Our research goal is to design systematic, inexpensive methods to optimize the application SW for reducing the energy consumed per useful work done, thus increasing the energy efficiency. We observe that in HPC software, communication and data sharing among the threads of an application are critical factors affecting performance and energy. Therefore, we specifically target analyzing and optimizing these aspects. We plan to demonstrate proof-of-concept of the proposed techniques using parallel benchmarks and a real-life HPC application, Molecular Dynamics (MD).