angle using Computational Fluid Dynamics (CFD) calculations. Pitch angles of −7° to +3° are investigated using Unsteady Reynolds-Averaged Navier-Stokes (URANS) calculations while turbulence is modeled with the 4-equation transition SST model. The results show that a 6.6% increase in CP can be achieved using a pitch angle of −2° at a tip speed ratio of 4. Additionally, it is found that a change in pitch angle shifts instantaneous loads and moments between upwind and downwind halves of the turbine. The shift in instantaneous moment during the revolution for various pitch angles suggests that dynamic pitching might be a very promising approach for further performance optimization.