Life-cycle environmental and economic impacts of energy-crop fuel-chains: an integrated assessment of potential GHG avoidance in Ireland David Styles a,b, *, Michael B. Jones a a School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland b Environmental Protection Agency, Richview Business Park, Clonskeagh, Dublin 14, Ireland 1. Introduction Renewable energy and reducing greenhouse gas (GHG) emissions are now established priorities within EU policy. Through the EU, Ireland is committed to achieving renewable penetration of at least 15% final consumption in the electricity market by 2010 (RES-E Directive 2001/77/EC; DCMNR, 2007), and GHG emissions not more than 13% above 1990 levels over the 2008–2012 commitment period (country-specific target set by EU under Kyoto-Agreement). Strong economic growth (GDP more than trebled between 1990 and 2005: CSO, 2007), and rapidly increasing transport emissions, contributed to total 2005 GHG emissions of 69.9 Mt CO 2 eq. (McGettigan et al., 2007)—26% above 1990 levels. In 2005, the major sources of these emissions were agriculture (27%) and energy generation (66%)—the latter approximately equally divided among transport, electricity generation, and heat generation. According to statistics from Sustainable Energy Ireland (Howley et al., 2006b), the 2005 electricity fuel-mix, totalling 58 TWh, was dominated by gas (45%), coal (28%), oil (16%) and peat (10%), resulting in an average GHG-intensity of 0.632 kg CO 2 eq. kWh 1 for delivered electricity. Meanwhile, electricity, oil and gas accounted for 23, 40, and 18%, respectively, of the 33 TWh domestic fuel-energy demand in environmental science & policy 11 (2008) 294–306 article info Published on line 4 March 2008 Keywords: Miscanthus Willow GHG Cost–benefit Integrated assessment abstract 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 conven- tional fuels were considered in fuel-chain permutations. Avoided greenhouse gas (GHG) emissions ranged from 7.7 to 35.2 t CO 2 eq. ha 1 a 1 . Most fuel-chain permutations exhib- ited positive discounted financial returns, despite losses for particular entities at a farm-gate processed-biomass price of s100 t 1 dry-matter. Attributing a value of s10 t 1 CO 2 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 1887s 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 CO 2 eq. a 1 (5.2% of national emissions), a DANEB of 167 Ms, 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 CO 2 price, and appear to represent an efficient land-use option (e.g. compared with liquid biofuel production). Policies promoting utilisa- tion of these energy-crops could avoid unnecessary, and environmentally questionable, future purchase of carbon credits, as currently required for national Kyoto compliance. # 2008 Elsevier Ltd. All rights reserved. * Corresponding author at: School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland. Tel.: +353 1 268 0100; fax: +353 1 268 0199. E-mail address: dstyles@tcd.ie (D. Styles). available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/envsci 1462-9011/$ – see front matter # 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.envsci.2008.01.004