In sheet metal forming processes there is still a lack of knowledge in the field of environmental sustainability mainly due to the need of a proper modeling of issues and factors to be taken into account. Such topic is, nowadays, a urgent and remarkable issue in manufacturing and the main concerns are related to more efficient use of materials and energy. What is more, the estimation of environmental burdens of forming technologies is very complex to be accomplished since it is essentially process-dependent. This means that when comparing, for instance, a traditional forming process with an innovative one, there are some peculiar aspects to be considered; actually, processes can be rather different each other in terms of tooling, operative parameters and so on. In this paper, a first modeling effort is presented in order to compare, from a sustainability point of view, a classical stamping process with an incremental forming one. In particular, a frustum of pyramid part is considered and a quantitative analysis of the process energy consumption was developed. The paper aims to provide some sustainability guidelines to promote discussion on limitations, advantages, savings, drawbacks offered by different technologies within sheet metal forming field.