Achim Guldner

Sustainable software products—Towards assessment criteria for resource and energy efficiency

Many authors have proposed criteria to assess the “environmental friendliness” or “sustainability” of software products. However, a causal model that links observable properties of a software product to conditions of it being green or (more general) sustainable is still missing. Such a causal model is necessary because software products are intangible goods and, as such, only have indirect effects on the physical world. In particular, software products are not subject to any wear and tear, they can be copied without great effort, and generate no waste or emissions when being disposed of. Viewed in isolation, software seems to be a perfectly sustainable type of product. In real life, however, software products with the same or similar functionality can differ substantially in the burden they place on natural resources, especially if the sequence of released versions and resulting hardware obsolescence is taken into account. In this article, we present a model describing the causal chains from software products to their impacts on natural resources, including energy sources, from a life-cycle perspective. We focus on (i) the demands of software for hardware capacities (local, remote, and in the connecting network) and the resulting hardware energy demand, (ii) the expectations of users regarding such demands and how these affect hardware operating life, and (iii) the autonomy of users in managing their software use with regard to resource efficiency. We propose a hierarchical set of criteria and indicators to assess these impacts. We demonstrate the application of this set of criteria, including the definition of standard usage scenarios for chosen categories of software products. We further discuss the practicability of this type of assessment, its acceptability for several stakeholders and potential consequences for the eco-labeling of software products and sustainable software design.

High frequency non-intrusive electric device detection and diagnosis

The number of electronic devices in households as well as in industrial workplaces is continuously growing because of progress in automation. Identifying unusual operating behavior, detecting device failures in advance, and recognizing energy saving potentials are key features to improve the reliability, safety, and profitability of those systems. Facing these tasks, todays research is focused inter alia on a non-intrusive load monitoring approach, where the electrical signal is measured at a central point with modern hardware and processed by pattern recognition algorithms. Thus, we developed a smart meter prototype with a high sampling frequency, which allows for continuous measurement of the current and voltage from three-phase power lines. Besides this, in this paper we describe the usage of current-only measurement data (simple and safe installation using current transformers) with which we were able to classify state changes of a mobile air-conditioner with the help of Fourier descriptors as well as with additional voltage measurement.

Including Software Aspects in Green IT: How to Create Awareness for Green Software Issues

While counteracting the increasing demand for natural resources and especially energy of ICT, first successes have become apparent by activities comprised by the term “Green IT”. Nowadays, many of the current activities lay emphasis on the hardware side of Green IT. However, software issues play a significant role in defining system and hardware requirements as well as the amount of energy consumed by ICT devices and the underlying infrastructure. Thus, the following chapter introduces the idea of green software and its engineering. Complementary to definitions and models in the addressed field, a more practical insight is given by illustrating exemplary energy measurements of software products. While these aspects show that the research is increasingly dealing with software issues of Green IT, these mainly scientific ideas have hardly reached practical relevance, so far. Hence, following the life cycle perspective of software products, we present two exemplary concepts on how to increase awareness of green software: addressing especially software engineers, we propose to implement continuous energy efficiency measurements during the development phase. With regards to software users, we propose to create an eco-label for software products to inform about their environmental issues and thus create more transparency in this context. To do so, we present and evaluate criteria and indicators, upon which a label could be based. The chapter concludes with a summary and proposes future activities in the addressed field. Overall, the aim of the chapter is to point out solutions that might lead to a more environmentally friendly way of developing software, a well-informed procurement behavior regarding software products, and a more sustainable user behavior concerning ICT.

Bewertung der Nachhaltigkeit von Software: Entwicklung einer Umweltkennzeichnung

In diesem Beitrag werden Ansatze zur Entwicklung eines Labels fur grune und nachhaltige Software vorgestellt. Wahrend fur den Bereich der Hardware bereits zahlreiche Labels wie ENERGY STAR, TCO oder auch Produktkategorien des „Blauen Engel“ existieren, liegen fur den Softwarebereich bisher erst einzelne Kriterien und Untersuchungsergebnisse vor, die aber noch nicht zu einem veroffentlichten Label zusammengefasst sind. Basierend auf den Kriterien fur Hardware sowie einer Umfrage werden daher Uberlegungen entwickelt und uberpruft, welche den Bereich der Nachhaltigkeit von Software in den Fokus nehmen. Da umweltbezogene Kennzeichnungen auch im betrieblichen Kontext eine wichtige Rolle zur Erreichung von Nachhaltigkeitszielen spielen, sehen wir durch diese Kriterienentwicklung einen Beitrag zur Verbesserung der Ressourceneffizienz von IKT, der sich auch auf die Anwendungsdomanen von Software ubertragen lasst. Eine von uns durchgefuhrte Umfrage bestatigt diese Bedarfe insbesondere hinsichtlich Energie- und Hardwareeffizienz.

Energy Consumption and Hardware Utilization of Standard Software: Methods and Measurements for Software Sustainability

The ubiquity of information and communication technologies (ICT) results in substantial amounts of energy consumption and thus, CO2-emissions. Since software induces the energy consumption of hardware, some reliable procedures and tests for measuring software are necessary. We present such a method and prove our measurement concept by applying it to two software product groups: word processors and content management systems. Even though the two groups are very different in terms of their requirements, we were successful in the creation of a measurement environment that supports the production of reliable, verifiable results, allowing the comparison of the energy consumption induced by software systems with similar functionality. The method shows viable results for desktop and client-server systems, paving the way for further setups like e.g. mobile and embedded devices.