In the Puglia Region a circular economic model that starts from olive groves
In the framework of the Horizon 2020 programme, the project Agroinlog aims to develop models for the management of agricultural and agroindustrial residual biomass. In the context of the project, which involves a number of partner countries, the pilot experience in the city of Calimera in the province of Lecce plays a key role. It is based on the use of olive prunings and can be reproduced in any territory with the same agricultural vocation, such as Greece
The aim of the project Agroinlog (Demonstration of innovative integrated biomass logistic centres for the Agro-industry sector in Europe) is to demonstrate the feasibility of “integrated logistic centres” for an efficient management of residual biomass in different areas of the agroindustrial sector such as the production of olive oil, cereal production and fodder processing.
The project, financed by the research project Horizon 2020, is coordinated by Circe, the Spanish research centre for energy resources, and involves 15 partners in 8 countries (Holland, Spain, Greece, Sweden, Italy, Belgium, Ukraine, Serbia). Italy is represented by Crea-ing, responsible for the activities of mechanized harvesting of the residual biomass object of study. With regard to the olive oil sector, which interests the Mediterranean area in particular, Greece intends to exploit pruning of olive groves by inserting it in the productive cycle of a large olive oil factory, for the generation of the heat necessary for the functioning of the plant itself. To this end, as Vincenzo Alfano, researcher at Crea-ing, explains, “the contribution of modern operating machines plays a role of primary importance in ensuring a good level of quality of residual biomass and in containing supply costs for the energy conversion plants”.
For this purpose, the 1 MWe plant active in Calimera (LE), managed by the Fiusis company, has been identified as a model of environmental sustainability to be followed in the organization of the production chain being set up in Greece. The term Fiusis, it is worth noting, derives from the ancient Greek Physis, that literally means “nature”. This plant, besides representing a good example of integration with the territory for the energetic exploitation of olive prunings, operates in an area of the Puglia region where the climatic characteristics and the management methods of the olive groves are very similar to the Greek ones in the interested area.
Setting up the plant and launching the production chain
The initial investment in the 1 MWe cogeneration plant, which started working in 2010, was of about 8 million euros. Its realization was preceded by four years of study necessary to understand all the technological aspects of the productive process, for the financial arrangements and especially for the identification of the supply basin.
The administrator of the Fiusis plant Marcello Piccinni claims that “in the Mediterranean region the populations in Greece, Italy and Spain, although they live among forests of olive trees, have never been able to implement an efficient and well organized production chain based on the harvesting of wood. This consideration lead to the idea of exploiting this resource, and resulted in the development of Fiusis in 2010.”
This latter aspect has represented the real challenge of the project, even more than finding the necessary funding. The search for the best location for the plant lead to the identification of a basin of 9 municipalities in a 10 km area around Calimera that, thanks to the presence of about 160,000 olive trees, is sufficient to supply the plant entirely with the prunings of the trees in the area.
The full understanding of the technical aspects connected to the productive process has allowed to respond to all those who, in various contexts, were against the initiative from the start, and to overcome the bureaucratic obstacles in order to obtain the authorizations, which required to interface with about 50 different institutional bodies. Among these, however, the municipality of Calimera showed its support for the project from the beginning.
Furthermore, the technical skill and the knowledge acquired have been fundamental in providing the guarantees required by some financial institutions that have economically supported the construction of the plant, which did not benefit from any public contribution.
Also, the effort to build consensus locally was decisive especially in the first phase of the production chain; the participatory processes adopted in some biomass plants active in Tyrol, Carinthia and Bavaria served as model. These plants,some of which are located also inside human settlements, are often open to the public. In this perspective the Calimera plant has been purposely designed so that the exterior walls do not block the view to the structure from the outside.
Organization and mechanization of the chain of production
The initial decision to outsource the harvesting of the prunings to contractors was abandoned after three years because it proved economically unsustainable. A new company inside Fiusis was set up, dedicated exclusively to the field phase, equipped with machinery for the harvesting and the delivery of the product to plant. The supply plan of the company is organized so that farmers interested in supplying (with no remuneration) the prunings can do so by submitting a request directly to the plant, which involves filling in a form in which they must indicate cadastral identification, the number of pruned trees and the date of pruning. The information that is collected is then archived in a database in order to ensure the traceability of the biomass and facilitate the organization of the logistic phases of harvesting and delivery.
Thanks to the relationship of mutual trust established with local farmers, in the course of only some years the requests for the harvesting of olive grove prunings have gone from the initial 12 to the present 1,200. In return for the collection of the prunings the farmers have their fields cleaned and no longer need to resort to field burning, which is harmful for the environment and also costly. At present, thanks to the development of the chain of production, it is estimated that this practise has decreased inside the supply basin by 70%.
In firms that have up to 400 olive trees, the harvest is carried out using Facma forage harvesters, Comby model, which are able to gather 20-25 t of prunings a day (three units are used). For firms that have a higher number of olive trees, prunings are gathers at the edges of the fields and chipped with a Caravaggi shredder with a production capacity of 10t/hour. Chipping in both cases is carried out after 25-30 day period in which the prunings are left in the field to ensure drying and leaf shedding.
The harvesting period goes from January to the end of June, which coincides with the period of production pruning, carried out every three years with an output of about 10t/ha, and from September to December, when light pruning is carried out (on the trees during the year they bear no fruit). Winter harvest yields an overall production of 110 t a day with humidity at 37-38%, while autumn harvest yields 35/40 t a day with humidity at 15-16%. The overall quantity is sufficient to continually power the plant that requires 24-28 tons of prunings a day, depending on the humidity of the product. The material is stacked in small heaps in the fields where it has been gathered and is stored until the scheduled collection, organized on the basis of the requirements of the plant. This way biomass loses humidity in the fields more quickly, and the area for storage at the plant is consequently relatively small in size.
Management of biomass inside the plant
The plant is equipped with a sheltered area for the storage of the biomass; from here the chipped wood is transferred to the loading pit and inserted into the boiler through a system of rakes and conveyor belts.
This supply system allows to use chippings with irregular grain sizes that favours air permeability, speeding up natural drying in heaps, while optimizing primary combustion of the coals.
Technologies for energy conversion are entirely made in Italy (Uniconfort boiler and ORC Turboden turbine). Furthermore, thanks to the innovative filtering system, also Italian, fine particle emissions is only 1 mg/Nm3, well under the limit set at (30 mg/Nm³).
From a social point of view the production chain activated at Fiusis has created employment at a local level. On the whole, thirty workers have been employed with a permanent contract, of these six are technicians who oversee the functioning of the plant, while ten workers are organized in three teams for the collection and one for the delivery of the biomass to the plant. All the energy produced is delivered to Enel along a line that powers the city of Calimera directly, the first to be powered by renewable energy in the city of Salento, and one of the first in southern Italy.
Finally, the development of two new lines of production is scheduled, one for pallet (with the enlargement of the prunings supply basin) and one for fertilizers obtained from ash. ITABIA and the University of Foggia (partner with the twin project Up_Running) have been involved, they remain outside the project but have shown a keen interest. Both, in close contact with CREA-ING, will contribute in spreading the initiatives of the project through their communication channels; among these initiatives is the organization of a specific workshop that will be held during the Agrilevante fair dedicated to agricultural mechanization (Bari 12-15 October 2017).
