Spanish mainland crops, including olives, almonds, and pistachios, play a pivotal role in capital circulation and employment generation. This comprehensive study explores the economic feasibility on the utilization of diverse agro-industrial wastes from Spanish harvests as a promising feedstock for bioenergy production through fast pyrolysis. The fast pyrolysis process is simulated using Aspen Plus® software, employing techno-economic parameters such as Net Present Value (NPV), Internal Rate of Return (IRR), Payback Period (PBP), break-even, and minimum product sales price to analyze economic viability of the project. Two different scenarios, based on experimental data from previous studies, are compared. The profitability of this proposal is closely linked to the harvest, which serves as a limiting factor. In all scenarios, the project requires two years to recover the initial investment, demonstrating significant profits once production begins. When considering the impact of scaling up, the NPV of Scenario 2 for PS reached €369.55 M€. Sensitivity analysis reveals that the profitability of pyrolysis depends on the bio-oil selling price and the total production volume. Overall, this study confirms the economic viability of producing bioenergy through fast pyrolysis using various biomass residues. It highlights the potential of harnessing bioenergy from Spanish agro-industrial waste, paving the way for sustainable and economically viable solutions, as indicated by the NPV and IRR metrics.