A biofuel strategy for Ireland with an emphasis on production of biomethane and minimization of land-take Anoop Singh a,b , Beatrice M. Smyth a,b , Jerry D. Murphy a,b, * a Department of Civil and Environmental Engineering, University College Cork, Cork, Ireland b Biofuels Research Group, Environmental Research Institute, University College Cork, Cork, Ireland Contents 1. Introduction ..................................................................................................... 278 1.1. Greenhouse gas targets....................................................................................... 278 1.2. Sustainability of biofuels ..................................................................................... 278 1.3. Biofuels from waste ......................................................................................... 278 1.4. Anaerobic digestion (AD) ..................................................................................... 278 1.5. Aims of the paper ........................................................................................... 279 1.6. Objectives of the paper ....................................................................................... 279 2. Energy use in Ireland .............................................................................................. 279 2.1. Growth in energy consumption in transport ...................................................................... 279 2.2. Energy forecasts ............................................................................................ 279 2.3. Energy in transport and biofuels ............................................................................... 279 2.4. Biofuels and land-take ....................................................................................... 280 3. Greenhouse gas emissions from different sectors ....................................................................... 280 3.1. Sectors which produce the largest quantity of greenhouse gases ..................................................... 280 Renewable and Sustainable Energy Reviews 14 (2010) 277–288 ARTICLE INFO Article history: Received 11 June 2009 Accepted 6 July 2009 Keywords: Biomethane Wastes Grass Slurry Slaughter waste OFMSW ABSTRACT Increasing energy consumption has exerted great pressure on natural resources; this has led to a move towards sustainable energy resources to improve security of supply and to reduce greenhouse gas emissions. However, the rush to the cure may have been made in haste. Biofuels in particular, have a bad press both in terms of competition with good agricultural land for food, and also in terms of the associated energy balance with the whole life cycle analysis of the biofuel system. The emphasis is now very much on sustainable biofuel production; biofuels from wastes and lignocellulosic material are now seen as good sustainable biofuels that affect significantly better greenhouse gas balances as compared with first generation biofuels. Ireland has a significant resource of organic waste that could be a potential source of energy through anaerobic digestion. Ireland has 8% of the cattle population of the EU with less than 1% of the human population; as a result 91% of agricultural land in Ireland is under grass. Residues such as slurries and slaughter waste together with energy crops such as grass have an excellent potential to produce biogas that may be upgraded to biomethane. This biomethane may be used as a natural gas substitute; bio-compressed natural gas may then be an avenue for a biofuel strategy. It is estimated that a maximum potential of 33% of natural gas may be substituted by 2020 with a practical obtainable level of 7.5% estimated. Together with biodiesel from residues the practical obtainable level of this strategy may effect greater than a 5% substitution by energy of transport. The residues considered in this strategy to produce biofuel (excluding grass) have the potential to save 93,000 ha of agricultural land (23% of Irish arable land) when compared to a rapeseed biodiesel strategy. ß 2009 Elsevier Ltd. All rights reserved. Abbreviations: AD, anaerobic digestion; CAD, centralised anaerobic digestion; CH 4 , methane; CO 2 e, carbon dioxide equivalent; DS, dry solids; GDP, gross domestic product; GHG, greenhouse gas; NCCS, National Climate Change Strategy; OFMSW, organic fraction of municipal solid waste; UCO, used cooking oil; VDS, volatile dry solids. * Corresponding author at: Department of Civil and Environmental Engineering, University College Cork, Cork, Ireland. Tel.: +353 21 4902286; fax: +353 21 4276648. E-mail address: jerry.murphy@ucc.ie (J.D. Murphy). Contents lists available at ScienceDirect Renewable and Sustainable Energy Reviews journal homepage: www.elsevier.com/locate/rser 1364-0321/$ – see front matter ß 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.rser.2009.07.004