The amount of data moved over the Internet per year has already exceeded the Exabyte scale and soon will hit the Zettabyte range. To support this massive amount of data movement across the globe, the networking infrastructure as well as the source and destination nodes consume immense amount of electric power, with an estimated cost measured in billions of dollars. Although considerable amount of research has been done on power management techniques for the networking infrastructure, there has not been much prior work focusing on energy-aware data transfer algorithms for minimizing the power consumed at the end-systems. We introduce novel data transfer algorithms which aim to achieve high data transfer throughput while keeping the energy consumption during the transfers at the minimal levels. Our experimental results show that our energy-aware data transfer algorithms can achieve up to 50% energy savings with the same or higher level of data transfer throughput.