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Bioenergy is currently regarded as a renewable energy source with a high growth potential. Forest-based biodiesel, with the significant advantage of not competing with grain production on cultivated land, has been considered as a promising substitute for diesel fuel by many countries, including China. Consequently, extracting biodiesel from <em>Jatropha</em><em> curcas</em> has become a growing industry. However, many key issues related to the development of this industry are still not fully resolved and the prospects for this industry are complicated. The aim of this paper is to evaluate the net energy, CO₂ emission, and cost efficiency of <em>Jatropha</em> biodiesel as a substitute fuel in China to help resolve some of the key issues by studying data from this region of China that is well suited to growing <em>Jatropha</em>. Our results show that: (1) <em>Jatropha</em> biodiesel is preferable for global warming mitigation over diesel fuel in terms of the carbon sink during <em>Jatropha</em> tree growth. (2) The net energy yield of <em>Jatropha</em> biodiesel is much lower than that of fossil fuel, induced by the high energy consumption during <em>Jatropha</em> plantation establishment and the conversion from seed oil to diesel fuel step. Therefore, the energy efficiencies of the production of <em>Jatropha</em> and its conversion to biodiesel need to be improved. (3) Due to current low profit and high risk in the study area, farmers have little incentive to continue or increase <em>Jatropha</em> production. (4) It is necessary to provide more subsidies and preferential policies for <em>Jatropha</em> plantations if this industry is to grow. It is also necessary for local government to set realistic objectives and make rational plans to choose proper sites for <em>Jatropha</em> biodiesel development and the work reported here should assist that effort. Future research focused on breading high-yield varieties, development of efficient field management systems, and detailed studies lifecycle environmental impacts analysis is required to promote biologically and economically sustainable development of <em>Jatropha</em> biodiesel and to assist government agencies in setting realistic objectives and appropriate and advantageous policies for the regions and the country.

PHEVs and BEVs make use of battery cells optimized for high energy rather than for high power. This means that the power abilities of these batteries are limited. In order to enhance their performance, a hybrid Rechargeable Energy Storage System (RESS) architecture can be used combining batteries with electrical-double layer capacitors (EDLCs). Such a hybridized architecture can be accomplished using passive or active systems. In this paper, the characteristics of these topologies have been analyzed and compared based on a newly developed hybridization simulation tool for association of lithium-ion batteries and EDLCs. The analysis shows that the beneficial impact of the EDLCs brings about enhanced battery performances in terms of energy efficiency and voltage drops, rather than extension of vehicle range. These issues have been particularly studied for the passive and active hybrid topologies. The classical passive and active topologies being expensive and less beneficial in term of cost, volume and weight, a new hybrid configuration based on the parallel combination of lithium-ion and EDLCs on cell level has been proposed in this article. This topology allows reducing cost, volume, and weight and system complexity in a significant way. Furthermore, a number of experimental setups have illustrated the power of the novel topology in terms of battery capacity increase and power capabilities during charging and discharging. Finally, a unique cycle life test campaign demonstrated that the lifetime of highly optimized lithium-ion batteries can be extended up to 30%&#8211;40%.

SiO₂ hollow spheres and low relative permittivity insulation paper handsheets composed of these SiO₂ hollow spheres with different weight percentages were successfully prepared. Low-content SiO₂ hollow spheres were uniformly dispersed in the insulation paper handsheets. The relative permittivity of the immersed oil Kraft-SiO₂ hollow sphere handsheets (K-SiO₂) initially decreased and then increased with increased amount of SiO₂ hollow spheres. K-5% SiO₂ possessed the lowest relative permittivity of approximately 1.68 at 50 Hz. The breakdown voltage of the paper-oil-paper composite insulation system increased from 26.4 kV to 30.5 kV with decreased relative permittivity of the paper from 2.55 to 1.68. The relationship between the relative permittivity and electric field strength of typical samples were also calculated.

The imbalance between energy resource availability, demand, and production capacity, coupled with inherent economic and environmental uncertainties make strategic energy resources planning, management, and decision-making a challenging process. In this paper, a descriptive approach has been taken to synthesize the world’s energy portfolio and the global energy balance outlook in order to provide insights into the role of Organization of Petroleum Exporting Countries (OPEC) in maintaining “stability” and “balance” of the world’s energy market. This synthesis illustrates that in the absence of stringent policies, <em>i.e</em>., if historical trends of the global energy production and consumption hold into the future, it is unlikely that non-conventional liquid fuels and renewable energy sources will play a dominant role in meeting global energy demand by 2030. This should be a source of major global concern as the world may be unprepared for an ultimate shift to other energy sources when the imminent peak oil production is reached. OPEC’s potential to impact the supply and price of oil could enable this organization to act as a facilitator or a barrier for energy transition policies, and to play a key role in the global energy security through cooperative or non-cooperative strategies. It is argued that, as the global energy portfolio becomes more balanced in the long run, OPEC may change its typical high oil price strategies to drive the market prices to lower equilibria, making alternative energy sources less competitive. Alternatively, OPEC can contribute to a cooperative portfolio management approach to help mitigate the gradually emerging energy crisis and global warming, facilitating a less turbulent energy transition path while there is time.

Sequestration of carbon dioxide (CO₂) in the form of its hydrates in natural methane (CH₄) hydrate reservoirs, via CO₂/CH₄ exchange, is an attractive pathway that also yields valuable CH₄ gas as product. In this paper, we describe a macroscale experiment to form CO₂ and CH₄-CO₂ hydrates, under seafloor-mimic conditions, in a vessel fitted with glass windows that provides visualization of hydrates throughout formation and dissociation processes. Time resolved pressure and temperature data as well as images of hydrates are presented. Quantitative gas conversions with pure CO₂, calculated from gas chromatographic measurements yielded values that range from 23 – 59% that correspond to the extent of formed hydrates. In CH₄-rich CH₄-CO₂ mixed gas systems, CH₄ hydrates were found to form preferentially.