Results in Journal BMC Energy: 15
(searched for: journal_id:(4241701))
BMC Energy, Volume 2, pp 1-16; doi:10.1186/s42500-020-00015-2
The concept of “committed emissions” allows us to understand what proportion of the Paris-constrained and rapidly diminishing global carbon dioxide (CO2) budget is potentially taken up by existing infrastructure. Here, this concept is applied to international shipping, where long-lived assets increase the likelihood for high levels of committed emissions. To date, committed emissions studies have focussed predominantly on the power sector, or on global analyses in which shipping is a small element, with assumptions of asset lifetimes extrapolated from other transport modes. This study analyses new CO2, ship age and scrappage datasets covering the 11,000 ships included in the European Union’s new emissions monitoring scheme (EU MRV), to deliver original insights on the speed at which new and existing shipping infrastructure must be decarbonised. These results, using ship-specific assumptions on asset lifetimes, show higher committed emissions for shipping than previous estimates based on asset lifetimes similar to the road transport sector. The estimated baseline committed emissions value is equivalent to 85–212% of the carbon budget for 1.5 °C that is available for these EU MRV ships, with the central case exceeding the available carbon budget. The sector does, however, have significant potential to reduce this committed emissions figure without premature scrappage through a combination of slow speeds, operational and technical efficiency measures, and the timely retrofitting of ships to use zero-carbon fuels. Here, it is shown that if mitigation measures are applied comprehensively through strong and rapid policy implementation in the 2020s, and if zero-carbon ships are deployed rapidly from 2030, it is still possible for the ships in the EU MRV system to stay within 1.5 °C carbon budgets. Alongside this, as there are wide variations between and within ship types, this new analysis sheds light on opportunities for decision-makers to tailor policy interventions to deliver more effective CO2 mitigation. Delays to appropriately stringent policy implementation would mean additional measures, such as premature scrappage or curbing the growth in shipping tonne-km, become necessary to meet the Paris climate goals.
BMC Energy, Volume 2, pp 1-10; doi:10.1186/s42500-020-00014-3
A mixed ionic and semiconducting composite in a single-layer configuration has been shown to work as a fuel cell at a lower temperature (500–600 °C) than a traditional solid-oxide fuel cell. The performance of a single-layer fuel cell (SLFC) is often limited by high resistive losses. Here, a eutectic mixture of alkali-carbonates was added to SLFC to improve the ionic conductivity. The dual-phase composite ionic conductor consisted of a ternary carbonate (sodium lithium potassium carbonate, NLKC) mixed with gadolinium-doped cerium oxide (GDC). Lithium nickel zinc oxide (LNZ) was used as the semiconducting material. The LNZ-GDC-NLKC SLFC reached a high power density, 582 mW/cm2 (conductivity 0.22 S/cm) at 600 °C, which is 30 times better than without the carbonate. The best results were obtained with the ternary carbonate which decreased the ohmic losses of the cell by more than 95%, whereas the SLFC with a binary carbonate (sodium lithium carbonate, NLC) showed a lower conductivity and performance (243 mW/cm2, 0.17 S/cm at 600 °C). It is concluded that adding carbonates to LNZ-GDC will improve the ionic conductivity and positively contribute to the cell performance. These results suggest a potential path for further development of SLFCs, but also imply the need for efforts on up-scaling and stability to produce practical applications with SLFC.
BMC Energy, Volume 2, pp 1-13; doi:10.1186/s42500-020-00013-4
Emerging literature highlights the essential role played by decarbonised electricity generation in future energy systems consistent with the Paris Climate Agreement. This analysis compares the impacts of high levels of renewable electricity and negative emissions technologies on exploratory visions of the future EU power system (2050) in terms of emissions reduction, technical operation and total system costs. The analysis shows that high renewable power system scenarios coupled with low levels of negative emissions technologies, such as biomass carbon capture and storage (< 2% of installed capacity), can deliver a net-negative European power system at lower comparable cost without breaching published sustainable biomass potentials in Europe (or requiring imports) or geological storage potentials while also contributing to power system inertia. Direct air capture has the capability to further decrease overall carbon emissions. While carbon capture and storage and power-to-gas must overcome market, regulatory and social acceptance challenges, given their potential benefits to emissions reduction, costs and system operation their role in a future power system should be further explored.
BMC Energy, Volume 2, pp 1-13; doi:10.1186/s42500-020-00012-5
Biomass-derived 5-ethoxymethylfurfural (EMF) with excellent energy density and satisfactory combustion performance holds great promise to meet the growing demands for transportation fuels and fuel additives to a certain extent. In this review, we summarized the relative merits of the EMF preparation from different feedstocks, such as platform chemicals, biomass sugars and lignocellulosic biomass. Advances for EMF synthesis over homogeneous (i.e. inorganic acids and soluble metal salts), heterogeneous catalysts (i.e. zeolites, heteropolyacid-based hybrids, sulfonic acid-functionalized catalysts, and others) or mixed-acid catalysts were performed as well. Additionally, the emerging development for the EMF production was also evaluated in terms of the different solvents system (i.e. single-phase solvents, biphasic solvents, ionic liquids, and deep eutectic solvents). It is concluded with current challenges and prospects for advanced biofuel EMF preparation in the future.
BMC Energy, Volume 2, pp 1-9; doi:10.1186/s42500-020-0011-8
Enzymes play indispensable roles in producing biofuels, a sustainable and renewable source of transportation fuels. Lacking rational design rules, the development of industrially relevant enzyme catalysts relies heavily on high-throughput screening. However, few universal methods exist to rapidly characterize large-scale enzyme libraries. Therefore, assay development is necessary on an ad hoc basis to link enzyme properties to spectrophotometric signals and often requires the use of surrogate, optically active substrates. On the other hand, mass spectrometry (MS) performs label-free enzyme assays that utilize native substrates and is therefore generally applicable. But the analytical speed of MS is considered rate limiting, mainly due to the use of time-consuming chromatographic separation in traditional MS analysis. Thanks to new instrumentation and sample preparation methods, direct analyte introduction into a mass spectrometer without a prior chromatographic step can be achieved by laser, microfluidics, and acoustics, so that each sample can be analyzed within seconds. Here we review recent advances in MS platforms that improve the throughput of enzyme library screening and discuss how these advances can potentially facilitate biofuel research by providing high sensitivity, selectivity and quantitation that are difficult to obtain using traditional assays. We also highlight the limitations of current MS assays in studying biofuel-related enzymes and propose possible solutions.
BMC Energy, Volume 1, pp 1-7; doi:10.1186/s42500-019-0010-9
This communication elucidates the charge storage mechanism of a TiO2 electrode in 1 mol dm− 3 AlCl3 for use in aqueous-ion batteries. Cyclic voltammetry studies suggest a surface contribution to charge storage and that cycle life can be improved by limiting the potential ≥ − 1.0 V vs SCE. In order to enhance this surface contribution, a simple vacuum impregnation technique was employed to improve electrode-electrolyte contact. This resulted in a significant improvement in the high rate performance of TiO2, where a capacity of 15 mA h g− 1 was maintained at the very high specific current of 40 A g− 1, a decrease of only 25% from when the electrode was cycled at 1 A g− 1. The vacuum impregnation process was also applied to copper-hexacyanoferrate, envisaged as a possible positive electrode, again resulting in significant improvements to high-rate performance. This demonstrates the potential for using this simple technique for improving electrode performance in other aqueous electrolyte battery systems.
BMC Energy, Volume 1, pp 1-17; doi:10.1186/s42500-019-0009-2
In this work we explore the ramifications of incoming changes brought by the energy transition, most notably the increased penetration of variable renewable energy (VRE) and phase-out of nuclear and other conventional electricity sources. The power grid will require additional flexibility capabilities to accommodate such changes, as the mismatch between generation and demand is bound to increase. Through mathematical modeling and optimization, we simulate the German power grid and investigate the requirements of on-grid large-scale storage. Different scenarios are evaluated up to 2050, when 80% of the gross electricity consumption is planned to be provided by renewable energy. Dispatchable power plants will play a key role in the transition to an energy mix with high shares of VRE. Around 120 GW of additional large-scale storage are required until 2050. Between the electrochemical technologies evaluated, lithium-ion was the best candidate. A strong reliance on dispatchables was observed, in case the commissioning of VRE plants goes slower than planned. Energy curtailment increases with VRE shares, with up to 14 TWh curtailed in high VRE scenarios in 2050.
BMC Energy, Volume 1, pp 1-23; doi:10.1186/s42500-019-0008-3
Since the last two decades, microgrid, as one typical structure in smart grid framework, has been receiving increasing attention in the world. Meanwhile, fuel cell (FC), as one promising power source, has redrawn the attention of both academia and industry since the beginning of 21th century. Some encouraging achievements in FC technology have been realized thanks to the efforts taken in the last years. Due to this, it is seen that FC, as a clean and efficient energy source, is penetrating into different fields. Among the applications, integrating FCs into microgrids has shown interesting advantages on improving the performance of microgrids and promoting the use of the hydrogen energy. Some ongoing projects have shown that FCs of different power scales can be integrated into microgrids smartly and in different manners. Along with the advantages carried by the combination of the two technologies, many challenges lying on multiple domains are faced in the process. The challenges can be from the FC, the microgrid, and the integration of these two technologies. In this review paper, the advantages of integrating FCs into microgrids are summarized after recalling the knowledge background of FC. The challenges and ongoing researches on FCs and FCs based microgrids are then reviewed. Based on the analysis, the research directions are then extracted in view of the challenges.
BMC Energy, Volume 1; doi:10.1186/s42500-019-0006-5
BMC Energy, Volume 1; doi:10.1186/s42500-019-0007-4