Understanding Green Software Development: A Conceptual Framework The energy efficiency of IT has become one of the hottest topics in the last few years. The problem has been typically addressed by hardware manufacturers and designers, but recently the attention of industry and academia has shifted to the role of software for IT sustainability. Writing energy-efficientsoftware is one of the most challenging issues in this area, because it requires not only a change of mindset for software developers and designers but also models and tools to measure and reduce the effect of software on the energy consumption of the underlying hardware. In this article, the authors present a conceptual framework that provides a unifying view of the strategies, models, and tools available so far for designing and developing greener software.