1. Introduction Biomass from agro-forestry and agro-industrial residues can play a key role in achieving targets for fossil-fuel substitution. Olive tree pruning practices and olive oil extraction processes produce large amounts of residues. Olive growing involves 47% of Italian farms and covers 8% of the overall Utilized Agricultural Area. Apulia concentrates 22% of farms and 31% of total Italian area under olives [Istat 2000a] and is the main olive and olive oil producer in Italy. The aim of this study is to review the olive-chain residues sector, estimate the energy potentials of the olive-oil chain residues in the Apulia region, namely pruning residues (PR) and crude olive husk (COH), and assess the collection costs with different supply chain scenarios. 2. Overview of the olive-chain residues 2.1 Olive tree pruning residues Olive tree pruning residues are a considerable source of biomass. They can be distinguished into wood (branches with a diameter of more than 40 mm), shoots (branches with a diameter of less than 40 mm) and leafy branches (small braches and leaves) [Ami- rante 2002; Spinelli 2000; Jimenez 2002]. Except for wood, which is still widely used as fuelwood, mostly in rural areas, shoots and leafy branches are very often not collected and recovered, because of their low value. For this reason, in this paper PR are represented only by shoots and leafy branches. On average, each olive tree produces 10 – 30 kg/year of PR, depending on the structure and size of trees. Only in few cases pruning residues are used as animal feed. They are generally stacked and burnt on the field. Nowadays, with the im- plementation of alternative anti pathogen methods (which limit pathology diffusion caused by shoots and leafy branches left on the soil), pruning residues are sometimes chipped and ploughed in to provide plant nutrients. A ton of PR with a moisture content of 50% w.b. releases about 4 kg of N, 0,5 kg of P, 0,5 kg of K, 5 kg of Ca and 1 kg of Mg. In most cases, however, the cost of this operation is not balanced by the increment in plant yield [Amirante 2002]. As a consequence, it should be more efficient to recover these residues and use them for energy purposes. An appropriate mecha- nization and rationalization of pruning residues collec- tion, package and transport operations could enhance their use for energy purposes. The most relevant properties of PR, in view of their energy use, are Lower Heating Value (LHV), moisture content, ash content and size. Moisture content and size depend on the collection and treatment tech- niques, while ash content and LHV depend on physi- cal and chemical characteristics. In particular moisture content depends on plant’s age, collection time, collec- tion and storage conditions, both on field and at dedi- cated facilities. On average, leafy branches have a moisture content at collection time of 50% d.b., a C-N ratio of 33% d.b. [Amirante 2002]. 2.2 Olive husk and olive mill wastewater Another relevant source of biomass, suitable for energy purposes, is the olive oil extraction process. It is a widely implemented agro-industrial activity which has a huge relevance for the economy of Mediterranean Countries, that are responsible for 99% of the annual worldwide production of olive oil (about 2.7 million tons/year) [ISMEA 2003]. The main by- products of the olive oil mills are the olive mill waste- water (OMW) and the crude olive husk (COH) (or crude olive cake). Every year Mediterranean Coun- tries produce about 30 million m 3 of OMW and 20 J. of Ag. Eng. - Riv. di Ing. Agr. (2009), 1, 37-47 OLIVE RESIDUES TO ENERGY CHAINS IN THE APULIA REGION PART I: BIOMASS POTENTIALS AND COSTS Antonio Pantaleo, Maria Teresa Carone, Achille Pellerano ___________ Paper received 09.07.2008; accepted 13.01.2009 Corresponding author: Ing. ANTONIO PANTALEO, a.pantaleo@agr. uniba.it. University of Bari, Department of Engineering and Manage- ment of the Agricultural, Livestock and Forest Systems Via Amendola 165/A 70125 BARI (Italy). The contribution to the research set up and execution should be equally subdivided among the Authors. 006_Pantaleo(537)_37 27-07-2009 11:20 Pagina 37