Energy efficiency considerations in integrated IT and optical network resilient infrastructures

The European Integrated Project GEYSERS - Generalised Architecture for Dynamic Infrastructure Services - is concentrating on infrastructures incorporating integrated optical network and IT resources in support of the Future Internet with special emphasis on cloud computing. More specifically GEYSERS proposes the concept of Virtual Infrastructures over one or more interconnected Physical Infrastructures comprising both network and IT resources. Taking into consideration the energy consumption levels associated with the ICT today and the expansion of the Internet in size and complexity, that incurring increased energy consumption of both IT and network resources, energy efficient infrastructure design becomes critical. To address this need, in the framework of GEYSERS, we propose energy efficient design of infrastructures incorporating integrated optical network and IT resources, supporting resilient end-to-end services. Our modeling results quantify significant energy savings of the proposed solution by jointly optimizing the allocation of both network and IT resources

Cell sleeping for energy efficiency in cellular networks: Is it viable?

An approach advocated in the recent literature for reducing energy consumption in cellular networks is to put base stations to sleep when traffic loads are low. However, several practical considerations are ignored in these studies. In this paper, we aim to raise questions on the feasibility and benefits of base station sleeping. Specifically we analyze the interference and capacity of a coverage-based energy reduction system in CDMA based cellular networks using a simple analytical model and show that sleeping may not be a feasible solution to reduce energy consumption in many scenarios. © 2012 IEEE

Exploring employee energy efficiency awareness in UK commercial offices: IT and small power

Energy consumption reduction is called upon across UK business facilities in order to mitigate the rising impacts of climate change. Business facilities such as office buildings rely on a range of electrical equipment on a day-to-day basis (Carbon Trust 2005b). However, it is not always appreciated how much electrical equipment can cost a company (Carbon Trust 2005b). The need for businesses to assess their current office energy use and seek ways to significantly improve their energy efficiency and energy cost is increasing (Pellegrini-Masini and Leishman 2011).The implementation and effectiveness of energy-efficient measures within a commercial office environment is reported as a key to the success of improving a business’ energy efficiency (DECC 2012; Westminster Sustainable Business Forum 2013). Office electrical equipment can be responsible for up to 30% of total energy consumption. Using equipment more efficiently is suggested to enable a difference to energy use and spending (Npower 2010).Individual IT equipment and small appliances is an area where wasteful electricity consumption can often occur through the inefficient use. Typically, desktop and associated IT equipment such as computers, printers, modems and fax machines average about 160 W per work location commercial offices (BRECSU 2000). According to Bray (2006), employee usage patterns relating to IT equipment and small power appliance use are a more important factor in determining energy consumption than the energy efficiency ratings of the equipment itself. In addition, out-of-hours usage is a common issue which needs further investigation by exploring small power behaviour of office workers when leaving at the end of the working day (Bray 2006).The purpose of this survey-based approach paper is to examine employee awareness and behaviour regarding energy efficiency implementation in commercial office buildings in the UK, with a focus on IT and small power equipment. The IT and small power equipment which are included as part of this study are laptops, desktop computers, printers, teleconference equipment, fax machines, kettles and microwaves. The following sections discuss key literature on the topic followed by a section on research methods. This is followed by a discussion of key findings, discussion and conclusion outlining key contributions and implications

Introducing Energy Efficiency into SQALE

Energy Efficiency is becoming a key factor in software development, given the sharp growth of IT systems and their impact on worldwide energy consumption. We do believe that a quality process infrastructure should be able to consider the Energy Efficiency of a system since its early development: for this reason we propose to introduce Energy Efficiency into the existing quality models. We selected the SQALE model and we tailored it inserting Energy Efficiency as a sub-characteristic of efficiency. We also propose a set of six source code specific requirements for the Java language starting from guidelines currently suggested in the literature. We experienced two major challenges: the identification of measurable, automatically detectable requirements, and the lack of empirical validation on the guidelines currently present in the literature and in the industrial state of the practice as well. We describe an experiment plan to validate the six requirements and evaluate the impact of their violation on Energy Efficiency, which has been partially proved by preliminary results on C code. Having Energy Efficiency in a quality model and well verified code requirements to measure it, will enable a quality process that precisely assesses and monitors the impact of software on energy consumptio

Energy demand and energy efficiency in the OECD countries: a stochastic demand frontier approach

This paper attempts to estimate a panel ‘frontier’ whole economy aggregate energy demand function for 29 countries over the period 1978 to 2006 using stochastic frontier analysis (SFA). Consequently, unlike standard energy demand econometric estimation, the energy efficiency of each country is also modelled and it is argued that this represents a measure of the underlying efficiency for each country over time, as well as the relative efficiency across the 29 OECD countries. This shows that energy intensity is not necessarily a good indicator of energy efficiency, whereas by controlling for a range of economic and other factors, the measure of energy efficiency obtained via this approach is. This is, as far as is known, the first attempt to model energy demand and efficiency in this way and it is arguably particularly relevant in a world dominated by environmental concerns with the subsequent need to conserve energy and/or use it as efficiently as possible. Moreover, the results show that although for a number of countries the change in energy intensity over time might give a reasonable indication of efficiency improvements; this is not always the case. Therefore, unless this analysis is undertaken, it is not possible to know whether the energy intensity of a country is a good proxy for energy efficiency or not. Hence, it is argued that this analysis should be undertaken to avoid potentially misleading advice to policy makers.Energy demand; OECD; efficiency and frontier analysis; energy efficiency

Assessing the effects of technological progress on energy efficiency in the construction industry: A case of China

Energy-saving technologies in buildings have received great attention from energy efficiency researchers in the construction sector. Traditional research tends to focus on the energy used during building operation and in construction materials production, but it usually neglects the energy consumed in the building construction process. Very few studies have explored the impacts of technological progress on energy efficiency in the construction industry. This paper presents a model of the building construction process based on Cobb-Douglas production function. The model estimates the effects of technological progress on energy efficiency with the objective to examine the role that technological progress plays in energy savings in China's construction industry. The modeling results indicated that technological progress improved energy efficiency by an average of 7.1% per year from 1997 to 2014. Furthermore, three main technological progress factors (the efficiency of machinery and equipment, the proportion change of the energy structure, and research and development investment) were selected to analyze their effects on energy efficiency improvement. These positive effects were verified, and results show the effects of first two factors are significant. Finally, recommendations for promoting energy efficiency in the construction industry are proposed

Net Energy Index: A New Way To Measure Energy Efficient Buildings

Energy efficiency indexes are useful for providing tangible measurements of energy efficiency in buildings. Buildings use approximately 70% of all electricity in the USA. Using that energy efficiently has two primary benefits: limiting greenhouse gas emissions and reducing grid strain. Utilizing local renewable energy sources contributes to the same benefits. Currently, there is no index that considers renewable energy sources when measuring energy efficiency. Therefore, this paper proposes the Net Energy Index, which compares the net power usage of a building to the floor area of the building in order to determine energy efficiency. If renewable energy supplies power to a building, this index is not only useful and justified, but it is also practical through advances in energy meters

Energy-delay bounds analysis in wireless multi-hop networks with unreliable radio links

Energy efficiency and transmission delay are very important parameters for wireless multi-hop networks. Previous works that study energy efficiency and delay are based on the assumption of reliable links. However, the unreliability of the channel is inevitable in wireless multi-hop networks. This paper investigates the trade-off between the energy consumption and the end-to-end delay of multi-hop communications in a wireless network using an unreliable link model. It provides a closed form expression of the lower bound on the energy-delay trade-off for different channel models (AWGN, Raleigh flat fading and Nakagami block-fading) in a linear network. These analytical results are also verified in 2-dimensional Poisson networks using simulations. The main contribution of this work is the use of a probabilistic link model to define the energy efficiency of the system and capture the energy-delay trade-offs. Hence, it provides a more realistic lower bound on both the energy efficiency and the energy-delay trade-off since it does not restrict the study to the set of perfect links as proposed in earlier works

US Residential Energy Demand and Energy Efficiency: A Stochastic Demand Frontier Approach

This paper estimates a US ‘frontier’ residential aggregate energy demand function using panel data for 48 ‘states’ over the period 1995 to 2006 using stochastic frontier analysis (SFA). Utilizing an econometric energy demand model, the (in) efficiency of each state is modelled and it is argued that this represents a measure of the inefficient use of residential energy in each state (i.e. ‘waste energy’). This underlying efficiency for the US is therefore observed for each state as well as the relative efficiency across the states. Moreover, the analysis suggests that energy intensity is not necessarily a good indicator of energy efficiency, whereas by controlling for a range of economic and other factors, the measure of energy efficiency obtained via this approach is. This is a novel approach to model residential energy demand and efficiency and it is arguably particularly relevant given current US energy policy discussions related to energy efficiency.Energy demand; US residential energy demand; efficiency and frontier analysis; state energy efficiency.

Iso-energy-efficiency: An approach to power-constrained parallel computation

Future large scale high performance supercomputer systems require high energy efficiency to achieve exaflops computational power and beyond. Despite the need to understand energy efficiency in high-performance systems, there are few techniques to evaluate energy efficiency at scale. In this paper, we propose a system-level iso-energy-efficiency model to analyze, evaluate and predict energy-performance of data intensive parallel applications with various execution patterns running on large scale power-aware clusters. Our analytical model can help users explore the effects of machine and application dependent characteristics on system energy efficiency and isolate efficient ways to scale system parameters (e.g. processor count, CPU power/frequency, workload size and network bandwidth) to balance energy use and performance. We derive our iso-energy-efficiency model and apply it to the NAS Parallel Benchmarks on two power-aware clusters. Our results indicate that the model accurately predicts total system energy consumption within 5% error on average for parallel applications with various execution and communication patterns. We demonstrate effective use of the model for various application contexts and in scalability decision-making