October 2014 Theme: Green IT and Green Software
Guest Editors' Introduction: Ayse Basar Bener, Maurizio Morisio, Andriy Miranskyy, and Sedef Akinli Kocak

Rising energy demands and the growing negative environmental impact from the increased adoption of IT services are motivating the green movement in IT, which places great importance on the design and implementation of green solutions. Green IT is applicable to a range of high-tech domains, including datacenters, mobile computing, and embedded systems. Annual global carbon dioxide emissions recently reached 9.1 billion tons, the highest level in human history — 49 percent higher than in 1990 (the Kyoto reference year).[1] At least 2 percent of global carbon dioxide emissions can be attributed to IT systems, and further increases are expected as new IT systems are deployed daily. Reducing IT systems’ energy consumption and related carbon dioxide emissions is a vital undertaking.

The Problem

Most studies and regulatory controls focus on hardware-related measurement, analysis, and control for energy consumption. However, all forms of hardware systems are controlled by software components. Although software systems don’t consume energy directly, they affect hardware utilization, leading to indirect energy consumption. Therefore, it’s important to engineer software so that its energy consumption is optimized. The software engineering research domain has recently been paying attention to sustainability, as the increased number of publications, empirical studies, and conferences on the topic demonstrate.

Green IT aims for minimal environmental impact from the design, production, and use of computers, servers, monitors, printers, storage devices, and networking and communications systems. It focuses on product and process efficiency, in terms of environmental sustainability, as well as applying IT to create energy-efficient, environmentally sustainable business processes and practices. IT can support, assist, and leverage other environmental initiatives and help in creating green awareness.

Like green IT generally, greening in software seeks to reduce the environmental impact of the software itself. Greenness is thus an emerging software quality attribute to consider, as well. Software companies are beginning to confront the conflict between being as environmentally friendly as possible and customer pressure for new functional requirements and high quality. Yet, software systems can also play a proactive role in saving energy by providing feedback about the way they consume resources and, ideally, leading people to change behaviors and create greener processes.

In This Issue

Computing Now’s October theme presents six articles that focus on the various aspects of software engineering in green IT and green software including requirements, design, and coding, maintenance, the software development process, and end products and the user experience. All of them seek to keep the environmental impact low by efficiently using the required resources.

In the May/June 2014 issue, IEEE Software ran a special issue on various aspects of green software. In “Safety, Security, Now Sustainability: The Nonfunctional Requirement for the 21st Century,” authors Birgit Penzenstadler and her colleagues argue that sustainability (that is, green software) is now considered a nonfunctional requirement similar to safety and security. In pursuit of their main research question — whether sustainability requirements will become as important as safety and security requirements — the authors explore parallels between these three types of nonfunctional requirements, arguing that some existing tools and techniques used for safety and security can be reused in the sustainability domain. In addition, the article highlights the importance of sustainability requirements’ indirect impact, arguing that analysts should consider not only the direct effects of requirements (such as energy consumption) but also indirect effects (such as changes in consumer behaviors).

In the same issue, Chenlei Zhang, Abram Hindle, and Daniel M. German contend that human factors must be considered as part of accurate software systems analysis. In “The Impact of User Choice on Energy Consumption,” the authors analyze the energy consumption of software applications in the same category across several usage scenarios. Perhaps not surprisingly, they find that applications have different efficiencies, and so, suggest introducing consumption ratings both to make public the efficiency of software applications and to modify user behaviors.

In “Harnessing Green IT: Principles and Practices,” IT Professional editor in chief San Murugesan examines some of the most important questions, such as:

  • What are the key environmental impacts arising from IT?
  • What are the major environmental IT issues we must address?
  • How can we make our IT infrastructure, products, services, operations, applications, and practices environmentally sound?
  • How can IT assist businesses and society at large in their efforts to improve our environmental sustainability?

Marugesan presents a holistic approach to greening IT, proposes a green IT strategy for enterprises, and outlines specific ways to minimize IT’s environmental impact. He also argues not only that IT businesses can gain a competitive edge by adopting green IT practices but also that the IT sector as a whole has a responsibility to help create a more sustainable environment.

The next article, from IT Professional’s Jan/Feb 2011 special issue on IT for a Green Planet, considers web browsing, which has been increasing dramatically due to continued growth in the use of Web-based applications, including email, social networking, blogging, streaming videos, and photo editing and sharing. We need to make Web browsing greener by reducing its power consumption. As a starting point, “Greening the Internet: Measuring Web Power Consumption,” by Aruna Prem Bianzino, Anand Kishore Raju, and Dario Rossi, evaluates the power consumption of end-user PCs browsing the Web, looking at different combinations of websites, browsers, and operating systems. The authors identify a specific area — tabbed browsing — for minimizing overall power consumption.

Most IT professionals and companies have begun to consider green and sustainable strategies to reduce energy costs and contribute to environmental sustainability. Going forward, however, they’ll need to deal with all the hardware and software requirements and the environmental impact of IT and its use. In “Enabling Green IT through Energy-Aware Software,” Manuj Sabharwal, Abhishek Agrawal, and Grace Metri present some software methodologies and designs that can be used to improve the energy efficiency of application software and middleware. The authors argue that green IT infrastructure is incomplete without energy-aware software, which plays an important role in overall IT-platform energy efficiency. The article uses multiple case studies on real-world applications to highlight ways in which application software leads to energy inefficiencies, outlining how to diagnose such problems and discussing energy-efficient software methodologies.

Although functionally richer and more flexible, newer software packages often incur larger resource overhead in typical execution scenarios, especially in rapidly developed applications with complex business logic and integration requirements. In our final theme article, Suparna Bhattacharya and colleagues realize that, coincident with the emphasis on application functionality and flexibility, there has been a declining focus on the efficient use of computing. In their study, “Software Bloat and Wasted Joules: Is Modularity a Hurdle to Green Software?,” they point out that minimizing the runtime energy expended on built-in provisional generality is critical to achieving zero-bloat (green) software, and they propose designing software, programming models, and runtime systems in a way that makes it easier to detect and mitigate such bloat.

In the near future, IT greening and the greening of systems by IT will be necessary for companies and professionals. They must understand the potentials and completely rethink current activities to address sustainability issues and support sustainable and innovative business models and processes. Feature articles such as those in this month’s CN theme, outlining new advances and current trends as well as presenting case studies that demonstrate the benefits of greening software and IT systems can help improve awareness and motivate companies and individuals to “green.” At very least, they offer a starting point to help the IT sector and users create a greener, more sustainable environment for the benefit of current and future generations.


1. G.P. Peters et al., “Rapid Growth in CO2 Emissions after the 2008-2009 Global Financial Crisis,” Nature Climate Change, vol. 2, 2012, pp. 2–4.


A. Basar Bener, M. Morisio, A. Miranskyy, and S. Akinli Kocak, “Green IT and Green Software,” Computing Now, vol. 7, no. 10, October 2014, IEEE Computer Society [online]; http://www.computer.org/publications/tech-news/computing-now/green-it-and-green-software.

Ayse Basar Bener is a professor at Ryerson University in Toronto, Canada. Her research interests include data science and analytics and green software and analytics. Bener has a PhD in information systems from London School of Economics. Contact her at ayse.bener@ryerson.ca.

Maurizio Morisio is a professor at Politecnico di Torino, Italy. His research interests include green software, Morisio has a PhD in software engineering from Politecnico di Torino. Contact him at maurizio.morisio@polito.it.

Andriy Miranskyy is an assistant professor at Ryerson University. His research interests include mitigating risk in software engineering, focusing on software quality assurance, big data, and green IT. Miranskyy has a PhD in applied mathematics from the University of Western Ontario. Contact him at avm@ryerson.ca.

Sedef Akinli Kocak is a PhD candidate at Ryerson University. Her research interests include sustainability considerations in software development and quality, green IT, and big data analytics. Kocak has a masters degree in chemical engineering from University of Maine, USA. Contact her at sedef.akinlikocak@ryerson.ca.


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Translations by Osvaldo Perez and Tiejun Huang