Life-cycle environmental and economic impacts of energy-crop fuel-chains: an integrated assessment of potential GHG avoidance in Ireland

This paper combines life-cycle analyses and economic analyses for Miscanthus and willow heat and electricity fuel-chains in Ireland. Displaced agricultural land-uses and conventional fuels were considered in fuel-chain permutations. Avoided greenhouse gas (GHG) emissions ranged from 7.7 to 35.2 t CO2 eq. ha-1 a-1. Most fuel-chain permutations exhibited positive discounted financial returns, despite losses for particular entities at a farm-gate processed-biomass price of Euro 100 t-1 dry-matter. Attributing a value of Euro 10 t-1 CO2 eq. to avoided GHG emissions, but subtracting financial returns associated with displaced fuel supplies, resulted in discounted annual national economic benefits (DANEBs) ranging from -457 to 1887 Euro ha-1 a-1. Extrapolating a plausible combination of fuel-chains up to a national indicative scenario resulted in GHG emission avoidance of 3.56 Mt CO2 eq. a-1 (5.2% of national emissions), a DANEB of 167 M Euro , and required 4.6% of national agricultural land area. As cost-effective national GHG avoidance options, Miscanthus and willow fuel-chains are robust to variation in yields and CO2 price, and appear to represent an efficient land-use option (e.g. compared with liquid biofuel production). Policies promoting utilisation of these energy-crops could avoid unnecessary, and environmentally questionable, future purchase of carbon credits, as currently required for national Kyoto compliance