• Energy Research
• 11. Sustainability close

the 1960s, transportation industry planners have sought an energy-efficient design for a train that can glide through air at speeds up to 500 kilometers per hour. This type of train, called a magnetically levitated (maglev) train, is thought to be a viable solution to meet the nation's growing need for intercity and urban transportation networks. However, despite some promising developments, unresolved concerns with the operation and safety of maglev trains has prevented the transition from demonstration model to commercial development. Inductrack, a maglev system originally conceived by Livermore physicist Richard Post, is designed to address these issues. Post's work on Inductrack began with funding from Livermore's Laboratory Directed Research and Development Program, and in 2003, the technology was licensed to General Atomics (GA) in San Diego for train and transit system applications. This year, members of the Livermore-GA team received an R&D 100 Award for Inductrack's development. Inductrack uses permanent magnets to produce the magnetic fields that levitate the train and provides economic and operational advantages over other maglev systems. It can be adapted to both high-speed and urban-speed environments. In the event of a power failure, the train slows gradually until it comes to rest on its auxiliary wheels.more » The maintenance requirements for Inductrack are also lower than they are for other systems, plus it has a short turning radius and is designed for quiet operation. Previous designs for maglev systems did not offer the energy efficiency or safety protections that are in the Inductrack design. Electromagnetic systems (EMS) use powered electromagnets to levitate the train. However, these systems are based on magnetic attraction rather than repulsion and thus are inherently unstable. In EMS trains, the levitation gap--the separation between the magnet pole faces and the iron rail--is only about 10 millimeters and, during operation, must be maintained to within {+-}1 millimeter. Position sensors and electronic feedback systems are required to control the magnetic current and to compensate for the inherent instability. This requirement, plus the onboard source of emergency power required to ensure operational safety during a sudden power loss, increases the complexity of EMS trains. In contrast, in electrodynamic systems (EDS), large superconducting magnet coils mounted on the sides of the train generate high-intensity magnetic field poles. Interaction of the current between the coils and the track levitates the train. At operating speeds (above a liftoff speed of about 100 kilometers per hour), the magnetic levitation force balances the weight of the car at a stable position. EDS trains do not require the feedback control systems that EMS trains use to stabilize levitation. However, the superconducting magnetic coils must be kept at temperatures of only 5 kelvins, so costly electrically powered cryogenic equipment is required. Also, passengers, especially those with pacemakers, must be shielded from the high magnetic fields generated by the superconductors.« less

Energy consumption for year-round cooling of Internet Data Centres (IDCs) is growing rapidly. In this study, an integrated air-cooled chiller, by adopting magnetic-bearing centrifugal compressor and sharing heat exchangers, is proposed to supply chilled water for IDCs. The integrated chiller can automatically work in three modes (vapour compression, mechanically driven heat pipe, and thermosyphon) according to ambient temperature. To analyze energy performance and feasibility of the chiller, an hourly energy consumption model is developed. Then, the energy performance of the integrated chiller located in four typical cities in north China (Harbin, Shenyang, Beijing, and Jinan) are investigated. Additionally, an economic analysis is also carried out. The results show that the energy saving effect is significant, especially in colder regions, and the proposed chiller is economically feasible.

The MagneMotion Maglev system, called M3, is an alternative to all conventional guided transportation systems. Advantages include major reductions in capital cost, travel time, operating cost, noise, and energy consumption. Vans or small-bus size vehicles operating automatically with headways of only a few seconds can be moved in platoons to achieve capacities of at least 12,000 passengers per hour per direction. Small vehicles lead to lighter guideways, shorter waiting time for passengers, lower power requirements for wayside inverters, more effective regenerative braking, and reduced station size. The design objectives were achieved by taking advantage of high-energy permanent magnets, improved microprocessor-based power electronics, precise position sensing, lightweight vehicles, a guideway matched to the vehicles, and the ability to use sophisticated computer-aided design tools for analysis, simulation, and optimization. Arrays of permanent magnets on both sides of a vehicle provide suspension, guidance, and a field for linear synchronous motor propulsion. Feedback-controlled current in control coils wound around the magnets stabilizes the suspension. The motor windings are integrated into suspension rails and excited by inverters along the guide-way. M3 is designed to provide speeds up to 45 m/s (101 mph) and acceleration and braking up to 2 m/s2 (4.5 mph/s) without onboard propulsion equipment. Operating speeds and accelerations can be modified by changing only the power system and wayside inverters. Capital cost, travel time, and operating cost are predicted to be less than half that of any competing transit system.

Two of the most widely emphasized contenders for carbon emissions reduction in the electricity sector are nuclear power and renewable energy. While scenarios regularly question the potential impacts of adoption of various technology mixes in the future, it is less clear which technology has been associated with greater historical emission reductions. Here, we use multiple regression analyses on global datasets of national carbon emissions and renewable and nuclear electricity production across 123 countries over 25 years to examine systematically patterns in how countries variously using nuclear power and renewables contrastingly show higher or lower carbon emissions. We find that larger-scale national nuclear attachments do not tend to associate with significantly lower carbon emissions while renewables do. We also find a negative association between the scales of national nuclear and renewables attachments. This suggests nuclear and renewables attachments tend to crowd each other out.

First of all, overall economic growth objectives in China are concisely and succinctly specified in this report. Secondly, this report presents a forecast of energy supply and demand for China`s economic growth for 2000--2050. In comparison with the capability of energy construction in China in the future, a gap between supply and demand is one of the important factors hindering the sustainable development of Chain`s economy. The electric power industry is one of China`s most important industries. To adopt energy efficiency through high technology and utilizing energy adequately is an important technological policy for the development of China`s electric power industry in the future. After briefly describing the achievements of China`s electric power industry, this report defines the target areas and policies for the development of hydroelectricity and nuclear electricity in the 2000s in China, presents the strategic position of China`s electric power industry as well as objectives and relevant plans of development for 2000--2050. This report finds that with the discovery of superconducting electricity, the discovery of new high-temperature superconducting (HTS) materials, and progress in materials techniques, the 21st century will be an era of superconductivity. Applications of superconductivity in the energy field, such as superconducting storage, superconducting transmission, superconducting transformers, superconducting motors, its application in Magneto-Hydro-Dynamics (MHD), as well as in nuclear fusion, has unique advantages. Its market prospects are quite promising. 12 figs.

Renewable energy technologies, necessary for low-carbon infrastructure networks, are being adopted to help reduce fossil fuel dependence and meet carbon mitigation targets. The evolution of these technologies has progressed based on the enhancement of technology-specific performance criteria, without explicitly considering the wider system (global) impacts. This paper presents a methodology for simultaneously assessing local (technology) and global (infrastructure) performance, allowing key technological interventions to be evaluated with respect to their effect on the vulnerability of wider infrastructure systems. We use exposure of low carbon infrastructure to critical material supply disruption (criticality) to demonstrate the methodology. A series of local performance changes are analyzed; and by extension of this approach, a method for assessing the combined criticality of multiple materials for one specific technology is proposed. Via a case study of wind turbines at both the material (magnets) and technology (turbine generators) levels, we demonstrate that analysis of a given intervention at different levels can lead to differing conclusions regarding the effect on vulnerability. Infrastructure design decisions should take a systemic approach; without these multilevel considerations, strategic goals aimed to help meet low-carbon targets, that is, through long-term infrastructure transitions, could be significantly jeopardized.

Low-carbon energy transitions aim to stay within a carbon budget that limits potential climate change to 2 °C - or well below - through a substantial growth in renewable energy sources alongside improved energy efficiency and carbon capture and storage. Current scenarios tend to overlook their low net energy returns compared to the existing fossil fuel infrastructure. Correcting from gross to net energy, we show that a low-carbon transition would probably lead to a 24-31% decline in net energy per capita by 2050, which implies a strong reversal of the recent rising trends of 0.5% per annum. Unless vast end-use efficiency savings can be achieved in the coming decades, current lifestyles might be impaired. To maintain the present net energy returns, solar and wind renewable power sources should grow two to three times faster than in other proposals. We suggest a new indicator, 'energy return on carbon', to assist in maximizing the net energy from the remaining carbon budget.

Low-carbon investments are necessary for driving the energy system transformation that is called for by both the Paris Agreement and Sustainable Development Goals. Improving understanding of the scale and nature of these investments under diverging technology and policy futures is therefore of great importance to decision makers. Here, using six global modelling frameworks, we show that the pronounced reallocation of the investment portfolio required to transform the energy system will not be initiated by the current suite of countries’ Nationally Determined Contributions. Charting a course toward ‘well below 2 °C’ instead sees low-carbon investments overtaking fossil investments globally by around 2025 or before and growing thereafter. Pursuing the 1.5 °C target demands a marked upscaling in low-carbon capital beyond that of a 2 °C-consistent future. Actions consistent with an energy transformation would increase the costs of achieving the goals of energy access and food security, but reduce the costs of achieving air-quality goals.