Energy crops of sunflower, soybean and rapeseed are traditionally used for the production of biodiesel, while crops of cane, sugar beet, corn and wheat are used to produce bioethanol. The production of biofuels, when it is not limited to the residual biomass from agro-food crops, is affected by an extensive use of agricultural land with possible consequences on production and prices of some essential commodities (e.g. bread, pasta).

The production of biofuels from spontaneous residual biomass (macroalgae) offers a viable alternative to traditional methods, limiting both the direct use of agricultural land and the consequent constraints of the market. In particular, the bloom of macroalgae in the two systems of Lesina (51 km2 of surface and average depth of 0.7 m) and Orbetello (25.25 km2 of surface and average depth of 1m) lagoons is the result of an intense process of eutrophication, conditioned by the presence of fish farms and aquaculture. This natural process, accelerated by human activities, requires a systematic collection of algal biomass with dynamic and, often, very challenging costs (i.e., fuel consumption for the systematic collection, biomass disposal in the form of special waste).

The requirement of the project BALLO is that collected macroalgae might represent a potential resource, not adequately exploited yet, for the biofuels production. Ecodynamics Group has developed a sustainability assessment-feasibility of the proposed use of algae from the lagoon systems of Lesina (about 2400 t/year) and Orbetello (about 5000 t/year) to produce biodiesel. The research consists of the analysis of the two lagoon systems through the processes analysis and the system analysis with the calculation of systemic indicators of environmental sustainability.

1 – Processes analysis: the production of biodiesel from macroalgae provides a sequence of processes, from lipids extraction (triglycerides, fatty acids), to transformation of lipids in esters (transesterification), during which a reaction takes place between lipids and methanol or ethanol (in the presence of acid or basic catalysts). In this reaction, formation of ethyl-or methyl-ester, and co-production of glycerol are obtained. The research also included sampling phases in the two lagoon systems and specific tests for the estimation of potential yields from chemical processes of matter transformation into biofuel.

2 – Systemic indicators: Based on the identified yields and on the determination of the limits and conditions, the feasibility study involved the hypothetical installation of a plant for the biofuels production from macroalgae, with reference to the entire production chain (LCA and eMergy methodologies), from the raw material collection, to its transformation, to the treatment of the residual matter.

Results showed that macroalgae produced over a threshold of 3000-4000 t/year constitute an important feedstock for the biodiesel production. Concerning the Orbetello Lagoon (5000t/anno), a potential productivity of up to 12 t / year of bioediesel has been estimated.

 

Institution: MIPAAF Ministero per le Politiche Agricole, Alimentari e Forestali.
Project: BALLO (Biofuels from Algae in the Lagoon of Lesina and Orbetello)
Methods: LCA
Period: 2010-2011