PhD candidate Erik Jagroep developed a smart energy meter for software: a dashboard that indicates how much energy the software uses and where it can be improved. The ICT industry is a major consumer of energy, and the awareness of that is growing slowly. “Ten to fifteen percent of the entire Amsterdam energy bill comes from data centers,” explains Jagroep. “People are really not aware of the amount of energy that software uses. To name another example, the entire Bitcoin system uses as much energy as Croatia.” Jagroep defends his PhD thesis on 18 September. He worked on his PhD research part-time, in addition to his job as a consultant at Centric.

Jagroep discovered that up to two-thirds of the energy use of computers depends on the efficiency of the software that runs on it. Consequently, energy consumption of software is immensely important, but also lacks transparency, which makes it a complex problem. Therefore, he developed a method to objectively compare different versions and configurations of software applications, by calculating a resource utilization score based on energy measurements and performance aspects.

Smarter software writing

How do you actually make software more sustainable? “In one case, we managed to make a piece of software 60% more energy efficient by rewriting it in a smarter way,” Jagroep explains. “And it became faster as well. But usually it is a trade-off between speed and energy consumption.” The wishes and requirements of the end users of the software also play a role. “Sustainability is becoming more and more important. And energy efficient software can, for example, also make your smartphone battery last longer. An important question could be: how much of a problem is it if the software is a bit slower? Of course, that depends on the purpose of the software.”

Awareness

Jagroep also wanted to make software producers more aware of the energy consumption of their software. By quantifying and presenting the energy use of software with an energy profiling method, he already ignited vivid discussions on the subject. It is only a matter of time, he predicts, before software producers take energy use into account when planning future developments. “Energy use of software is already becoming increasingly important,” he says. “An update from Firefox allows for a massive saving in energy consumption. For every four million users, such an update can save as much energy every hour as an American household uses in a month.”