Environmental Protection Agency

Environmental Protection Agency
Climate Change Research Program


Compressed biomethane generated from grass utilised as a transport fuel

Lead PI: Dr Jerry D Murphy

Senior Post Doctorate (Agronomy): Dr. Nicholas Korres

Senior Post Doctorate (process): Dr. Anoop Singh

Duration of research: 2008-2010

Project description:

Forage grass is a hardy perennial crop which does not require rotation, is well known to farmers, and if used as an energy crop, does not impede on arable land or require new agricultural practices. Existing yields of grass per hectare are high (12-15 tds/ha/a). Marginal lands may be utilised; grass cuttings from city parklands provide free energy crops. Biogas, when generated from grass and ensiled grass (silage) and upgraded to compressed biomethane has the potential to reduce the land requirement to meet the Biofuels Directive by a factor of four, when compared to biodiesel from rape seed. It is postulated that compressed biomethane from grass is the optimal transport biofuel in Northern Temperate Europe.

In terms of environmental impact and diversity this grass system does not require conversion of grassland into arable land; this is in line with the objectives agreed in the last reform of the Common Agricultural Policy. This avoids a release of CO 2 from grassland soils that would occur when such land is ploughed.

A full life cycle analysis will be utilised to compare this system with other transport biofuel systems (biodiesel from rape seed and ethanol from sugars and starches).

Peer review journal publications  

  1. Nicholas E. Korres, Anoop Singh, Abdul-Sattar Nizamia, Jerry D. Murphy. “Is grass biomethane a sustainable transport biofuel? Biofuels, Bioproducts, Biorefinery, (In Press)


  2. AS Nizami, N E Korres, JD Murphy; “A review of the integrated process for the production of grass biomethane,” Environmental Science and Technology, 2009 , 43(22), pp 8496–8508


  3. AS Nizami, JD Murphy; “What type of digester configurations should be employed to produce biomethane from grass silage?” Renewable and Sustainable Energy Reviews, (In Press).
  4. Singh A, Smyth BM, Murphy JD 2009. “A biofuel strategy for Ireland with an emphasis on production of biomethane and minimization of land take,” Renewable and Sustainable Energy Reviews , (2009), doi:10.1016/j.rser.2009.07.004


  5. Smyth BM, Murphy JD, O'Brien C. 2009. What is the energy balance of grass biomethane in Ireland and other temperate northern European climates? Renewable and Sustainable Energy Reviews doi:10.1016/j.rser.2009.04.03


  6. JD Murphy, N Power; "An argument for using biomethane generated from grass as a biofuel in Ireland," Biomass and Bioenergy33, pp. 504-512, 2009.




Peer review conference papers:


  1. A Singh, JD Murphy; “Biomethane from animal waste and grass for clean vehicular biofuel in Ireland,” In: Twelfth International Waste Management and Landfill Symposium, Santa Margherita di Pula, Sardinia, Italy Sardinia 2009: 5-9 October 2009

  2. JD Murphy, B Smyth, AS Nizami , T Thamsiriroj, A Singh, N Korres; “The potential for biomethane as a transport fuel in Ireland,” In: Biofuels Directive to bio based Transport Systems in 2020, IEA Bioenergy Task 39 Subtask Policy and Implementation Workshop, Dresden, Germany,June 2-5, 2009.

  3. N E. Korres, C O’Brien, B Smyth, AS Nizami, T Thamisirioj, R Schulte, JD Murphy; “A preliminary analysis of energy balance and greenhouse gas (GHG) emissions of biomethane production as a transport fuel from grass/silage. A case study for Ireland,” Society of Environmental Toxicology and Chemistry (SETAC) Conference, Goteborg, Sweden, 31 May – 4 June 2009.

  4. JD Murphy; “Using Grass to reduce emissions in the agriculture and transport sectors,” In: The Greening of Irish Agriculture, Responding to the Challenge of Climate Change, Institute of International and European Affairs (IIEA), Dublin Castle, Jan 9, 2009.

  5. JD Murphy; “Biomethane: A method of generating biofuel from first generation biofuel residues, from stillage and from grass,” Keynote Lecture, First International Symposium for Young Scientist and Technologists in Malting, Brewing and Distilling, University College Cork, 7 November 2008

  6. JD Murphy; “Biomethane: an optimal transport fuel and a method of improving first generation biofuel systems,” International Energy Agency Biofuels Symposium, University College Cork, September 14 th , 2008.

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