Marco Beccali, Maurizio Cellura, Vincenzo D’Alberti. DREAM Dipartimento di Ricerche
Energetiche ed Ambientali Universita di Palermo;

Viale delle Scienze, edif.9-90128 PALERMO ITALY
Tel.+39+091236141; Fax. +39+091484425; marco. beccali@dream. unipa. it
Pietro Columba; DESAF Dipartimento di Economia dei Sistemi Agro-Forestali. Universita

di Palermo.

ABSTRACT

A Geographical Information System (GIS) supported methodology has been defined and adopted in order to assess the real technical and economical potential of biomass for energy production in Sicily contest. This methodology is based on a data referred to a (GIS) collecting data about cover land use, transport facilities, urban cartography, regional territorial planning, terrain digital model, lithology, climatic types, civil and industry users. By means of that GIS was possible to highlight the potential areas where gather the residues coming from pruning of olives, vineyards and other agricultures crops and to assess the tons of biomass available for energy purpose. The economic availability has been assessed assuming a price of the biomass comparing it with other fuels and the evaluation carried out shows the strong competitiveness of firewood in comparison with the traditional fossil fuels when the collection system is implemented in efficient way. At the same time the study has shown a good competitiveness of the finished biomasses (pellets), and good potentiality for a long term development of this market. According to these, as important result of the study is to show the opportunities stemming from the harmonisation of Energy Policy with the Waste Management System.

Introduction.

In the last decade there has been a renewed interest toward the use of Agro-Forest Biomass (A. F.B.) for energy production both at political and users level.

Therefore, research efforts have been directed to the study of possibility and consequences of using A. F.B. for energy production.

The purpose of this study is to describe a methodology able to assess the real technical and economical potential of biomass in Sicily.

The main sector where it is possible the introduction of such resources, is represented by the residential one, in particular for domestic heating systems.

The analysis were oriented also, to the possibility of biomasses exploitation potentially used as fuel in power plants for electricity generation or in central heating plants. While the fuel required in small direct combustion systems can be of various typology, quality and dimension (wood chip, pellets, olive husk), for power application fuels with rather homogeneous physical and chemical characteristics are required. So as a matter of fact, biomasses have to be conditioned through various processes such as chipping, slash chopping or cutting, and, if necessary cleaned from extraneous matter (soil, iron material, etc.) and dried.

In addition fuel which is homogeneous in size and typology represents an
enormous advantage for handling operations, storage in silos and fuelling
operations of the systems. Anyway these needs can easily be met by introducing

intermediate processing operations, such as chipping and desiccation, to be carried out before the storage at the combustion plant. The introduction of these further operations determines an increase in the operating costs with consequent higher risk for the investment.

Consequently the study proceeded to analyse the typologies of fuel obtainable from the different productive sectors, considering both characteristics of the raw matter and the presence of competing markets (conventional fuel) that could invalidate the availability of certain green resources.

Resources

The main sectors that can provide biomass for energy users are:

□ Forest harvesting;

□ Short Rotation forestry;

□ Agricultural sector;

□ Food and wood industries

□ Zootechnic sector;

Each sector will provide different typologies of biomasses with different physical and chemical characteristics.

Simply on the basis of the evaluation of physical characteristics, woody and cellulosic products of the above mentioned, activity can be classified in three broad categories of raw matter:

□ directly usable

□ usable after been subjected to a homogenisation process

□ usable after been subjected to a homogenisation process and used in plants provided with an exhaust air treatment system.

Analysing the wood-cellulosic biomasses obtainable from the agricultural sector, it can noticed, (see figure 1), that the products are mainly represented by residues coming from the activities of annual and periodical maintenance of agricultural tree crops. These are constituted mainly by branchwood coming from pruning operations, which are not marketable and are occasionally used to heat houses within the farm.

The raw matter obtained from agricultural tree crops should be processed (chipped or lopped) when the material is loaded, for example with an industrial bio-triturator.

These kinds of products have characteristic similar to Short Rotation Forest crops. Such forest crops are yet in an experimental phase, but potentially they might be able to take the place of many of the present marginal agricultural crops, improving the development perspectives in various agricultural areas. Forest harvesting has a relevant utilization in same areas of the Region.

Regarding by-products of wood and food industries they are usually used directly in the industry same process and zootechnic sector in Sicily is little relevant. For there reasons, in these two last sectors, the investigation has not been focused in this study.

Figure 1: The agricultural sector for biomass production.

The methodology adopted, in order to asses the quantity and the distribution of these potential recourses, is based on the creation of a Geographical Information System. The GIS was implemented by acquirement of a database containing information about: Corine land cover land use map, Regional cartography, administrative boundaries, populated areas, road network, Terrain digital model, lithological map, climatic types, Industry and civil census.

By mean essentially of the land cover map was possible to highlight the potential areas where gather the residues coming from pruning of olives, vineyards and other crops as well as for forest harvesting and potential SRF areas. Assuming a coefficient of productivity, inserted in the GIS, in term of biomass for hectares has been possible to assess the tons of biomass available for energy purpose. This was the first theoretical, assessment of the available resources.

Wood residues from agricultural tree crops

According to the crop system present in Sicily, we considered the following crops:

□ Vineyards pruning

□ Olive trees pruning

□ Fruit trees pruning

□ Poplar trees pruning

□ Citrus crop pruning

In order to assess the quantity of the fuel coming from these crops there was necessary to highlight by means of the Corine Land Cover map the area where the biomass is produced. Assuming a coefficient of productivity of 2 t/ha for the vineyards and fruit trees and one of 1,8 t/ha for olive and citrus crops was possible to calculate the quantity of the theoretical potential. From the assessment were excluded all the areas with a slope major than 70% and with arid climate.

These biomasses, which generally were burnt near the plots may be removed and reduced into chips for energy purposes. For this purpose in the region are present 144.125 ha of vineyards and 167.727 ha of olive crop. These represent the main economic sectors from which it is possible to obtain wood residues available for energy uses. The potential, that could be gathered in Sicily from this sector had been assessed into over 1.000.000 of ton each year.