The conversion of residues into energy presents an advanced and sustainable solution for waste management, a dual objective being hypothetically met: a waste management solution is offered while sustainable energy is produced. One of the methods to achieve that is through gasification, which provides a multipurpose synthetic gas (syngas), showing high efficiencies and cleaner conversion processes when compared to other techniques. This study is included in a framework to explore the conversion of various agroforestry residues (miscanthus, vine pruning, Pinus pinaster and wood chips) into syngas to enable the calculation of the related quality index, a crucial parameter to assess syngas quality and recommend potential applications. These endorsements can guide not only the optimization of gasification strategies towards the accomplishment of a dedicated syngas quality level, as well as support policymakers and industry stakeholders to implement effective and productive waste management practices. In this research, Portuguese feedstock samples were characterized and their gasification was modelled to evaluate the influence of some experimental parameters over the calorific content of the syngas produced to suggest its further use.