Energy and economic sustainability of woodchip production by black locust (Robinia pseudoacacia L.) plantations in Italy

Growing demand for energy has led to a rise in the price of fossil oil and an increased rate of depletion of fossil resources. This situation has generated a strong interest in the use of biofuel, and many studies have been undertaken on the worldwide potential for biofuel. Among all renewable energy sources, biomass could contribute to meeting the EU's renewable energy targets in 2020, especially short rotation coppice (SRC). In order to evaluate the energy and economic sustainability of woodchip production by black locust SRC, an ad hoc study was undertaken and a specific calculation model was developed. Data were collected in a black locust SRC plantation site in North West Italy during the period 2006-2012. This involved an SRC duration of six years and a biomass (10 Mg ha−1 DM per year) harvest at the end of a cycle (six years). The results indicated that black locust plantations are very desirable from an energy point of view since the output/input ratio results are higher than 20. Unfortunately, the results are not so positive from an economic point of view. In fact, in order to obtain economic sustainability for woodchip production, the biomass price should be at least €103 Mg−1 DM. Consequently, woodchip production by black locust SRC is only possible with economic support for production and with optimisation of agricultural labour and biomass production.