Agroforestry and Bioenergy: A comprehensive critical review on the strategic agroforestry system application and worldwide bioenergy power generation from 2000 to 2030

The ever growing and urgent need to be able to recognize and manage - in the best possible way - such a global imbalance in terms of management of natural resources, of environmental changes affecting globally the Earth planet (climate change, pollution by greenhouse gases (GHGs) emissions, toxic compounds, excessive consumption of fossil fuels, alteration of biodiversity balance and other factors) and the human life quality, has become one of the primary targets to be reached as soon as possible. To try responding to this urgent “Global Environmental Call”, the present study provides an analysis aimed at identifying a potential strategical route to guarantee a sustainable ratio in agriculture. The strong interest in combining Agroforestry System(s) (AFSs) with Environmental Engineering (EE) was able to trigger interesting and promising dynamics between the agricultural scope and the bioenergy’s one. Through a comprehensive review, it was possible to identify and define the main parameters coming into a play in this match, by focusing on the characterization of the biomass as the first source of such a dynamic chain of sustainability. AFSs can be considered as vectors of innovation in the environmental engineering scope because they produce biomass feedstock to be intended as a fundamental ring of the chain aimed at generating the well-known renewable energy (RE), better defined as bioenergy (BE). Such an integrative combination, if carefully managed, could face the numerous environmental challenges by providing – in the longer term – several benefits in various scopes. Focusing on the main biomass conversion processes aimed at producing bioenergy products (heat, power, and biofuels) was the engineering-based ring for better understanding and correlating the different pathways of the bioconversion from biomass to biofuels and power. The consequent quantitative analyses carried out on key energy data andstatistics about Energy Production (EP, [Mtoe]), Total Primary Energy Supply (TPES, [Mtoe]), Electricity Final Consumption (EFC, [TWh]) and Total CO2 Emissions (CO2, [Mt of CO2]) - assessed in Italy from 1990 to 2018 (with a further update until to 2019) - highlighted the energy trends to consequently be compared with the amount expressed in percentage across time from 1990. Then, analyzing the bioenergy indicator total energy supply (TES) by source, precisely by biofuels and waste – from 1990 to 2020 in Italy was useful to outline bioenergy trend in comparison to energy by fossil fuels. Finally, it was placed a focus on worldwide Bioenergy Power Generation (BPG) in the Net Zero Emissions by 2030 to include the new bioenergy paradigm. It has emerged that the European bioenergy Policy developments and sustainability governance need to boost bioenergy growth at a different scale, despite the positive approaches and developments on-going, by tracing sustainable pathways.