Electricity Consumption Efficiency Research Articles

Energy and Environmental Impacts of Potential Application of Fully or Partially Electric Propulsion Vehicles: Application to Lisbon and São Miguel, Portugal

The transportation sector has been one of the fastest growing sectors resulting in a high final energy consumption in Portugal (40% in 2011), with road transportation sector being responsible for 82% of that energy consumption. As a result, alternative vehicle technologies such as electric vehicles are becoming increasingly important since they may contribute to greater energy efficiency. However, their electric autonomy limitations influence the mobility paradigm, making their acceptance dependent on the location and context of driving. Thus, the objective of this study was to characterize mobility patterns and compare the potential application of fully or partially electric propulsion vehicles in two different Portuguese contexts: the Lisbon region (city pattern) and the Island of São Miguel, Azores, Portugal (rural pattern). This characterization was performed by on road monitoring of 9 drivers in Lisbon and 17 drivers in Sao Miguel. São Miguel drivers are those which have a more suitable pattern for using alternative vehicles comparably to the Lisbon region, since they travel about 47% less than the Lisbon population (33 km daily compared to 62 km per day) and, consequently, having a charging time availability about 30% higher. The São Miguel population also has greater presence in lower vehicle specific power (VSP) modes, with an average speed 25% lower than the Lisbon population. São Miguel drivers present greater efficiency in electricity consumption per kilometer (25% more efficient) than the Lisbon sample. Finally, the impacts of using alternative vehicles were quantified, concluding that the alternative technologies would reduce the Well-to-Wheel (WTW) energy consumption per kilometer between 37% and 68%.

Life cycle assessment of caustic soda production: a case study in China

Abstract Life cycle assessment was conducted to estimate the environmental impact of caustic soda production. Electricity and raw salt production accounted for >90% of the overall environmental burden. These findings can be attributed to electrical consumption for bipolar electrolysis and brine extraction, diesel consumption for generating electricity during well production, and direct heavy metal emissions during drilling fluid loss and waste disposal. The key factors in reducing the overall environmental impact include optimizing raw salt production, electricity, and steam consumption efficiency, choosing drilling fluids with less toxic heavy metals (e.g., arsenic, barium, molybdenum, selenium, vanadium, beryllium, and nickel), minimizing brine leakage during brine transport, reducing the volume of drilling fluid lost, and decreasing the transport distance from brine buyers to suppliers.

The dynamics of sectoral electricity demand for a panel of US states: New evidence on the consumption–growth nexus

In this paper, we use a panel of the 48 contiguous US states over the period 1970–2009 to examine the dynamics of electricity demand in addressing the four hypotheses set forth in the literature: growth, conservation, neutrality, and feedback. In doing so we provide both short-run and long-run elasticity estimates for electricity demand. Recent developments in nonstationary panel estimation techniques allow for heterogeneity in the coefficients while examining the direction of causality among electricity consumption, electricity prices, and income growth. In addition to the full sample, we also disaggregate the sample into three sectors: commercial, industrial, and residential. The short-run results provide evidence in favor of the growth hypothesis for the aggregate sample, as well as for the industrial sector. For the residential and commercial sectors, the conservation hypothesis is supported. Long-run results favor the conservation hypothesis. To ascertain differences in electricity demand relating to electricity intensity we also examine states based on their efficiency in electricity consumption. Overall, the results yield in favor of the growth hypothesis for low intensity states and conservation hypothesis for high intensity states.

A mechanistic study of arsenate removal from artificially contaminated clay soils by electrokinetic remediation

Batch desorption experiments and bench-scale electrokinetic experiments were performed to elucidate the electrokinetic remediation mechanisms of arsenate from artificially contaminated kaolinite. The electrokinetic experiments in which a constant voltage was applied demonstrated that high soil pH favored arsenate remediation with respect to both the remediation time and electricity consumption. It was also demonstrated that applying a pulse voltage (1h ON, 1h OFF) significantly improved the electricity consumption efficiency when the soil pH was maintained at the initial value during the experiments; this trend was not observed when the soil pH was gradually increased from the cathode side. These electrokinetic experimental results, with the support of arsenate desorption data obtained from batch experiments, indicate that the remediation rate-limiting step varied with soil pH. When the soil pH was maintained at the initial value of 7.2 during the experiments, arsenate desorption was the remediation rate-limiting step rather than the migration of dissolved arsenate toward the anode. Conversely, when the cathode pH was not controlled and the soil pH was correspondingly increased gradually from the cathode side, the migration of hydroxyl and desorbed arsenate ions toward the anode played a more important role in the control of the overall remediation efficiency.

스마트 그리드를 위한 소규모 전력에너지 관리 시스템 개발에 관한 연구

스마트 그리드는 기존에 발전소에서 전력을 일방적으로 공급하는 단방향 전력망에 정보기술을 접목하여 전력 공급자와 소비자가 양방향으로 실시간 정보를 교환함으로써 에너지 효율을 최적화하는 방식이다. 스마트그리드의 전력 관리 시스템은 동적인 가격제도와 함께 소비자들에게 전력사용에 대한 정보를 제공함으로써, 수요의 반응을 유도하고, 전력 계통의 투자와 운영에 있어 효율을 향상시키는데 있다. 하지만, 최근 전력 관리 시스템들은 실시간 가격 등 가격 제도에 주로 초점을 두고 있다. 본 논문에서는 가격 제도에 초점을 둔 기존 전력관리 시스템을 개선하여 전력 사용의 효율성에 초점을 둔 전력에너지 운영 관리 시스템을 제안한다. 전력 데이터는 배전반에 설치된 PMU(Phasor Measurement Units)를 통해 수집되며 데이터 마이닝 기법을 통한 분석 방법으로 효율성 높이고자 한다. 또한 전력 부족 및 과잉 공급 시 PMU와 양방향 통신을 통해 제어할 수 있도록 구현 및 실험하여 전력에너지 관리시스템의 효율성을 입증하였다. A smart grid is an electric-power grid that employs a new information technology.This technology makes it possible to exchange real-time energy information between suppliers and consumers, finally resulting in high energy efficiency. The energy management system in smart grid provides up to date information on electricity consumption as well as dynamic electricity price to consumers of smart grid system. However, the existing energy management systems only focus on pricing system, for example, real-time electricity prices. In this paper, we try to improve the existing energy management system and propose the energy management system that mainly focuses on the efficiency of electricity consumption. In the proposed management system, PMU(Phasor Measurement Units) installed in switchboards gathers electricity data in a real time. We also propose to use data mining method, which is applied to analyzed electricity data for improving energy efficiency. Also, the proposed energy management system is designed to efficiently control the electricity between PMU and management system in case of a shortage of electricity or surplus electricity.

Elimination of pharmaceutical residues in biologically pre-treated hospital wastewater using advanced UV irradiation technology: A comparative assessment

UV irradiation technology as a membrane bioreactor (MBR) post-treatment was investigated and assessed. Both UV low pressure (LP) and medium pressure (MP) lamps were examined. The technology was installed in a pilot plant treating hospital wastewater to provide the study with adequate field data.The effect of the UV irradiation was enhanced with varying dosages of H2O2 to establish an advanced oxidation process (AOP). The efficiency of the pharmaceutical removal process was assessed by examining 14 micropollutants (antibiotics, analgesics, anticonvulsants, beta-blockers, cytostatics and X-ray contrast media) which are typically released by hospitals and detected with liquid chromatography coupled tandem mass spectrometry (LC–MS/MS).While the MBR treatment generally showed only a low degradation capacity for persistent pharmaceuticals, much better degradation was obtained by applying UV irradiation and H2O2 as AOP. The “conventional” cost-benefit analysis of the different technology options taking into account both electrical energy consumption and pharmaceutical removal efficiency, revealed clearly better performance of low pressure UV lamps as AOP. However, a holistic comparison between the different scenarios was carried out by evaluating their environmental impacts using the life cycle assessment (LCA) methodology. Decisive advantages were highlighted to include this approach in the decision making process.

Environmental and economic life cycle assessment of aluminum-silicon alloys production: a case study in China

A coupled life cycle costing and life cycle assessment was carried out to estimate the economic and environmental impact of silicon-aluminum alloy production. The results showed that the aluminum alloy made from secondary aluminum accounted for 70%–95% of the environmental benefits in most categories, except in the land occupation and economic categories, compared with the aluminum alloy made from primary aluminum. These findings could be attributed to the decrease in energy and raw material consumption (i.e., electricity, sodium hydroxide, petroleum coke, and charcoal consumption) and the relatively high cost of secondary aluminum scrap. Optimizing raw material and electricity consumption efficiency, decreasing the transport distance from raw material (e.g., bauxite and old aluminum scrap) buyers to suppliers, and changing the end-life treatment of red mud from landfill to road building material production are key factors in reducing the overall environmental and economic impact.

Environmental assessment of recycled printing and writing paper: A case study in China

A life cycle assessment was conducted using IMPACT2002+ to estimate the environmental impact of producing printing and writing paper, which is entirely made with wastepaper. To confirm and add credibility to the study, uncertainty analysis was conducted using Taylor series expansion. Printing and writing paper produced from wood pulp was assessed for comparison. Compared with the wood pulp contained scenario, printing and writing paper made from wastepaper represented environmental benefit on non-carcinogens, respiratory inorganics, global warming, and non-renewable energy categories. In both scenarios, the technologies significantly contribute to the potential impacts of non-carcinogens, respiratory inorganics, terrestrial ecotoxicity, global warming, and non-renewable energy. The influence of the technologies on the way other categories affect the environment was negligible. Improved efficiency in electricity consumption, decreased transport distance from raw material buyers to suppliers, and change in the end-life treatment of solid waste from landfill to incineration are the key factors in reducing the overall environmental impact.

Curtain color and lighting program in broiler production: I - general performance

The objective of the present study was to evaluate mortality and performance, darkling beetle population (Alphitobius diaperinus), light intensity, electrical energy consumption and economic efficiency of broilers reared under two lighting programs (nearly continuous or intermittent) and two curtain colors (yellow or blue). The experiment was conducted between June, 2004 and May, 2005. Six flocks were sequentially housed in four 12 × 10 m broiler houses divided into 4 pens with 200 birds each. Litter was reused six times or until flock 6. Body weight and feed conversion were determined on days 21, 35, and 42 of each flock. Mortality was recorded daily. Electrical energy consumption was recorded at the end of the grow-out of each flock (every 42 days). A completely randomized design in a 6 × 2 × 2 factorial arrangement (flocks, lighting programs, curtains) with four replicates per treatment was applied. Broilers reared in houses with yellow curtains and under nearly continuous lighting programs presented the best feed conversion ratio and the highest body weight. Nearly continuous lighting programs resulted in 1.48 times more sudden deaths and 1.34 times higher general mortality when compared with intermittent lighting programs. Electrical energy consumption was 2.12 times higher in nearly continuous lighting programs in relation to intermittent lighting programs. The presence of darkling beetles was higher in broiler houses with blue curtains and intermittent lighting program. The economic analysis showed the feasibility of using a mixed system, with intermittent light program in winter and spring and nearly continuous lighting program in the summer and autumn, both in broiler houses with yellow curtains.

On the controversial effect of sodium sulphate as supporting electrolyte on electrocoagulation process: A review

One of the important factors for electrocoagulation (EC) process is the conductivity of the solution to be treated. Essential mechanisms in EC are charge neutralisation by metal (Fe/Al) hydroxocations and aggregation by van der Waals forces since fl occulation of pollutants with metal is caused by their adsorption on metal hydroxide aggregates. In order to enhance the EC process efficiency in organic wastewater effluents, sodium sulphate (Na2 SO4) has been used as a supporting electrolyte (SE) to increase the electric current diffusion in the EC cell. However, literature has reported controversial effect of sodium sulphate on EC process. This review tries to understand the sulphate effect on the EC reactions. Na2SO4 has been found less efficient than NaCl as SE in EC process for the removal of humic substances, oil-in-water emulsions, and fluoride. However, for unskimmed milk sample and cutting oil emulsion sulphate anions were found to be quite harmful both for electrical consumption and EC efficiency. T...

TFP Electricity Consumption Efficiency and Influencing Factor Analysis Based on DEA Method

Total Factor Productivity (TFP) electricity consumption efficiency was calculated in this article based on Data Envelopment Analysis (DEA) method by panel data of 4 districts from 2001 to 2007, and related influencing factors were econometrically tested to explain the difference of electricity consumption efficiency of different districts.

The role of energy efficiency spending in Maryland’s implementation of the Regional Greenhouse Gas Initiative

What are the economic consequences of increased state spending on electricity consumption efficiency? The State of Maryland faces this question in deciding how much of its CO 2 allowances auction proceeds (under the Regional Greenhouse Gas Initiative) to devote to such programs. Starting at a base of 25% of the proceeds, we consider the energy savings, emissions reductions, employment, and other impacts of increasing that percentage to 50% and 100%. A series of models – Haiku, JHU-OUTEC, and IMPLAN – are used for the analysis. We conclude that increasing the state’s expenditures on energy efficiency programs would result in a decline in electricity consumption in the state and a corresponding decline in expenditures on electricity. Program implementation would lead to net positive growth in statewide economic activity and include growth in both jobs and wages.

An environmental evaluation of household garbage processors

AbstractThe amount of garbage emitted from households and industries has been constantly increasing in recent years, and its treatment cost has been a financial burden to municipal governments in Japan. Many municipal governments recommend that their citizens purchase household garbage processors in order to reduce the volume of garbage transferred to and incinerated at their facilities. Actually, 1535 municipal governments subsidize their citizens' purchase of electrical garbage processors and/or compost containers. These subsidies should be assessed from various points of view, such as the costs and benefits to municipal governments and citizens, and also global or local environmental loads. An environmental planning department of a city office sent questionnaires to its residents to investigate the utilization of the subsidized devices. An environmental organization of citizens supported the department with design of the questionnaire form and analysis of the collected questionnaire data. In this paper, the processes of designing the form and analyzing the data are explained, and then an evaluation of the subsidy is presented. The conclusions are as follows: Electrical garbage processors would be beneficial for dealing with local environmental problems such as lack of a final landfill site. However, the processors will increase CO2 emissions unless their electrical consumption efficiency can be improved. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(7): 42–52, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10285

On the crucial influence of some supporting electrolytes during electrocoagulation in the presence of aluminum electrodes

The influence of some supporting electrolytes on aluminum electrode oxidation and pH variation during electrocoagulation of an unskimmed milk sample and a cutting oil emulsion has been investigated. Among the electrolytes studied, sulfate anions were found to be quite harmful both for electrical consumption and electrocoagulation efficiency. At the opposite, chloride and ammonium ions were particularly benefic respectively for aluminum corrosion and pH regulation, whereas sodium cations were observed to have a neutral role. The results indicate that electrocoagulation can be realized at low anodic potential even in the presence of sulfate ions when the [Cl(-)]/[SO(4)(2-)] ratio is around or greater than 1/10. The detrimental effect of sulfates on electrocoagulation efficiency can be thwarted by the use of the ammonium salt thanks to its related buffer effect.

家庭用生ごみ処理機の環境負荷評価

The amount of garbage emitted from households and industries has been constantly increasing in recent years, and its treatment cost has been a financial burden to municipal governments in Japan. Many municipal governments recommend that their citizens purchase household garbage processors in order to reduce the volume of garbage transferred to and incinerated at their facilities. Actually, 1535 municipal governments subsidize their citizens' purchase of electrical garbage processors and/or compost containers. These subsidies should be assessed from various points of view, such as the costs and benefits to municipal governments and citizens, and also global or local environmental loads. An environmental planning department of a city office sent questionnaires to its residents to investigate the utilization of the subsidized devices. An environmental organization of citizens supported the department with design of the questionnaire form and analysis of the collected questionnaire data. In this paper, the processes of designing the form and analyzing the data are explained, and then an evaluation of the subsidy is presented. The conclusions are as follows: Electrical garbage processors would be beneficial for dealing with local environmental problems such as lack of a final landfill site. However, the processors will increase CO2 emissions unless their electrical consumption efficiency can be improved. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(7): 42–52, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10285

Indian Urban Building Sector: CDM Potential through Energy Efficiency in Electricity Consumption

Indian economic growth is likely to lead to a huge increase of energy use in buildings but so far, policies to address this issue are lacking. Standard building energy use concerning glazing, air conditioning and lighting in different climatic zones across India leads to energy use per m2 which is 3-4 times of the German average. We assess the potential to improve building energy efficiency and how measures in the building sector could be framed as projects under the Clean Development Mechanism. CDM case studies for large buildings in the Indian public and private sector are presented. They achieve annual greenhouse gas reductions of 500 to 10,000 ton, which may not be sufficient to overcome the CDM transaction cost barrier. Despite short payback periods, the high initial investment and lack of integrated building management makes these projects additional. Large-scale appliance dissemination programs for air-conditioners and Compact Fluorescent Lamps (CFLs) may offer interesting opportunities if the monitoring challenge can be overcome.

Interlighting improves production of year-round cucumber

Three cucumber stands ( Cucumis sativus L. cv. Cumuli) were grown in southern Finland to investigate the effects of two supplemental lighting regimes on yield and efficiency of electricity consumption in lighting for year-round production. The lighting regimes examined included top lighting (TL), where all of the lamps were mounted above the canopy and top + interlighting (T + IL) which comprised 75% of top lamps and 25% of the lamps mounted vertically 1.3 m above the ground between the single plant rows. The artificial photosynthetic photon flux (PPF) near the plant rows, the air temperature and vapour pressure deficit (VPD) in the canopy were noted to be slightly higher in T + IL than in TL. The total (natural + artificial) PPF inside the greenhouse during cultivation of the winter, spring and summer stands were 19.4, 29.5 and 38.6 mol m −2 day −1 in TL and 20.4, 31.5 and 41.2 mol m −2 day −1 in T + IL, respectively. Top + interlighting was shown to enhance cucumber productivity; T + IL increased the annual total and first class fruit weight and number, fruit size and percentage of first class fruit. A total annual increase of 20% in first class fruit weight was achieved through a 6% increase in electricity consumption for lighting purposes. The first class fruit weights in winter, spring and summer stands were 32.0, 42.1 and 30.8 kg m −2 in TL and 38.2, 55.4 and 32.1 kg m −2 in T + IL, respectively. The efficiency of electricity consumption for lighting was better for the whole year in T + IL than in TL (120 g versus 108 g first class fruit weight kWh -1). Efficiency varied between stands; T + IL proved more efficient than TL during the winter and spring seasons, whereas TL was more efficient in summer.

Investigation of Thunder™ Actuators as Underwater Propulsors

Piezoelectric actuators have been used for active vibration control, noise suppression, health monitoring, etc. The large appeal in using smart material actuators stems from their high mechanical energy density. A relatively new actuator Thin Layer Composite Unimorph Ferroelectric Driver and Sensor (THUNDER) has overcome the displacement hurdles that have plagued traditional piezoelectric based actuators. It is capable of providing a displacement of the order of 0.5 cm. This allows the actuator to be used in some underwater applications, such as propulsion. To date the electrical power consumption and electro-mechanical efficiency of these actuators has not been quantified; specifically, applied as underwater propulsors. Some of the challenges in obtaining this information stems from the actuator’s nontraditional actuating architecture, high voltage requirements, and its electrical nonlinearity. This work experimentally determines the mechanical displacement and the electrical power consumption of the THUNDER actuators used as underwater propulsors. An estimate of a lower bound of the thrust that can be generated by the clamshell actuator is obtained. It is found that the actuator has a peak flow rate of approximately 1500 cm3/s and can generate a peak thrust greater than approximately 4.5 N. This preliminary analysis neglected the pressure forces acting on the actuator and therefore, the actual thrust is not computed. It is found that the average electrical power consumed by two THUNDER actuators placed in a clamshell configuration operating at 14 Hz is approximately 8 W, which is significantly less than that consumed by other autonomous underwater vehicles. The displacement response and the current draw of the actuators are determined to be nonlinear. The result of this work indicates that the use of THUNDER actuators has great potential to create an underwater propulsor that has low power consumption, can operate at great depths, and eliminates the need for seals, bearings and a propeller.

Electro-Osmotic Dewatering under Intermittent Power Application by Rectification of A.C. Electric Field.

A continuous DC electric field has been generally used for fundamental study and practical application of electro-osmotic dewatering. Under DC conditions, however, the electrical contact resistance between the electrode and the dewatered material is excessively increased in the dewatering process, resulting in interruption of the dewatering process. For efficient performance of electroosmotic dewatering, intermittent power application was used to reduce such excessive increase of the electrical contact resistance with the lapse of time. An intermittent electric field was made by rectifying an AC electric field, and it was constituted of half waves. Both rectangular and sine waves were used as the wave form of an AC electric field. Electro-osmotic dewatering under the rectified half-wave intermittent electric field was investigated experimentally, under both conditions of the same peak-value voltage and the same effective-value (r.m.s.-value) voltage as the voltage applied under DC and AC electric fields.Intermittent power application is suggested to reduce the increase of the electrical contact resistance with time caused by the DC process. In the case of intermittent power application having the same effective voltage as DC and AC, the rate and the amount of removed water were increased compared with DC and AC fields, and the efficiency of electric power consumption for the amount of removed water was much higher than them.

Keepin and Kats — a comment

We consider the arguments of Keepin and Kats that nuclear power and conservation are mutually exclusive methods of reducing CO 2 emissions from coal-fired electric power generation. In contrast to their approach, we suggest that a combination of nuclear power and conservation can reduce CO 2. Nuclear power is appropriate and economic in some regions. The gradual introduction of equipment and techniques for improving the efficiency of electricity consumption will continue to be made and they will eventually reduce growth in electricity demand. Introducing about 600 GW of nuclear power in 35 years and efficiency improvements that reduce growth in world electricity demand by two-thirds (to an average of 1.5% per year) would hold CO 2 emissions from electric power production to levels similar to today's.