By Rui António Rua, Research Assistant at the High-Assurance Software Laboratory (HASLab)
In today’s world, technology has become an integral part of everyone’s lives. From smartphones to laptops, software has made our lives easier and more efficient. However, the Information and Communication Technology (ICT) sector is responsible for up to 10% of the world’s total energy consumption, and its footprint is expected to increase by at least 50% until 2030 [1]. The growth and impact of this sector have led to the emergence of new initiatives and research areas, such as the Green Software, whose popularity has proliferated in recent years. This area focuses on analysing the energy consumption of software and understanding how to code energy-efficient software; the main contribution of said analyses is a set of recommended practices for using software more efficiently. These recommendations can have different targets, such as users, software developers, or even operating systems and platforms.
But why is it important to build energy-efficient software? The most obvious advantage is the reduction of energy consumption, thus helping to mitigate the environmental impact of technology. Additionally, energy-efficient software can lead to cost savings for both individuals and organisations. By reducing the amount of energy needed to power computers, it’s possible to reduce electricity bills. For mobile device users, it can also improve portability by extending device uptime and battery life. As to the organisations, reducing energy consumption can lead to lower operating costs and a reduced environmental footprint.
A simple analogy to understand how software optimisations can impact energy consumption is to compare software execution with driving a car. By thinking of software as a driver and hardware as a car, we can draw parallels between driving efficiently and writing energy-efficient software. Just like drivers, who can control their cars’ fuel consumption by driving efficiently, software developers can control the energy consumption of their software by writing energy-efficient code. For example, we can perceive the CPU as the computer’s engine; and, just like how a car’s engine uses fuel, the CPU uses energy. By optimising the usage of the CPU through features like intelligent task scheduling or using efficient computing algorithms, software can reduce energy consumption and improve efficiency. Other simple analogies can be made: for instance, network access can be compared to other fuel-consuming tasks, and software can save energy through the use of power-saving modes and intelligent bandwidth management. Think of it as a truck driver who optimises trunk space to reduce weight or save trips – software can optimise the use of memory and storage by implementing features like memory compression.
Furthermore, writing energy-efficient software is not just about reducing energy consumption; it can also improve the overall user experience. Just like a car with a more efficient engine may have better performance, energy-efficient software can lead to faster load times and better responsiveness.
This new area of research has produced results with concrete scientific impact, while fostering the development of communities themselves. Numerous studies have emerged in recent years showing that significant energy gains can be obtained using migrating programming languages, architectural components, libraries, or auxiliary software such as virtual keyboards. Millions of software artefacts can reuse this knowledge to improve their energy efficiency. Even if the overall efficiency improvements are minimal, this improvement propagated by millions of executions by users worldwide (e.g., in a popular mobile application) can help to save significant amounts of energy and progressively drive us to reduce our environmental footprint.
In conclusion, the Green Software area is a crucial field of study in today’s technology-driven world. By reducing energy consumption, energy-efficient software can mitigate the environmental impact of technology, lead to cost savings for individuals and organisations, and improve the overall user experience. Analogies between driving efficiently and writing energy-efficient software can be used to better understand the importance of this field. Writing energy-efficient software is not only about reducing energy consumption, but also about improving overall performance and end-user satisfaction, making it a win-win situation for everyone involved.
[1] “Lean ICT: Towards Digital Sobriety”, The Shift Project, July 2019.
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