Agricultural residues as biomass energy

An evaluation of the production of agricultural residues in Turkey and their conversion to electrical energy via gasification was realized. Agricultural residues were classified into two main categories. The residues in the category A were separated into two sub groups. The residues in the subgroup A1 generally consisted of straw, plant stems, and leaves while the subgroup A2 consisted of pruning residues of fruit trees. Nearly 43 mt/yr residues are produced in category A, or dry basis. As to the subcategories, 10.8 mt/yr residues are produced in the subcategory A1 on dry basis, since 28% of the residues in this category are not utilized; approximately 3.2 mt/yr residues are produced in the subcategory A2, since 80% of the pruning residues in this category are not utilized. The processed product residues in the category B were classified into three subcategories. The subcategory B1 comprises the residues in oil production (i.e., stone, shell), the subcategory B2 comprises the residues resulting from fruit processing (i.e., stalk, peel, stone), whereas the subcategory B3 consists of the residues such as peel, seed, and husk (in tomato and rice). The highest residue quantity in the subcategory B1 was in sunflower in the form of shell with 157.6 thousand tons, the highest residue quantity in B2 subcategory was in grape with 423.0 thousand tons (in the forms of stalk, peel, and stone); in subcategory B3, the highest residue quantity was in tomato (in the forms of peel and seed) with 134.0 thousand tons. Nearly 17% of the national electricity consumption can be met if all of the unused residues (15.3 mt/yr) are converted into energy. One may say that the regions Marmara, Mediterranean, Aegean, and Central South are the suitable regions for electricity, since these are the agricultural regions having the highest intensity of unusable agricultural residues (28.0-43.2 t/km(2)).