Pulse power tests on nickel oxide electrodes for nickel—zinc electric vehicle batteries

In the development of non-sintered nickel oxide electrodes for NiZn electric vehicle (EV) batteries, maintaining adequate power performance was of particular concern. In the systems studied, the power output was limited by the nickel oxide electrodes. Simple pulse power tests were useful in characterizing the power performance in such cells. Although the cell impedance was not a simple resistance, the effective impedance at the end of a high rate discharge pulse had a resistive nature. This simplified the test procedures so that an accurate estimate of peak power could be obtained from one measurement. Measurements of the dependence on state of charge showed that the power output at 50% depth of discharge was representative of the power capability available during discharge.A method was devised to project power performance expected in a NiZn cell from NiCd cell tests. This was useful in testing the durabili     

Should policy-makers allocate funding to vehicle electrification or end-use energy efficiency as a strategy for climate change mitigation and energy reductions? Rethinking electric utilities efficiency programs

In order to reduce greenhouse gas emissions in the United States by an order of magnitude, a portfolio of mitigation strategies is needed. Currently, many utilities pursue energy efficiency programs. We study a case where utilities could choose whether to allocate their energy efficiency budget to either end-use efficiency or vehicle electrification as a means to reduce CO₂ emissions. We build a decision space that displays the conditions under which utilities should pursue either strategy. To build such decision space, assumptions are needed on how consumers respond to electric vehicle incentives, and what would be the baseline vehicle selected by consumers if no incentives were in place. Since these two aspects are highly uncertain, we treat them parametrically: if consumers are replacing a conventional vehicle with a PHEV, utility incentive programs to induce PHEV adoption appear to be cost-effective for a wide range of efficiency program costs and grid emissions factors.     

A simplified equivalent circuit model for simulation of Pb–acid batteries at load for energy storage application

Three main types of battery chemistries in consideration for vehicle applications are Pb–acid, nickel–metal hydride, and lithium-ion batteries. Lead–acid batteries are widely used in traditional automotive applications for many years. Higher voltage, high-rate discharge capability, good specific energy, lower temperature performance, lower thermal management requirement, and low-cost in both manufacturing and recycling are the advantages of the rechargeable battery. Disadvantages of the lead–acid battery are: weight concerns of lead metal (lower energy density and lower power density) and limited cycle-life (especially in deep-cycle duties). If two major disadvantages have been significantly changed to a proper state to compete with other battery chemistries, the Pb–acid battery is still a good candidate in considering of cost/performance ratio. The lead–acid battery is always a good power source for fast starting of cold vehicles, for recharging from either a stop-start braking system, or for a charge from the engine itself, which consumes battery energy or stores electricity back into chemical energy. The main reasons for reexamining this battery chemistry are cost-savings and life-cycling considerations upon advances in electrode structure design and enhancement of capacitance behavior inside the battery pack. Several Pb–acid batteries were evaluated and tested through a unique method, i.e., the electrochemical impedance method at different loads, in order to characterize and further understand the improved electrode processes and mechanisms in performance enhancement. The impedance data at loads were collected from these lead–acid batteries at load for further analysis. Battery electrode behaviors are evaluated through impedance data simulation using a proper equivalent circuit model. A defective battery and a failed Pb–acid battery were used in non-destructive analysis. The recent Pb–acid battery advancement in structures and designs and its potential application are also discussed for power reserve in energy-efficient vehicles and sustainable electricity storage.     

High-rate,valve-regulated lead–acid batteries — suitable for hybrid electric vehicles?

The possibility of replacing, with electric drive systems, at least some of the internal-combustion engines currently employed in road vehicles is being actively pursued by all the world's major automobile manufacturing companies. Minimum on-road emissions would be achieved by the adoption of pure electric vehicles, but the somewhat limited range available between charges of the batteries has led to a serious evaluation of hybrid electric vehicles as an acceptable compromise. In hybrids, a small internal-combustion engine, operated at high efficiency, will consume less fuel and produce less emissions than would a regular internal-combustion engine, and will allow considerable range extension over the pure electric vehicle. Eventually, an electric system which employs a fuel cell may become affordable. It is likely that all three systems — the pure electric, the hybrid electric, and the fuel cell system — will require battery support, particularly to provide boost power for acceleration and hill climbing. Although more expensive battery systems are being vigorously developed in pursuit of greater range per charge, the benchmark against which these systems are compared remains the valve-regulated lead–acid (VRLA) battery.     

Does human capital matter for energy consumption in China?

This article investigates the dynamic relationship between human capital and energy consumption using Chinese provincial data over the period 1990–2010. Considering for cross-sectional dependence and parameter heterogeneity across space and over time, we identify a significant and negative human capital–energy consumption relationship in China. Specifically, we find that a 1% increase in human capital reduces energy consumption by a range between 0.18% and 0.45%. Furthermore, this negative relationship can be attributed to stronger accumulation of post-school human capital in eastern China. This finding suggests that energy conservation in China could be achieved by improving post-school human-capital components such as on-the-job training, experience and learning-by-doing.     

Assessment of hydrogen as a potential energy storage for urban areas’ PV-assisted energy systems - Case study

The world is experiencing unprecedented development in the clean energy sector in residential and industrial applications. This paper provides a case study assessing different scenarios of greenizing the electrical energy demand in El-Mostakbal city in Egypt. Three scenarios are studied with consideration of a photovoltaic (PV) system integrated with the grid-connected city with different integrated system configurations. The scenarios for the grid-connected city are scenario-I: only PV, scenario-II: PV with batteries for electricity storage along with grid electricity, and scenario-III: PV with hydrogen production, storage, and utilization for covering the electric demand along with grid electricity, these scenarios are assessed technoeconomically, and the results show an optimized case where the electricity demand of the city can be met with 64.3% produced from solar energy, at $71.7 M of the net present cost.     

Does increasing energy or electricity consumption improve quality of life in industrial nations?

Among the world's nations, per capita energy and electricity consumption is highly correlated with diverse indicators of quality of life. This is often interpreted to mean that additional energy and electricity consumption causes improvements in life quality. Prior analyses of cross-sectional data question this interpretation for industrial nations that already have high per capita energy consumption. The present analysis with longitudinal data shows that among industrial nations, increases in per capita energy and electricity consumption over the past three decades are not associated with corresponding improvements in quality of life.     

Does financial development lower energy intensity?

The growth-induced effects of financial development have been well-established in the empirical literature, as well as the significance of financial development to energy demand behavior. However, the empirical evidence on the relationship between financial development and energy intensity remains sparse in the literature. Given the multifaceted nature of the effects of financial development, the proposed relationship seems a complex one and warrants an empirical investigation. Using the case of Ghana, this study provides an empirical answer to the question: does financial development lower energy intensity? To provide solid grounds for either rejection or acceptance of the null hypothesis, this study performed several robustness checks. Generally, the evidence revealed that financial development lowers energy intensity. Further, the results revealed that the price of energy, trade liberalization and industry structure play significant roles. These results have important implications for the design of macro energy efficiency policies and the creation of a ‘Green Bank’.     

Study and design of a hybrid wind–diesel-compressed air energy storage system for remote areas

Remote areas around the world predominantly rely on diesel-powered generators for their electricity supply, a relatively expensive and inefficient technology that is responsible for the emission of 1.2 million tons of greenhouse gas (GHG) annually, only in Canada [1]. Wind–diesel hybrid systems (WDS) with various penetration rates have been experimented to reduce diesel consumption of the generators. After having experimented wind–diesel hybrid systems (WDS) that used various penetration rates, we turned our focus to that the re-engineering of existing diesel power plants can be achieved most efficiently, in terms of cost and diesel consumption, through the introduction of high penetration wind systems combined with compressed air energy storage (CAES). This article compares the available technical alternatives to supercharge the diesel that was used in this high penetration wind–diesel system with compressed air storage (WDCAS), in order to identify the one that optimizes its cost and performances. The technical characteristics and performances of the best candidate technology are subsequently assessed at different working regimes in order to evaluate the varying effects on the system. Finally, a specific WDCAS system with diesel engine downsizing is explored. This proposed design, that requires the repowering of existing facilities, leads to heightened diesel power output, increased engine lifetime and efficiency and to the reduction of fuel consumption and GHG emissions, in addition to savings on maintenance and replacement cost.     

Hierarchical nanostructured Au–SnO2 for enhanced energy storage performance

Electrode materials with high energy and power density are mostly essential to overcome traditional fossil fuel use. Herein, we demonstrate the synthesis of Au decorated self-assembled SnO₂ nanoflowers consisting of nanorods by a cost-effective and eco-friendly solvothermal process. The as-synthesized SnO₂ based materials were employed as electrode material in the energy storage system, which delivered considerably high specific capacitance of 634.3 F/g at a current density of 1 A/g. The electrode material also exhibits excellent cycle stability of 83.52% after 4000 galvanostatic charge–discharge (GCD) cycles. The high specific capacitive value is attributed to the hybrid performance of battery and supercapacitor, more active sites, and higher surface area. A solid state asymmetry device was fabricated using Au–SnO₂ and activated carbon (AC) as positive and negative electrodes. The asymmetry device shows an excellent energy density of 168.9 Wh/kg at a power density of 1 kW/kg with an applied current density of 1 A/g.     

Does energy efficiency save energy? The debate and its consequences

This paper considers the debate in the UK and the USA on some economists' claims that improving energy efficiency will lead to a greater energy consumption (than would have otherwise occurred), a concept termed the Khazzoom–Brookes postulate. It analyses the criticisms of this claim and of the responses, particularly of the concept of ‘dematerialization’. The paper attempts to tackle the paucity of empirical evidence in the UK by looking at long-term trends in efficiency and use with respect to UK public lighting. Finally, it focuses on the views of two economists, namely Len Brookes and William Rees, who both accept the postulate but have differing views and policies on measures to reduce carbon emissions from fossil fuels. Brookes believes in free-market solutions, whereas Rees puts forward a vision of a sustainable future based on ecological tax-reform and reafforestation.     

Are energy statistics useful for making energy scenarios?

One can measure “energy quantities” – e.g. joules, BTU, quads – but only at a given scale and within a specific narrative about energy conversions at the time. Therefore, at the moment of generating aggregate indicators, the arithmetic summing of assessments of energy quantities referring to different scales and narratives is meaningless. This paper addresses epistemological problems typical of energy accounting, which are at the moment tackled by acknowledging the existence of unspecified “qualitative differences” among different energy forms – e.g. a joule of electricity has more “value” than a joule of coal. Three energy forms referring to different scales and narratives about energy conversions are relevant for national accounting: Primary Energy Sources (PES), Energy Carriers (EC), and End Uses (EU). We critically examine the usefulness of current energy statistics in relation to this distinction. The conventional linear representation – flow chart – based on a single scale and a single quantitative accounting confuses the three semantic categories and entails an important loss of information. Finally, we illustrate an innovative scheme for energy accounting across hierarchical levels that: (i) addresses the autocatalytic nature of energy transformations; (ii) provides a multi-scale quantitative representation; and (iii) preserves the semantic distinction between relevant energy forms (PES, EC, and EU).     

Does electricity price matter for innovation in renewable energy technologies in China?

Though the development of renewable energy is rapid, innovation in renewable energy technologies is relatively weak due to the late commencement of renewable energy in China. In addition, renewable energy is mainly introduced into the supply mix of electricity generation, which increases the costs of electricity generation. Higher electricity price will make renewable energy more competitive and call forth renewable energy technological innovation. Based on FMOLS and DOLS models, as well as PMG model, this paper investigates the induced long and short run effects of electricity price, funding support, and economic growth on innovation in renewable energy technologies at the provincial level in China during the period 2006–2016. The Conclusions drawn were: (1) R&D expenditure and economic growth have positive impacts on innovation in renewable energy technologies in the long and short run; (2) Electricity price only has a long run effect on patenting in renewable energy technologies; (3) In the long run, a 1% increase in electricity price can lead to a 0.7825%–1.0952% increase in the patent counts of renewable energy technologies; (4) Electricity pricing system in China does not play any role in driving renewable energy technological innovation in the short run.     

The German energy audit program for firms—a cost-effective way to improve energy efficiency?

In 2008, a program was established in Germany to provide grants for energy audits in small- and medium-sized enterprises. It aims to overcome barriers to energy efficiency, like the lack of information or a lack of capacity, and is intended to increase the adoption of energy efficiency measures. We evaluate the program's impact in terms of energy savings, CO₂ mitigation, and cost-effectiveness. We find that firms adopt 1.7?C2.9 energy efficiency measures, which they would not have adopted without the program. Taking a firm's perspective, the program shows a net present value ranging from ?0.4 to 6??/MWh saved, which very likely implies a net benefit. For the government, each ton of CO₂ mitigated costs between 1.8 and 4.1??. Each euro of public expenditure on audit grants led to 17?C33?? of private investment. The cost-effectiveness of the program for firms and the low share of public expenditure underline its value for the German energy efficiency policy mix and suggest that it should be expanded in Germany. Further, the good experiences with the program in Germany should encourage countries which have not yet established an audit program to do so.     

Does renewable energy substitute LNG international trade in the energy transition?

Renewable energy is a vital tool for the energy transition and sustainable development goals. The global economy, however, remains heavily reliant on fossil fuels despite efforts to reduce global greenhouse gas emissions. Demand for natural gas is rising as a bridge for moving towards a low-carbon economy, but whether natural gas and renewable energy represent substitutes in the global energy mix remains underexplored. We tackle this concern by examining the impact of renewable policies on international trade in liquified natural gas (LNG) among 1359 trading partners during the period 1988–2017. We measure renewable energy policies based on the ratio of renewable energy to total energy usage in importing trading partners, which also corresponds to a proxy for energy transition policies. The analysis is conducted using a global panel dataset in a trade gravity framework by applying various econometric methods and model specifications to measure LNG trade as a dependent variable. The results show that the energy transition, measured by the share of renewable energy, has a negative impact on LNG trade. This suggests that investing in cleaner energy technologies can reduce LNG trade globally, as a channel towards reducing natural gas demand. The results are consistent with the narrative where natural gas and renewable energy represent partial substitutes at the global level. However, subgroup analysis suggests that less-developed economies and the shale revolution period seem to impede progress towards the energy transition.     

Polyurethanes as solid–solid phase change materials for thermal energy storage

Polyurethane polymers (PUs) have been synthesized as solid–solid phase change materials for thermal energy storage using three different kinds of diisocyanate molecules and polyethylene glycols (PEGs) at three different molecular weights. PEGs and their derivatives are usually used as phase change units in polymeric solid–solid phase change materials due to the hydroxyl functional groups. 1000, 6000, and 10,000 g/mol number average molecular weight PEGs are used as working element as hexamethylene, isophorone, and toluene diisocyanates are used as hard segment at the backbone. The effects of molecular weight of PEG and type of diisocyanate on the thermal energy storage properties have been discussed. Only two of the produced polymers show solid–liquid phase change as the rest show solid–solid phase transitions. The produced PUs with a solid–solid phase transitions have potential to be used in thermal energy storage systems.     

Who does what in China’s new energy vehicle industry?

This paper provides an overview of the Chinese new energy vehicle industry and discusses the role of state in the industry’s development. Chinese policies have aimed to promote the development of new energy technologies and to reduce the consumer price of new energy vehicles. Chinese authorities have also been concerned about the balance between collaboration and competition in the sector, since most key actors are owned by the state. One solution has been the establishment of a number of industry alliances linking auto enterprises, universities and research institutes, to promote both collaboration (within each alliance) and competition (between alliances).     

Is inexpensive natural gas hindering the grid energy storage industry?

Grid energy storage is a maturing technology and forecasts of the industry's growth have been promising. However, recent years have realized little growth in actual deployments of grid-level storage and several high-profile storage companies and projects have failed. We hypothesize that falling natural gas prices have significantly reduced the potential profit from many U.S. energy storage projects since 2009 and quantify that effect. We use engineering–economic models to calculate the monthly revenue to energy storage devices providing frequency regulation and energy arbitrage in several electricity markets and compare that revenue to prevailing natural gas prices. We find that flywheel devices providing frequency regulation were profitable in months when natural gas prices were above $7/mcf, but face difficulties at current prices (around $4/mcf). For energy arbitrage alone, we find that the breakeven capital cost for large-scale storage was around $300/kWh in several key locations in 2004–2008, but is around $100/kWh in the same locations today. Though cost and performance improvements have been continually decreasing the effective cost of energy services from storage, fundamental market signals indicating the need for energy storage are at or near 10-year lows for both energy arbitrage and frequency regulation.     

Hybrid electric vehicles and electrochemical storage systems — a technology push–pull couple

In the advance of fuel cell electric vehicles (EV), hybrid electric vehicles (HEV) can contribute to reduced emissions and energy consumption of personal cars as a short term solution. Trade-offs reveal better emission control for series hybrid vehicles, while parallel hybrid vehicles with different drive trains may significantly reduce fuel consumption as well. At present, costs and marketing considerations favor parallel hybrid vehicles making use of small, high power batteries. With ultra high power density cells in development, exceeding 1 kW/kg, high power batteries can be provided by adapting a technology closely related to consumer cell production. Energy consumption and emissions may benefit from regenerative braking and smoothing of the internal combustion engine (ICE) response as well, with limited additional battery weight. High power supercapacitors may assist the achievement of this goal. Problems to be solved in practice comprise battery management to assure equilibration of individual cell state-of-charge for long battery life without maintenance, and efficient strategies for low energy consumption.     

Feedback on household electricity consumption: a tool for saving energy?

Improved feedback on electricity consumption may provide a tool for customers to better control their consumption and ultimately save energy. This paper asks which kind of feedback is most successful. For this purpose, a psychological model is presented that illustrates how and why feedback works. Relevant features of feedback are identified that may determine its effectiveness: frequency, duration, content, breakdown, medium and way of presentation, comparisons, and combination with other instruments. The paper continues with an analysis of international experience in order to find empirical evidence for which kinds of feedback work best. In spite of considerable data restraints and research gaps, there is some indication that the most successful feedback combines the following features: it is given frequently and over a long time, provides an appliance-specific breakdown, is presented in a clear and appealing way, and uses computerized and interactive tools.