Olive oil is one of the most renowned food products of Europe’s Mediterranean countries. The European Union is both the leading producer and consumer of olive oil in the world, accounting for more than 80% and 70% of the production and consumption respectively. Olive groves are also one of the most iconic features of Mediterranean landscapes, extending over a total area of around 4.65 million ha in the EU in 2012, mainly in Spain (53%), Italy (24%), Greece (15%) and Portugal (7%). A lesser known fact, however, is the enormous amount of biomass potential generated through the pruning operations of the olive trees.
While the biomass is highly variable with productivity values ranging from 0.4 t/ha to more than 11t/ha of dry biomass (depending on the type of biomass and pruning practices), the biomass potential is hardly exploited since the largest branches are often the only waste removed from the fields and used as firewood, while the remaining material is usually either disposed of in open-field fires or mulched on the ground. It is clear, however, that no matter how it is estimated, the European potential of this type of biomass resource is huge.
The agro-industrial residues generated by the production of olive oil are also important. The average oil content of an olive fruit is 20%. In 2015, the annual production of olives for oil processing was 10.4 million tons, therefore more than 8 million tons of olive pressing residues were produced by olive mills; these materials are usually further processed by secondary mills – known as pomace mills – to produce residual oil fractions and solid by-products which are typically used as solid biofuels in various applications.
The olive oil sector faces challenges similar to those of other agro-industries around Europe: seasonal operation, idle time of specialised equipment and other capacities. On the other hand, having a central role in agricultural areas, they can naturally evolve to the next phase of operation, e.g. their transformation into Integrated Biomass Logistic Centres (IBLCs for short). An IBLC is defined as a business strategy for agro-industries to take advantage of unexploited synergies in terms of facilities, equipment and staff capacities, to diversify regular activity both on the input (biomass feedstock) and output side (biocommodities & intermediate biobased feedstocks). IBLCs thereby enhance the strength of agro-industries and increase the added value delivered by those companies.
The “AGROinLOG” project (funded from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No 727961) aims to demonstrate the IBLC concept in three agro-industries (cereal processing, animal feedstock and olive oil processing) around Europe and to replicate the concept in other agro-industrial sectors. The olive oil sector demonstration is based around one of the leading companies in the sector in Greece, NUTRIA S.A. and is supported by the Centre for Research and Technology Hellas (CERTH) and the Institute of Agricultural Cooperative Economy (INASO-PASEGES).
The demonstration aspects of the project foresee the mechanised harvesting of olive tree prunings in the area of Agios Konstantinos in Central Greece, where NUTRIA is located. The harvested, chipped biomass can lose its residual moisture through treatment at the rotary dryers of pomace milling facilities, and then is either sold on the market as dried chips or further processed and turned into pellets via an additional line. The validation of the solid biofuels produced will be performed through combustion tests in commercial boilers or specialised laboratories. Considering the local availability of olive tree prunings, it is estimated that up to 8,000 tons of upgraded biomass fuel can be brought into the market on a yearly basis.
Additionally, the project activities will consider the cases of bio-commodities production from olive tree prunings, in particularly particleboards, as well as the separation of valuable phenolic compounds from the various residual streams (olive pomace, olive leaves) that an agro-industry operating in the olive oil sector can source.
Overall, the application of the IBLC concept to a Greek olive oil industry is expected to widen its business orientations, increasing its annual turnover, while also promoting the concepts of circular economy and sustainable rural development.
More detailed information can be found on the AGROinLOG project website: http://agroinlog-h2020.eu/en/home/