Energy efficiency of software systems has been investigated by the Software Engineering research community along different aspects. For example, conceptual frameworks and guidelines have been defined to help increase stakeholders' awareness about energy efficiency; design patterns and tactics have been proposed to guide software system architects when evaluating possible alternative solutions; and techniques for collecting energy consumption data while the software is running have been developed. Research on practical methods and tools at support of requirements engineering for the development of software that meets energy efficiency requirements is still limited. In this research preview, we introduce an approach that exploits goal-oriented requirements models and software testing to explore critical scenarios for energy consumption, and identify model factors that may recur when energy consumption is greater, we call them "model indicators" of energy consumption. Techniques for performing energy consumption measurements of running software are used. The resulting method connects artefacts at requirements and run-time levels. The identified model indicators can contribute to the prediction of energy consumption of software at requirements level, thus increasing energy awareness of the analysts and developers, and support them to take more energy-friendly decisions during software development and evolution. We describe this method with the help of an illustrative example. Next steps in the proposed research are presented.