Search

Abstract: This paper shows the determination of typical load profiles (TLPs) by using Fuzzy C-Means (FCM) clustering and Probability Neural Network (PNN) classification method. Load profiles provide useful information on electricity consumption to both consumers and suppliers. Precise knowledge on consumer''s electricity consumption becomes essential for the suppliers to design tariffs, load balancing, load planning, etc. As for consumers, such knowledge is important for them to keep track of their electricity consumption and to enable them to take part in retail market especially for those who do not have appropriate metering equipment. Hence, an effective, fast and cheap method to obtain load profile has to be developed. Objectives of this paper are to obtain groups of TLPs by using FCM clustering and to assign TLPs using PNN algorithm. One of the main issues in FCM clustering is the determination of optimal number of cluster. This paper proposes optimal number of cluster determination by using Davies-Bouldin index. PNN network is trained to directly allocate the TLPs to the representative groups of consumers. The data used in this project are obtained from Tenaga Nasional Berhad (TNB). [Copyright &y& Elsevier]

Highlights • Parameters of 60 electricity-saving measures and 16 abatement measures are compiled. • Synergies of electricity use in China's chemical sector at grid level are assessed. • Efficient use of power can cut 154 Mt CO 2eq , 295 kt SO 2 , 322 kt NO x and 64 kt PM 2.5. • North and Northwest grids have the largest economic benefits on emissions reduction. • Grid with high electricity price is more sensitive to price change than other grids. Abstract Industry is a large electricity user. China's chemical industry (globally the largest based on sales) contributes 7% to China's GDP, while it consumes 11% of the total electricity consumption in industry and is responsible for 40% of total CO 2eq , 40% of SO 2 , 59% of NO x and 18% of PM-emissions of the chemical industry emissions. The heterogeneity of GHG and air pollutant emissions across electricity grids (within a country) is rarely included in analyses. In this paper, electricity conservation supply curves are developed (distinguishing the grids) to estimate the cost-effective and technical potentials of electricity conservation in China's chemical industry. The emission factors per grid for GHG (i.e. CO 2 , CH 4 and N 2 O) and air pollutants (i.e. SO 2 , NO x and PM 2.5) are calculated and used to quantify the emissions mitigation achieved by electricity saving technologies in the chemical industry for the period 2012–2035. Results show that significant multiple benefits can be obtained by implementing electricity efficiency measures. There are large differences among the six grids in terms electricity savings and emissions abatement of GHG and air pollutants. 83% of the total electricity saving potential is contributed by the North, Northwest and Central grids, equal to 32% of baseline electricity consumption in 2035. In 2035, 129 Mt of CO 2 , 33 kt CO 2eq of CH 4 , 571 kt CO 2eq of N 2 O, 235 kt of SO 2 , 275 kt of NO x and 52 kt of PM 2.5 in these three grids can be avoided as a result of electricity savings (a reduction of 31–33% compared to baseline emissions). When decision-makers set targets for energy saving and emission reduction, the multiple benefits and grid heterogeneity should not be ignored. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a study on energy performance of Singapore''s hotel buildings. Energy consumption data and other pertinent information were collected from 29 quality hotels through a national survey. Building features and operational characteristics contributing to the variations in hotel energy performance were discussed. The annual average total energy use intensity (EUI) in these hotels is 427kWh/m2. Electricity and gas are used in all sampled hotels, and some hotels also use diesel to power standby generator or hot water boiler. We also investigated relationships between electricity consumption and number of occupied rooms in individual hotels; the weak correlations found indicate it is necessary to improve energy management when occupancy rate is low. Besides, Pearson correlations between hotel energy use intensity and possible explanatory indicators revealed that three-star hotels differ from high class establishments in energy use. Worker density and years after the last major energy retrofit were also found to be highly correlated to hotel building energy use intensity. Also discussed in this paper is the effect of weather conditions on electricity consumption of the hotels. [Copyright &y& Elsevier]

Distributed energy resources present opportunities to serve grid and customer need through two-way power flow. New values, methods, and planning are required to efficiently interconnect and utilize DERs. This paper analyzes New York’s and California’s DER proceedings to provide a comparison of the similarities and differences between these and other states that will result in different levels of deployments and valuations of DERs. [ABSTRACT FROM AUTHOR]

Electric and hydrogen vehicles can help decarbonize heavy duty vehicles (HDV). Few studies examine how to meet energy requirements of decarbonized HDVs, and all assume electricity will come from centralized systems. However, decarbonized HDVs could significantly increase energy demands in areas with limited transmission access, potentially favoring deployment of distributed energy resources (DERs). In this paper, we develop an optimization-based techno-economic model that minimizes costs of meeting HDV energy demands by optimizing investments in and operations of DERs, investments in transmission interconnections, and wholesale electricity purchases. We apply it to a modeled U.S. dataset of electric HDV charging demands to quantify the deployment and value potential of three DERs — solar, batteries, and nuclear small modular reactors (SMRs) in the year 2040. For fleets of 100% electric HDVs to 60% electric and 40% hydrogen HDVs, DERs are deployed at 78% to 95% of all charging stations and meet between 24% to 30% of total HDV energy demand. Investments in DERs reduce annual costs by $647 million to $1.9 billion across all stations, while individual stations can save $20 million to over $100 million annually. SMRs make up over 99% of total deployed DER capacity, indicating significant potential for SMR deployment in this emerging market. Widespread DER deployment is robust to capital cost uncertainty in SMRs and transmission lines, wholesale electricity prices, and other factors. [Display omitted] • We create a model to quantify the value of distributed energy resources for meeting decarbonized heavy duty vehicle energy demand. • Distributed energy resources are deployed at 78% to 95% of all charging stations. • Annual cost savings from distributed energy resources investments can be as high as $1.9 billion nation-wide, and $104 million at an individual station. • Small modular microreactors supply approximately between 24% and 30% of heavy duty vehicle energy demand annually. [ABSTRACT FROM AUTHOR]

Abstract: A modern supermarket energy control system has a concurrent need for electricity, space heating or cooling, and food refrigeration. The power supply to the supermarket is primarily from the national grid, where losses in efficiency are due to the processes of energy conversion and transmission. Combined heat and power (CHP) offers the potential to locally produce electrical power and heating which could save energy and reduce CO2 emissions in the long run. During the summer months, as the space heating requirement in a supermarket is relatively small, the energy efficiency of a CHP installation can be improved by using excess thermal energy to drive a sorption refrigeration system to provide space cooling or refrigeration. This process is also known as tri-generation. In recent years, the use of CO2 as a refrigerant in supermarkets has received considerable attention due to its negligible contribution to direct greenhouse gas emissions and excellent thermophysical and heat transfer properties. Consequently, the application of a tri-generation system in a supermarket with CO2 refrigeration merits further investigation. In this paper, to evaluate the performance of a tri-generation system in the supermarket, a previously tested 80kWe microturbine device was applied into an operational supermarket to generate power and provide space heating and cooling through exhaust heat. The performance evaluation and comparison for this tri-generation application is based on the prediction from an integrated model of supermarket energy control, cascade CO2 refrigeration and tri-generation systems. The results from this simulation demonstrate the feasibility of a tri-generation system in the supermarket and pave the way for further consideration towards designs in future. [Copyright &y& Elsevier]

Abstract: An energy network with polygeneration system and CCS suitable for China was proposed in our previous work in consideration of low-cost CCS and energy providing safety. In this paper, based on life-cycle analysis, the role of the Energy Network has been investigated at the national level. Results show that with the import dependency of oil controlled in the range of 40%–60% during 2020 to 2030, up to 22% of the total capacity of coal fired supercritical power plants may be replaced by hundreds of new polygeneration plants for electricity and alternative fuels. When the oil import dependency will be kept from 40% to 60%, the Energy Network can save 20%–30% of energy and cut down 30%–40% of total costs every year compared to the present method with coal fired supercritical power plants and traditional alternative fuel plants with CO2 capture. And the Energy Network can capture more than 0.1 billion tons of CO2 with high concentration over 98% each year. Moreover, from the aspect of CCS, this Energy Network can realize as low as 15$/t of total CCS cost due to the quite low energy penalties of CO2 capture in the polygeneration systems and the combination of CO2 sources and storage sites. The new Energy Network has realized the proper combination of energy utilization and CO2 capture and storage according to the unique state of China. It is suitable for China and may play an important role in CCS in the future. [Copyright &y& Elsevier]

Abstract: The evaluation of building energy consumption usually requires building energy profiles on an hourly basis. Computer simulations can be used to obtain this information but generating simulations requires a significant amount of experience, time, and effort to enter detailed building parameters. This paper presents a simple methodology to estimate hourly electrical and fuel energy consumption of a building by applying a series of predetermined coefficients to the monthly energy consumption data from electrical and fuel utility bills. The advantage of having predetermined coefficients is that it relieves the user from the burden of performing a detailed dynamic simulation of the building. The coefficients provided to the user are obtained by running EnergyPlus Benchmark Models simulations; thus, the simulation process is transparent to the user. The methodology has been applied to a hypothetical building placed both in Atlanta, GA, and in Meridian, MS, and in both cases, errors obtained for the estimated hourly energy consumption are mainly within 10%. [ABSTRACT FROM AUTHOR]

This review deals with organic Rankine cycle powered by geothermal resource which is one favorable substitute for conventional fossil energy. Organic Rankine cycle power plants are suitable for utilization of low-temperature energy sources (low grade energy) such as geothermal resource having low temperature (below 150 ᵒC). The applications of organic Rankine cycle for electricity production from geothermal energy resource was reviewed first, where the choice of geothermal energy resources and organic fluids was discussed for different ORC configurations and operating conditions. Hybrid optimization approaches for the purpose of maintaining long term performance of enhanced geothermal system reservoirs were also summarized. Furthermore, an in-depth review of energy and exergy efficiencies of ORCs was conducted. Key factors that influence the energy and energy efficiencies of organic Rankine cycle were discussed in detail. Then, the economic indexes such as electricity production cost and levelized cost of electricity for different organic Rankine cycle configurations were compared with other conventional power generation systems to examine the commercialization of the Organic Rankine cycle. Finally, life cycle assessment that evaluates the whole life performance of geothermal organic Rankine cycle energy systems was reviewed. The Environmental impacts of geothermal ORC were also considered. Compared with other review papers on geothermal organic Rankine cycle s, the present review provides the latest materials for more systematically surveying the geothermal organic Rankine cycle, which will be a valuable source of guidance and directions for engineers and researchers in this field. [ABSTRACT FROM AUTHOR]