Energies

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847 KiB

Open AccessArticle

Measurement Research on the Decoupling Effect of Industries’ Carbon Emissions—Based on the Equipment Manufacturing Industry in China

by Lu Wan, Zi-Long Wang and Jhony Choon Yeong Ng

Energies 2016, 9(11), 921; https://doi.org/10.3390/en9110921 - 8 Nov 2016

Cited by 31 | Viewed by 4735

Abstract

Economic development usually leads to increased energy consumption, which in turn will result in an increase in carbon emissions. To break the relationship between economic development and carbon emissions, scholars have turned their attention to the phenomenon of decoupling. In this paper, we [...] Read more.

Economic development usually leads to increased energy consumption, which in turn will result in an increase in carbon emissions. To break the relationship between economic development and carbon emissions, scholars have turned their attention to the phenomenon of decoupling. In this paper, we studied the decoupling relationship between carbon emissions and economic growth of the equipment manufacturing industry in China from 2000 to 2014. We adapted the LMDI decomposition method, and we used the Tapio decoupling evaluation model to analyze our data. We found that the decoupling relationship between carbon emissions and economic growth of China’s equipment manufacturing industry is weak, which indicates the industry is experiencing faster economic growth than carbon emission growth. We found the economic output is the factor that has the strongest influence on the industry’s carbon emission, and energy consumption intensity has the strongest relationship with the decoupling of economic growth and carbon emission. The indicators of the industry’s decoupling-effort are all less than 1.0, which indicates that the industry is in the state of weak decoupling, and we also observed an annual decreasing trend in the industry’s indicators. Toward the end of this paper, we used the Grey forecasting model to predict the decoupling relationship between carbon emission and economic growth for 2015–2024, and we discussed the implications of our research. Full article

(This article belongs to the Special Issue Energy-Efficient and Sustainable Networking)

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558 KiB

Open AccessArticle

Spatial and Temporal Traffic Variation in Core Networks: Impact on Energy Saving and Devices Lifetime

by Filip Idzikowski, Frank Pfeuffer, Axel Werner and Luca Chiaraviglio

Energies 2016, 9(10), 837; https://doi.org/10.3390/en9100837 - 19 Oct 2016

Viewed by 4158

Abstract

We assess the impact of traffic variations on energy consumption and devices lifetime in a core network. Specifically, we first define a model to control the spatial as well as the temporal variations of traffic. We generate different sets of traffic matrices by [...] Read more.

We assess the impact of traffic variations on energy consumption and devices lifetime in a core network. Specifically, we first define a model to control the spatial as well as the temporal variations of traffic. We generate different sets of traffic matrices by adopting our model, which are then used as input to an energy-aware algorithm, with the aim of finding the set of Line Cards (LCs) in Sleep Mode (SM) for each traffic matrix. Given this output, we are able to compute different evaluation metrics, including: the total energy consumption, the normalized lifetime as a consequence of activation/deactivation of network devices, and the total network profitability (i.e., the monetary gain/loss for the operator). Our results show that the temporal variation of traffic affects the LCs energy consumption, but has a limited impact on their lifetime. Moreover, the spatial variation of traffic is no obstacle for energy saving. Eventually, the frequency of the power cycles, introduced by the energy-aware algorithm, is particularly important for the lifetime of LCs. Finally, we show that positive total profitability is achieved in most of the considered cases. Full article

(This article belongs to the Special Issue Energy-Efficient and Sustainable Networking)

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4897 KiB

Open AccessArticle

Smart Monitoring Embedded Service for Energy-Efficient and Sustainable Management in Data Centers

by Diego Marcos-Jorquera, Virgilio Gilart-Iglesias, Francisco José Mora-Gimeno and Juan Antonio Gil-Martínez-Abarca

Energies 2016, 9(7), 515; https://doi.org/10.3390/en9070515 - 1 Jul 2016

Cited by 5 | Viewed by 4486

Abstract

Information technologies (IT) currently represent 2% of CO₂ emissions. In recent years, a wide variety of IT solutions have been proposed, focused on increasing the energy efficiency of network data centers. Monitoring is one of the fundamental pillars of these systems, providing [...] Read more.

Information technologies (IT) currently represent 2% of CO₂ emissions. In recent years, a wide variety of IT solutions have been proposed, focused on increasing the energy efficiency of network data centers. Monitoring is one of the fundamental pillars of these systems, providing the information necessary for adequate decision making. However, today’s monitoring systems (MSs) are partial, specific and highly coupled solutions. This study proposes a model for monitoring data centers that serves as a basis for energy saving systems, offered as a value-added service embedded in a device with low cost and power consumption. The proposal is general in nature, comprehensive, scalable and focused on heterogeneous environments, and it allows quick adaptation to the needs of changing and dynamic environments. Further, a prototype of the system has been implemented in several devices, which has allowed validation of the proposal in addition to identification of the minimum hardware profile required to support the model. Full article

(This article belongs to the Special Issue Energy-Efficient and Sustainable Networking)

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1669 KiB

Open AccessArticle

Greening the NetFPGA Reference Router

by Feng Guo, Xiaojun Wang, Mei Song, Yifei Wei, Olga Ormond and Martin Collier

Energies 2016, 9(7), 500; https://doi.org/10.3390/en9070500 - 29 Jun 2016

Cited by 2 | Viewed by 5785

Abstract

Energy efficiency is an important criterion in the design of next generation networks for both economic and environmental concerns. This paper presents an energy-efficient router that is able to dynamically adapt its routing capability in response to real-time traffic load, achieving energy proportional [...] Read more.

Energy efficiency is an important criterion in the design of next generation networks for both economic and environmental concerns. This paper presents an energy-efficient router that is able to dynamically adapt its routing capability in response to real-time traffic load, achieving energy proportional routing. The NetFPGA reference router, which operates at one of two frequencies (125 MHz or 62.5 MHz), requires a board reset to switch frequencies. We have modified the reference router to allow dynamic switching among five operating frequencies. Experiments with real traces indicate that, compared to the reference router, a 10% power reduction can be achieved through dynamic frequency scaling. When the router is further modified to support green traffic engineering and Ethernet port shut-down, power consumption can be reduced by 46% while maintaining the required quality of service. This allows the router to meet the instantaneous performance requirements while minimizing power dissipation. Similar results can be expected when these general power-saving principles are applied in future commercial routers. Full article

(This article belongs to the Special Issue Energy-Efficient and Sustainable Networking)

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616 KiB

Open AccessArticle

Lifetime-Aware Cloud Data Centers: Models and Performance Evaluation

by Luca Chiaraviglio, Antonio Cianfrani, Marco Listanti, William Liu and Marco Polverini

Energies 2016, 9(6), 470; https://doi.org/10.3390/en9060470 - 18 Jun 2016

Cited by 8 | Viewed by 4223

Abstract

We present a model to evaluate the server lifetime in cloud data centers (DCs). In particular, when the server power level is decreased, the failure rate tends to be reduced as a consequence of the limited number of components powered on. However, the [...] Read more.

We present a model to evaluate the server lifetime in cloud data centers (DCs). In particular, when the server power level is decreased, the failure rate tends to be reduced as a consequence of the limited number of components powered on. However, the variation between the different power states triggers a failure rate increase. We therefore consider these two effects in a server lifetime model, subject to an energy-aware management policy. We then evaluate our model in a realistic case study. Our results show that the impact on the server lifetime is far from negligible. As a consequence, we argue that a lifetime-aware approach should be pursued to decide how and when to apply a power state change to a server. Full article

(This article belongs to the Special Issue Energy-Efficient and Sustainable Networking)

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1608 KiB

Open AccessEditor’s ChoiceArticle

Optimal Scheduling of Energy Storage System for Self-Sustainable Base Station Operation Considering Battery Wear-Out Cost

by Yohwan Choi and Hongseok Kim

Energies 2016, 9(6), 462; https://doi.org/10.3390/en9060462 - 16 Jun 2016

Cited by 57 | Viewed by 7872

Abstract

A self-sustainable base station (BS) where renewable resources and energy storage system (ESS) are interoperably utilized as power sources is a promising approach to save energy and operational cost in communication networks. However, high battery price and low utilization of ESS intended for [...] Read more.

A self-sustainable base station (BS) where renewable resources and energy storage system (ESS) are interoperably utilized as power sources is a promising approach to save energy and operational cost in communication networks. However, high battery price and low utilization of ESS intended for uninterruptible power supply (UPS) necessitates active utilization of ESS. This paper proposes a multi-functional framework of ESS using dynamic programming (DP) for realizing a sustainable BS. We develop an optimal charging and discharging scheduling algorithm considering a detailed battery wear-out model to minimize operational cost as well as to prolong battery lifetime. Our approach significantly reduces total cost compared to the conventional method that does not consider battery wear-out. Extensive experiments for several scenarios exhibit that total cost is reduced by up to 70.6% while battery wear-out is also reduced by 53.6%. The virtue of the proposed framework is its wide applicability beyond sustainable BS and thus can be also used for other types of load in principle. Full article

(This article belongs to the Special Issue Energy-Efficient and Sustainable Networking)

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726 KiB

Open AccessArticle

A Biologically-Inspired Power Control Algorithm for Energy-Efficient Cellular Networks

by Hyun-Ho Choi and Jung-Ryun Lee

Energies 2016, 9(3), 161; https://doi.org/10.3390/en9030161 - 4 Mar 2016

Cited by 4 | Viewed by 4912

Abstract

Most of the energy used to operate a cellular network is consumed by a base station (BS), and reducing the transmission power of a BS can therefore afford a substantial reduction in the amount of energy used in a network. In this paper, [...] Read more.

Most of the energy used to operate a cellular network is consumed by a base station (BS), and reducing the transmission power of a BS can therefore afford a substantial reduction in the amount of energy used in a network. In this paper, we propose a distributed transmit power control (TPC) algorithm inspired by bird flocking behavior as a means of improving the energy efficiency of a cellular network. Just as each bird in a flock attempts to match its velocity with the average velocity of adjacent birds, in the proposed algorithm, each mobile station (MS) in a cell matches its rate with the average rate of the co-channel MSs in adjacent cells by controlling the transmit power of its serving BS. We verify that this bio-inspired TPC algorithm using a local rate-average process achieves an exponential convergence and maximizes the minimum rate of the MSs concerned. Simulation results show that the proposed TPC algorithm follows the same convergence properties as the flocking algorithm and also effectively reduces the power consumption at the BSs while maintaining a low outage probability as the inter-cell interference increases; in so doing, it significantly improves the energy efficiency of a cellular network. Full article

(This article belongs to the Special Issue Energy-Efficient and Sustainable Networking)

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797 KiB

Open AccessArticle

Life is Short: The Impact of Power States on Base Station Lifetime

by Luca Chiaraviglio, Marco Listanti and Edoardo Manzia

Energies 2015, 8(12), 14407-14426; https://doi.org/10.3390/en81212435 - 19 Dec 2015

Cited by 6 | Viewed by 4654

Abstract

We study the impact of power state transitions on the lifetime of base stations (BSs) in mobile networks. In particular, we propose a model to estimate the lifetime decrease/increase as a consequence of the application of power state changes. The model takes into [...] Read more.

We study the impact of power state transitions on the lifetime of base stations (BSs) in mobile networks. In particular, we propose a model to estimate the lifetime decrease/increase as a consequence of the application of power state changes. The model takes into account both hardware (HW) parameters, which depend on the materials used to build the device, and power state parameters, that instead depend on how and when power state transitions take place. More in depth, we consider the impact of different power states when a BS is active, and one sleep mode state when a BS is powered off. When a BS reduces the power consumption, its lifetime tends to increase. However, when a BS changes the power state, its lifetime tends to be decreased. Thus, there is a tradeoff between these two effects. Our results, obtained over universal mobile telecommunication system (UMTS) and long term evolution (LTE) case studies, indicate the need of a careful management of the power state transitions in order to not deteriorate the BS lifetime, and consequently to not increase the associated reparation/replacement costs. Full article

(This article belongs to the Special Issue Energy-Efficient and Sustainable Networking)

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