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6367 KiB

Open AccessArticle

A Techno-Economic Study of an Entirely Renewable Energy-Based Power Supply for North America for 2030 Conditions

by Arman Aghahosseini, Dmitrii Bogdanov and Christian Breyer

Energies 2017, 10(8), 1171; https://doi.org/10.3390/en10081171 - 09 Aug 2017

Cited by 69 | Viewed by 12931

In this study power generation and demand are matched through a least-cost mix of renewable energy (RE) resources and storage technologies for North America by 2030. The study is performed using an hourly resolved model based on a linear optimization algorithm. The geographical, [...] Read more.

In this study power generation and demand are matched through a least-cost mix of renewable energy (RE) resources and storage technologies for North America by 2030. The study is performed using an hourly resolved model based on a linear optimization algorithm. The geographical, technical and economic potentials of different forms of RE resources enable the option of building a super grid between different North American regions. North America (including the U.S., Canada and Mexico in this paper), is divided into 20 sub-regions based on their population, demand, area and electricity grid structure. Four scenarios have been evaluated: region-wide, country-wide, area-wide and an integrated scenario. The levelised cost of electricity is found to be quite attractive in such a system, with the range from 63 €/MWh_el in a decentralized case and 42 €/MWh_el in a more centralized and integrated scenario. Electrical grid interconnections significantly reduce the storage requirement and overall cost of the energy system. Among all RE resources, wind and solar PV are found to be the least-cost options and hence the main contributors to fossil fuel substitution. The results clearly show that a 100% RE-based system is feasible and a real policy option at a modest cost. However, such a tremendous transition will not be possible in a short time if policy-makers, energy investors and other relevant organizations do not support the proposed system. Full article

(This article belongs to the Special Issue Sustainable Energy Technologies)

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1545 KiB

Open AccessArticle

Smart Integrated Renewable Energy Systems (SIRES): A Novel Approach for Sustainable Development

by Zeel Maheshwari and Rama Ramakumar

Energies 2017, 10(8), 1145; https://doi.org/10.3390/en10081145 - 04 Aug 2017

Cited by 30 | Viewed by 11478

Abstract

Technical and economic aspects of the viability of SIRES (Smart Integrated Renewable Energy Systems) for sustainable development of remote and rural areas of the world are discussed. The hallmark of the proposed SIRES is the smart utilization of several renewable resources in an [...] Read more.

Technical and economic aspects of the viability of SIRES (Smart Integrated Renewable Energy Systems) for sustainable development of remote and rural areas of the world are discussed. The hallmark of the proposed SIRES is the smart utilization of several renewable resources in an integrated fashion and matching of resources and needs a priori with the ultimate goal of “energization”, not just “electrification”. Historical background leading to this approach is succinctly presented along with a comprehensive schematic diagram. Modeling of various components and their collective use in optimizing SIRES with the aid of genetic algorithm are presented using a typical hypothetical example. SIRES is also compared with various approaches for rural development based on Annualized Cost of System (ACS) and installation costs. Implementation of SIRES will lead to overall sustainable development of rural communities. Full article

(This article belongs to the Special Issue Sustainable Energy Technologies)

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4771 KiB

Open AccessArticle

Nonlinear Observer-Based Robust Passive Control of Doubly-Fed Induction Generators for Power System Stability Enhancement via Energy Reshaping

by Jun Dong, Shengnan Li, Shuijun Wu, Tingyi He, Bo Yang, Hongchun Shu and Jilai Yu

Energies 2017, 10(8), 1082; https://doi.org/10.3390/en10081082 - 25 Jul 2017

Cited by 15 | Viewed by 4366

Abstract

The large-scale penetration of wind power might lead to degradation of the power system stability due to its inherent feature of randomness. Hence, proper control designs which can effectively handle various uncertainties become very crucial. This paper designs a novel robust passive control [...] Read more.

The large-scale penetration of wind power might lead to degradation of the power system stability due to its inherent feature of randomness. Hence, proper control designs which can effectively handle various uncertainties become very crucial. This paper designs a novel robust passive control (RPC) scheme of a doubly-fed induction generator (DFIG) for power system stability enhancement. The combinatorial effect of generator nonlinearities and parameter uncertainties, unmodelled dynamics, wind speed randomness, is aggregated into a perturbation, which is rapidly estimated by a nonlinear extended state observer (ESO) in real-time. Then, the perturbation estimate is fully compensated by a robust passive controller to realize a globally consistent control performance, in which the energy of the closed-loop system is carefully reshaped through output feedback passification, such that a considerable system damping can be injected to improve the transient responses of DFIG in various operation conditions of power systems. Six case studies are carried out while simulation results verify that RPC can rapidly stabilize the disturbed DFIG system much faster with less overshoot, as well as supress power oscillations more effectively compared to that of linear proportional-integral-derivative (PID) control and nonlinear feedback linearization control (FLC). Full article

(This article belongs to the Special Issue Sustainable Energy Technologies)

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1821 KiB

Open AccessArticle

Flexibility-Based Evaluation of Variable Generation Acceptability in Korean Power System

by Chang-Gi Min and Mun-Kyeom Kim

Energies 2017, 10(6), 825; https://doi.org/10.3390/en10060825 - 18 Jun 2017

Cited by 15 | Viewed by 4492

Abstract

This study proposes an evaluation method for variable generation (VG) acceptability with an adequate level of power system flexibility. In this method, a risk index referred to as the ramping capability shortage expectation (RSE) is used to quantify flexibility. The RSE [...] Read more.

This study proposes an evaluation method for variable generation (VG) acceptability with an adequate level of power system flexibility. In this method, a risk index referred to as the ramping capability shortage expectation (RSE) is used to quantify flexibility. The RSE value of the current power system is selected as the adequate level of flexibility (i.e., RSE criterion). VG acceptability is represented by the VG penetration level for the RSE criterion. The proposed evaluation method was applied to the generation expansion plan in Korea for 2029 in order to examine the validity of the existing plan for VG penetration. Sensitivity analysis was also performed to analyze the effects of changes in system uncertainty on VG acceptability. The results show that the planned VG penetration level for 2029 can improve by approximately 12% while securing flexibility. Full article

(This article belongs to the Special Issue Sustainable Energy Technologies)

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5085 KiB

Open AccessEditor’s ChoiceArticle

A Cost Optimized Fully Sustainable Power System for Southeast Asia and the Pacific Rim

by Ashish Gulagi, Dmitrii Bogdanov and Christian Breyer

Energies 2017, 10(5), 583; https://doi.org/10.3390/en10050583 - 25 Apr 2017

Cited by 47 | Viewed by 8676

Abstract

In this paper, a cost optimal 100% renewable energy based system is obtained for Southeast Asia and the Pacific Rim region for the year 2030 on an hourly resolution for the whole year. For the optimization, the region was divided into 15 sub-regions [...] Read more.

In this paper, a cost optimal 100% renewable energy based system is obtained for Southeast Asia and the Pacific Rim region for the year 2030 on an hourly resolution for the whole year. For the optimization, the region was divided into 15 sub-regions and three different scenarios were set up based on the level of high voltage direct current grid connections. The results obtained for a total system levelized cost of electricity showed a decrease from 66.7 €/MWh in a decentralized scenario to 63.5 €/MWh for a centralized grid connected scenario. An integrated scenario was simulated to show the benefit of integrating additional demand of industrial gas and desalinated water which provided the system the required flexibility and increased the efficiency of the usage of storage technologies. This was reflected in the decrease of system cost by 9.5% and the total electricity generation by 5.1%. According to the results, grid integration on a larger scale decreases the total system cost and levelized cost of electricity by reducing the need for storage technologies due to seasonal variations in weather and demand profiles. The intermittency of renewable technologies can be effectively stabilized to satisfy hourly demand at a low cost level. A 100% renewable energy based system could be a reality economically and technically in Southeast Asia and the Pacific Rim with the cost assumptions used in this research and it may be more cost competitive than the nuclear and fossil carbon capture and storage (CCS) alternatives. Full article

(This article belongs to the Special Issue Sustainable Energy Technologies)

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1934 KiB

Open AccessArticle

Wind Power Potentials in Cameroon and Nigeria: Lessons from South Africa

by Abdullahi Abubakar Mas’ud, Asan Vernyuy Wirba, Jorge Alfredo Ardila-Rey, Ricardo Albarracín, Firdaus Muhammad-Sukki, Álvaro Jaramillo Duque, Nurul Aini Bani and Abu Bakar Munir

Energies 2017, 10(4), 443; https://doi.org/10.3390/en10040443 - 27 Mar 2017

Cited by 23 | Viewed by 7907

Abstract

Wind energy has seen a tremendous growth for electricity generation worldwide and reached 456 GW by the end of June 2016. According to the World Wind Energy Association, global wind power will reach 500 GW by the end of 2016. Africa is a [...] Read more.

Wind energy has seen a tremendous growth for electricity generation worldwide and reached 456 GW by the end of June 2016. According to the World Wind Energy Association, global wind power will reach 500 GW by the end of 2016. Africa is a continent that possesses huge under-utilized wind potentials. Some African countries, e.g., Morocco, Egypt, Tunisia and South Africa, have already adopted wind as an alternative power generation source in their energy mix. Among these countries, South Africa has invested heavily in wind energy with operational wind farms supplying up to 26,000 GWh annually to the national grid. However, two African countries, i.e., Cameroon and Nigeria, have vast potentials, but currently are lagging behind in wind energy development. For Nigeria, there is slow implementation of renewable energy policy, with no visible operational wind farms; while Cameroon does not have any policy plan for wind power. These issues are severely hindering both direct foreign and local investments into the electricity sector. Cameroon and Nigeria have huge wind energy potentials with similar climatic conditions and can benefit greatly from the huge success recorded in South Africa in terms of policy implementation, research, development and technical considerations. Therefore, this paper reviews the wind energy potentials, policies and future renewable energy road-maps in Cameroon and Nigeria and identifies their strength and weakness, as well as providing necessary actions for future improvement that South Africa has already adopted. Full article

(This article belongs to the Special Issue Sustainable Energy Technologies)

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1576 KiB

Open AccessArticle

A Novel Multi-Objective Optimal Approach for Wind Power Interval Prediction

by Mengyue Hu, Zhijian Hu, Jingpeng Yue, Menglin Zhang and Meiyu Hu

Energies 2017, 10(4), 419; https://doi.org/10.3390/en10040419 - 23 Mar 2017

Cited by 33 | Viewed by 3882

Abstract

Numerous studies on wind power forecasting show that random errors found in the prediction results cause uncertainty in wind power prediction and cannot be solved effectively using conventional point prediction methods. In contrast, interval prediction is gaining increasing attention as an effective approach [...] Read more.

Numerous studies on wind power forecasting show that random errors found in the prediction results cause uncertainty in wind power prediction and cannot be solved effectively using conventional point prediction methods. In contrast, interval prediction is gaining increasing attention as an effective approach as it can describe the uncertainty of wind power. A wind power interval forecasting approach is proposed in this article. First, the original wind power series is decomposed into a series of subseries using variational mode decomposition (VMD); second, the prediction model is established through kernel extreme learning machine (KELM). Three indices are taken into account in a novel objective function, and the improved artificial bee colony algorithm (IABC) is used to search for the best wind power intervals. Finally, when compared with other competitive methods, the simulation results show that the proposed approach has much better performance. Full article

(This article belongs to the Special Issue Sustainable Energy Technologies)

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2543 KiB

Open AccessArticle

Sustainable Energy Transitions in China: Renewable Options and Impacts on the Electricity System

by Xiaoyang Sun, Baosheng Zhang, Xu Tang, Benjamin C. McLellan and Mikael Höök

Energies 2016, 9(12), 980; https://doi.org/10.3390/en9120980 - 25 Nov 2016

Cited by 54 | Viewed by 8438

Abstract

Chinese energy consumption has been dominated by coal for decades, but this needs to change to protect the environment and mitigate anthropogenic climate change. Renewable energy development is needed to fulfil the Intended Nationally Determined Contribution (INDC) for the post-2020 period, as stated [...] Read more.

Chinese energy consumption has been dominated by coal for decades, but this needs to change to protect the environment and mitigate anthropogenic climate change. Renewable energy development is needed to fulfil the Intended Nationally Determined Contribution (INDC) for the post-2020 period, as stated on the 2015 United Nations Climate Change Conference in Paris. This paper reviews the potential of renewable energy in China and how it could be utilised to meet the INDC goals. A business-as-usual case and eight alternative scenarios with 40% renewable electricity are explored using the EnergyPLAN model to visualise out to the year 2030. Five criteria (total cost, total capacity, excess electricity, CO₂ emissions, and direct job creation) are used to assess the sustainability of the scenarios. The results indicate that renewables can meet the goal of a 20% share of non-fossil energy in primary energy and 40%–50% share of non-fossil energy in electricity power. The low nuclear-hydro power scenario is the most optimal scenario based on the used evaluation criteria. The Chinese government should implement new policies aimed at promoting integrated development of wind power and solar PV. Full article

(This article belongs to the Special Issue Sustainable Energy Technologies)

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5786 KiB

Open AccessArticle

Flow Induced Vibration and Energy Extraction of an Equilateral Triangle Prism at Different System Damping Ratios

by Jun Zhang, Fang Liu, Jijian Lian, Xiang Yan and Quanchao Ren

Energies 2016, 9(11), 938; https://doi.org/10.3390/en9110938 - 10 Nov 2016

Cited by 23 | Viewed by 4797

Abstract

The flow induced vibration and energy extraction of an equilateral triangle prism elastically mounted in a water channel are investigated experimentally at different system damping ratios ζ_total with the constant oscillating mass M_osc and system stiffness K. A power take-off [...] Read more.

The flow induced vibration and energy extraction of an equilateral triangle prism elastically mounted in a water channel are investigated experimentally at different system damping ratios ζ_total with the constant oscillating mass M_osc and system stiffness K. A power take-off system with a variable damping function is developed. The translation-rotation equation of the vibration system deduced in the study indicates that the total oscillating mass includes the material mass, and the equivalent mass due to the rotation of the gears and rotor. Besides, increasing load resistance can result in a decrease in ζ_total when K and M_osc remain unchanged. The prism experiences, in turn, soft galloping, hard galloping 1 and hard galloping 2 with increasing ζ_total. As ζ_total increases up to 0.335, only the vortex-induced vibration is observed because the extremely high ζ_total prevents the prism from galloping. The response amplitude decreases with the increasing ζ_total. In addition, higher ζ_total promotes the galloping to start at a higher reduced velocity. The galloping characteristics of the prism, including large amplitude responses in an extremely large range of flow velocities, excellent vibration stationarity, and steady vibration frequencies, are beneficial for improving energy conversion. The prism can extract hydraulic energy for the flow velocity U > 0.610 m/s. The harnessed power P_out and the energy conversion efficiency η_out increase with increasing ζ_total in the galloping zone. The maximum P_out and η_out reach 53.56 W and 40.44%, respectively. The optimal system damping ratio for extracting energy is the maximum system damping ratio that the prism can overcome to experience stable galloping. Full article

(This article belongs to the Special Issue Sustainable Energy Technologies)

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Review

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4241 KiB

Open AccessReview

Green and Sustainable Cellular Base Stations: An Overview and Future Research Directions

by Mohammed H. Alsharif, Jeong Kim and Jin Hong Kim

Energies 2017, 10(5), 587; https://doi.org/10.3390/en10050587 - 25 Apr 2017

Cited by 66 | Viewed by 10294

Abstract

Energy efficiency and renewable energy are the main pillars of sustainability and environmental compatibility. This study presents an overview of sustainable and green cellular base stations (BSs), which account for most of the energy consumed in cellular networks. We review the architecture of [...] Read more.

Energy efficiency and renewable energy are the main pillars of sustainability and environmental compatibility. This study presents an overview of sustainable and green cellular base stations (BSs), which account for most of the energy consumed in cellular networks. We review the architecture of the BS and the power consumption model, and then summarize the trends in green cellular network research over the past decade. As its major contribution, this study highlights the uses of renewable energy in cellular communication by: (i) investigating the system model and the potential of renewable energy solutions for cellular BSs; (ii) identifying the potential geographical locations for renewable-energy-powered BSs; (iii) performing case studies on renewable-energy-powered cellular BSs and suggesting future research directions based on our findings; (iv) examining the present deployment of sustainable and green BSs; and (v) studying the barriers that prevent the widespread use of renewable-energy-powered BSs and providing recommendations for future work. Full article

(This article belongs to the Special Issue Sustainable Energy Technologies)

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