Cloud computing has become an attractive and easy-to-use solution for users who want to externalize the run of their applications. However, data centers hosting cloud systems consume enormous amounts of energy. Reducing this consumption becomes an urgent challenge with the rapid growth of cloud utilization. In this paper, we explore a way for energy-aware HPC cloud users to reduce their footprint on cloud infrastructures by reducing the size of the virtual resources they are asking for. We study the influence of green users on the system energy consumption and compare it with the consumption of more aggressive users in terms of resource utilization. We found that larger resources are more energy demanding even if they are faster in executing the applications. But, reducing too much the resources' size is also not beneficial for the energy consumption. A tradeoff lies in between these two options.