Spatial and life cycle assessment of bioenergy-driven land-use changes in Ireland

Bioenergy crops are forecast to play a significant role if Ireland is to reach the 2020 and beyond targets set by the European Union's Renewable Energy Directive (RED). The aim of this study is to evaluate the environmental impacts associated with the cultivation of bioenergy crops in Ireland including land-use change (LUC) emissions by using geographical information systems (GIS) and Life Cycle Assessment (LCA). In this study, GIS is used to identify, and measure LUC changes associated with cultivation of Miscanthus and Short Rotation Coppice (SRC) willow. An LCA study was carried out to estimate the greenhouse gas (GHG) emissions from the LUC caused by the cultivation of bioenergy crops. The results find that miscanthus caused 86% of all LUC with SRC Willow accounting for 14%. The LCA results identify two major processes that contribute to total GHG emissions; field operations and loss of soil organic carbon (SOC) stocks. Land preparation, harvesting and the production of synthetic fertiliser are found to be the most significant contributors to field emissions. SOC emission for the conversion of pasture to SRC willow accounts for a large proportion of the overall GHG emissions. Conversion of arable land to miscanthus and SRC willow both cause a net reduction of GHG emissions. Sensitivity analysis on the type of fertilisers used and the inclusion of indirect land-use changes (iLUC), highlight the impacts that these have on the overall system performance. The replacement of synthetic fertiliser with biogenic fertiliser reduced overall GHG emissions. The inclusion of general iLUC data results in a large increase in total GHG emissions because of displaced food crops that must be grown elsewhere. The study shows that conversion of arable to miscanthus and SRC willow is preferable when cultivating bioenergy crops while conversion of pasture to SRC willow should be avoided.