Solid biomass planning is a complex and multifaceted process, as it aims to achieve a large number of objectives while involving various stakeholders. This complexity heightens particularly in marginal areas, where socioeconomic weaknesses are critical obstacles to the sustainable development of these territories. This paper proposes an integrated method for dealing with such problem by using a combined optimization approach. This is done in order to implement the ‘best’ investment solution to be realized in marginal areas, and a benefit cost analysis to assess the feasibility of investment for each involved operator. The methodology of the study maximizes the utility of the stakeholders in the respect of the territory. The effectiveness of the proposed approach has been demonstrated through a twofold and comparative application, both in Italy and in Germany, in order to verify the results.