As large scale distributed systems gather and share more and more computing nodes and storage resources, their energy consumption is exponentially increasing. Next generation computing and data centers might require tens of MWatts to be feasible. Thus designing more efficient systems is a major challenge for computer engineers. This challenge is two-folds: saving money and being ecological by using renewable energy. The goal of this panel is to discuss current trends in energy use and energy costs of data centers and servers, metrics to benchmark computing and data centers energy consumption, and opportunities for reducing those costs through improved hardware and software.