Is software "green"? Application development environments and energy efficiency in open source applications

Context: The energy efficiency of IT systems, also referred to as Green IT, is attracting more and more attention. While several researchers have focused on the energy efficiency of hardware and embedded systems, the role of application software in IT energy consumption still needs investigation. Objective: This paper aims to define a methodology for measuring software energy efficiency and to understand the consequences of abstraction layers and application development environments for the energy efficiency of software applications. Method: We first develop a measure of energy efficiency that is appropriate for software applications. We then examine how the use of application development environments relates to this measure of energy efficiency for a sample of 63 open source software applications. Results: Our findings indicate that a greater use of application development environments - specifically, frameworks and external libraries - is more detrimental in terms of energy efficiency for larger applications than for smaller applications. We also find that different functional application types have distinctly different levels of energy efficiency, with text and image editing and gaming applications being the most energy inefficient due to their intense use of the processor. Conclusion: We conclude that different designs can have a significant impact on the energy efficiency of software applications. We have related the use of software application development environments to software energy efficiency suggesting that there may be a trade-off between development efficiency and energy efficiency. We propose new research to further investigate this topic. (C) 2011 Elsevier B.V. All rights reserved.