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Open AccessCommunication

A Novel Method for Fast Configuration of Energy Storage Capacity in Stand-Alone and Grid-Connected Wind Energy Systems

by Haixiang Zang, Mian Guo, Zeyu Qian, Zhinong Wei and Guoqiang Sun

Sustainability 2016, 8(12), 1336; https://0-doi-org.brum.beds.ac.uk/10.3390/su8121336 - 17 Dec 2016

Cited by 1 | Viewed by 3820

In this paper, a novel method is proposed and applied to quickly calculate the capacity of energy storage for stand-alone and grid-connected wind energy systems, according to the discrete Fourier transform theory. Based on practical wind resource data and power data, which are [...] Read more.

In this paper, a novel method is proposed and applied to quickly calculate the capacity of energy storage for stand-alone and grid-connected wind energy systems, according to the discrete Fourier transform theory. Based on practical wind resource data and power data, which are derived from the American Wind Energy Technology Center and HOMER software separately, the energy storage capacity of a stand-alone wind energy system is investigated and calculated. Moreover, by applying the practical wind power data from a wind farm in Fujian Province, the energy storage capacity for a grid-connected wind system is discussed in this paper. This method can also be applied to determine the storage capacity of a stand-alone solar energy system with practical photovoltaic power data. Full article

(This article belongs to the Special Issue Sustainable Energy Storage Applications for Renewable Generation Support)

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4195 KiB

Open AccessCommunication

For a Green Stadium: Economic Feasibility of Sustainable Renewable Electricity Generation at the Jeju World Cup Venue

by Eunil Park, Sang Jib Kwon and Angel P. Del Pobil

Sustainability 2016, 8(10), 969; https://0-doi-org.brum.beds.ac.uk/10.3390/su8100969 - 23 Sep 2016

Cited by 7 | Viewed by 6371

Abstract

After the 2002 FIFA World Cup in South Korea and Japan, the local governments of South Korea were left in charge of several large-scale soccer stadiums. Although these governments have made significant efforts toward creating profits from the stadiums, it is proving to [...] Read more.

After the 2002 FIFA World Cup in South Korea and Japan, the local governments of South Korea were left in charge of several large-scale soccer stadiums. Although these governments have made significant efforts toward creating profits from the stadiums, it is proving to be too difficult for several administrations to cover their full operational, maintenance, and conservation costs. In order to overcome this problem, one of the governments, Seogwipo City, which owns Jeju World Cup Stadium (JWCS), is attempting to provide an independent renewable electricity generation system for the operation of the stadium. The current study therefore examines potential configurations of an independent renewable electricity generation system for JWCS, using HOMER software. The simulation results yield three optimal system configurations with a renewable fraction of 1.00 and relatively low values for the cost of energy ($0.405, $0.546, and $0.692 per kWh). Through the examination of these three possible optimal configurations, the implications and limitations of the current study are presented. Full article

(This article belongs to the Special Issue Sustainable Energy Storage Applications for Renewable Generation Support)

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2665 KiB

Open AccessArticle

Numerical Analysis of the Factors Influencing a Vertical U-Tube Ground Heat Exchanger

by Shangyuan Chen, Jinfeng Mao, Xu Han, Chaofeng Li and Liyao Liu

Sustainability 2016, 8(9), 882; https://0-doi-org.brum.beds.ac.uk/10.3390/su8090882 - 01 Sep 2016

Cited by 7 | Viewed by 4074

Abstract

The development of a three-dimensional, unsteady state model, which couples heat transfer with groundwater seepage for a vertical U-tube ground heat exchanger (GHE) is presented. The influence of underground soil thermal properties, grout materials, inlet water temperature and velocity, and groundwater seepage on [...] Read more.

The development of a three-dimensional, unsteady state model, which couples heat transfer with groundwater seepage for a vertical U-tube ground heat exchanger (GHE) is presented. The influence of underground soil thermal properties, grout materials, inlet water temperature and velocity, and groundwater seepage on heat transfer in the GHE is examined. The results indicate that before the heat in the borehole is saturated, the heat flux in the GHE is directly proportional to the thermal conductivity coefficient of the grout materials. The radius of the thermal effect of the GHE and the recovery rate of the temperature in the soil are also proportional to the thermal diffusion coefficient of the soil. In cooling mode, the increase of the inlet water temperature of the GHE results in enhanced heat transfer. However, this may cause issues with heat buildup. The increase of the inlet water velocity in the GHE enhances heat convection in the tube. The effect of thermal-seepage coupling in groundwater can reduce the accumulated heat, thus resulting in the effective enhancement of the heat transfer in the GHE. Full article

(This article belongs to the Special Issue Sustainable Energy Storage Applications for Renewable Generation Support)

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4249 KiB

Open AccessArticle

Adaptive Curtailment Plan with Energy Storage for AC/DC Combined Distribution Systems

by Seungmin Jung, Yong-Tae Yoon and Gilsoo Jang

Sustainability 2016, 8(8), 818; https://0-doi-org.brum.beds.ac.uk/10.3390/su8080818 - 19 Aug 2016

Cited by 4 | Viewed by 5503

Abstract

For developing a large-scale combined system with a number of distributed resources, an appropriate compensation strategy based on the system components and changeable condition must be configured to handle the characteristics of the internal systems. Since renewable sources generate various fluctuations, the compensation [...] Read more.

For developing a large-scale combined system with a number of distributed resources, an appropriate compensation strategy based on the system components and changeable condition must be configured to handle the characteristics of the internal systems. Since renewable sources generate various fluctuations, the compensation plans for the storage device connected along with the sources should be supported by a precise expectation method. A cooperative strategy involving the sharing of the DC section with environmentally sensitive generators, like photovoltaic system (PVs) or waves, demands appropriate ESS compensation solutions, owing to its complexity. An active power-control algorithm with voltage-expectation based on the DC power flow is introduced in this paper and is applied in the designed case studies performed on the electromagnetic transient simulation. DC based multi-generation system is composed by applying tidal generator and super capacitor. To utilize wind energy, an offshore wind–wave generation system was utilized in the verification process. Full article

(This article belongs to the Special Issue Sustainable Energy Storage Applications for Renewable Generation Support)

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4936 KiB

Open AccessArticle

Intelligent Control of a Distributed Energy Generation System Based on Renewable Sources

by Ciprian Vlad, Marian Barbu and Ramon Vilanova

Sustainability 2016, 8(8), 748; https://0-doi-org.brum.beds.ac.uk/10.3390/su8080748 - 04 Aug 2016

Cited by 8 | Viewed by 4384

Abstract

The control of low power systems, which include renewable energy sources, a local network, an electrochemical storage subsystem and a grid connection, is inherently hierarchical. The lower level consists of the wind energy sources (power limitation at rated value in full load regime [...] Read more.

The control of low power systems, which include renewable energy sources, a local network, an electrochemical storage subsystem and a grid connection, is inherently hierarchical. The lower level consists of the wind energy sources (power limitation at rated value in full load regime and energy optimization in partial load regime) and photovoltaic (energy conversion optimization) control systems. The present paper deals with control problem at the higher level and aims at generating the control solution for the energetic transfer between the system components, given that the powers of the renewable energy sources and the power in the local network have random characteristics. For the higher level, the paper proposes a mixed performance criterion, which includes an energy sub-criterion concerning the costs of electricity supplied to local consumers, and a sub-criterion related to the lifetime of the battery. Three variants were defined for the control algorithm implemented by using fuzzy logic techniques, in order to control the energy transfer in the system. Particular attention was given to developing the models used for the simulation of the distributed energy system components and to the whole control system, given that the objective is not the real-time optimization of the criterion, but to establish by numerical simulation in the design stage the “proper” parameters of the control system. This is done by taking into account the multi-criteria performance objective when the power of renewable energy sources and the load have random characteristics. Full article

(This article belongs to the Special Issue Sustainable Energy Storage Applications for Renewable Generation Support)

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17781 KiB

Open AccessArticle

A High-Efficiency Voltage Equalization Scheme for Supercapacitor Energy Storage System in Renewable Generation Applications

by Liran Li, Zhiwu Huang, Heng Li and Honghai Lu

Sustainability 2016, 8(6), 548; https://0-doi-org.brum.beds.ac.uk/10.3390/su8060548 - 13 Jun 2016

Cited by 20 | Viewed by 8252

Abstract

Due to its fast charge and discharge rate, a supercapacitor-based energy storage system is especially suitable for power smoothing in renewable energy generation applications. Voltage equalization is essential for series-connected supercapacitors in an energy storage system, because it supports the system’s sustainability and [...] Read more.

Due to its fast charge and discharge rate, a supercapacitor-based energy storage system is especially suitable for power smoothing in renewable energy generation applications. Voltage equalization is essential for series-connected supercapacitors in an energy storage system, because it supports the system’s sustainability and maximizes the available cell energy. In this paper, we present a high-efficiency voltage equalization scheme for supercapacitor energy storage systems in renewable generation applications. We propose an improved isolated converter topology that uses a multi-winding transformer. An improved push-pull forward circuit is applied on the primary side of the transformer. A coupling inductor is added on the primary side to allow the switches to operate under the zero-voltage switching (ZVS) condition, which reduces switching losses. The diodes in the rectifier are replaced with metal-oxide-semiconductor field-effect transistors (MOSFETs) to reduce the power dissipation of the secondary side. In order to simplify the control, we designed a controllable rectifying circuit to achieve synchronous rectifying on the secondary side of the transformer. The experimental results verified the effectiveness of the proposed design. Full article

(This article belongs to the Special Issue Sustainable Energy Storage Applications for Renewable Generation Support)

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953 KiB

Open AccessArticle

Implications and Measurement of Energy Poverty across the European Union

by Alexandru Maxim, Costică Mihai, Constantin-Marius Apostoaie, Cristian Popescu, Costel Istrate and Ionel Bostan

Sustainability 2016, 8(5), 483; https://0-doi-org.brum.beds.ac.uk/10.3390/su8050483 - 16 May 2016

Cited by 70 | Viewed by 9534

Abstract

Energy poverty, or the inability of households to afford adequate access to energy services, is an issue that can have a significant effect on the quality of life and even the state of health of individuals and even the overall development of a [...] Read more.

Energy poverty, or the inability of households to afford adequate access to energy services, is an issue that can have a significant effect on the quality of life and even the state of health of individuals and even the overall development of a nation. Since it was first brought into focus more than two decades ago in the UK, this topic has gradually gained the attention of academics and policy makers all across the EU and beyond. The current paper addresses the topic by providing not only a renewed discussion, but also an improved energy poverty indicator (with clear and relevant results at the EU level): the Compound Energy Poverty Indicator (CEPI). Moreover, knowing that the risk of poverty and social exclusion, efficiency of heating systems, total consumption of energy per household and rising energy prices tend to increase the severity of this problem in some countries, CEPI is then included into an econometric model so as to determine some possible factors that tend to put pressure on an already existing issue of energy poverty. The results of this research are expected to be relevant not only for academics (as it offers insights into the structure and severity of this topic within the European Union), but also for national and EU policymakers who are confronted in the field with the problem of sustainable development. Full article

(This article belongs to the Special Issue Sustainable Energy Storage Applications for Renewable Generation Support)

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Other

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2678 KiB

Open AccessCase Report

Utilizing a Novel Approach at the Fuzzy Front-End of New Product Development: A Case Study in a Flexible Fabric Supercapacitor

by Gwo-Tsuen Jou and Benjamin J. C. Yuan

Sustainability 2016, 8(8), 740; https://0-doi-org.brum.beds.ac.uk/10.3390/su8080740 - 03 Aug 2016

Cited by 10 | Viewed by 5790

Abstract

The fuzzy front-end plays a most crucial part in new product development (NPD), leading to the success of product development and product launch in the market. This study proposes a novel method, TTRI_MP, by combining Crawford and Di Benedetto’s model and Cooper’s model, [...] Read more.

The fuzzy front-end plays a most crucial part in new product development (NPD), leading to the success of product development and product launch in the market. This study proposes a novel method, TTRI_MP, by combining Crawford and Di Benedetto’s model and Cooper’s model, to strengthen the management of the fuzzy front-end. The proposed method comprises four stages: market exploration and technology forecasting, idea generation and segmentation, portfolio analysis and technology roadmapping (TRM). In the first stage, SWOT was utilized to identify the key strategic areas, and the technology readiness level (TRL) was adopted to position the level of developed technologies. In the second stage, the business concepts were required to go through the viability test and customers, collaborators, competitors and company (4C). In the third stage, the Strategic Position Analysis (SPAN) and Financial Analysis (FAN) developed by IBM were employed in the portfolio analysis to screen out potential NPD projects. In the last stage, the selected NPD projects were linked with their functions and technologies in the TRM chart. The method was successfully implemented by a research team working on a flexible fabric supercapacitor at the Taiwan Textile Research Institute (TTRI). Full article

(This article belongs to the Special Issue Sustainable Energy Storage Applications for Renewable Generation Support)

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