Chapter 17 - Environmental sustainability in energy production systems

Abstract

Sustainable energy supply is one of the main challenges’ humanity will face in the coming decades, particularly due to the need to address global warming. In this sense, producing energy from the valorisation of agricultural, forest, and agro-food residues plays a key role, while helps to reach the EU targets. In this chapter, the environmental sustainability linked to the production of bioenergy from pruning and forest residues was deeply evaluated considering the Life Cycle Assessment (LCA) methodology. Although a standardised framework regulates the procedure, its application in practice poses some methodological difficulties. Therefore this chapter considers the main methodological issues that a LCA practitioner must face when it comes to the environmental assessment of bioenergy systems. Two case studies were considered for assessment from an attributional cradle-to-energy factory gate approach. The first case study addresses the environmental impact of bioenergy (heat and electricity) production in medium size plants using forestry residues as feedstock. The conversion of biomass into energy takes place in a CHP plant (1MW of electric power) and 1 kWh of electricity fed into the grid was selected as functional unit. The second case study focuses on a smaller bioenergy plant fed agricultural residues and, in more detail, with pruning residues from vineyard. Here, besides a baseline scenario where the pruning residues are left into the soil and the energy required for winemaking is supplied using fossil energy two alternative scenarios were considered. The thermal energy produced by the combustion of the chopped pruning residues is used to meet the head demand of winemaking. In both the case studies, the environmental hotspots were identified as well as future research activities were proposed with the aim of improving the sustainability of the analysed bioenergy pathways.