Date of Award


Document Type

Master Thesis

Degree Name

Master of Engineering (Research)


Civil, Structural, & Environmental Engineering

First Advisor

Dr Niamh Power


The motivation for this research stems from the potential of biofuels to assist Ireland in meeting obligations outlined in the 'Renewable Energy Source Directive' (2009/28/EC) and to reduce dependency on fossil fuels. The purpose of this work is to establish the merits of biofuel production Ireland ,with a keen focus on the technical, economic and environmental aspects of each. The three biofuel options investigated are biodiesel, bioethanol and biomethane. Eight crop varieties were investigated, these include; wheat, oats, barley, OSR, maize silage, sugar beet, grass silage and potatoes. The approach taken within this thesis was to perform a life cycle analysis of the technical, economic and environmental aspects of crop production (part A), followed by biofuel processing (part B). Present tillage practices (part A) were inspected to give an indication of requirements/demands of each energy crop. Similarly, (in part B) the biofuel processing demands for biomethane, biodiesel and bioethanol, were explored; with a focus on determining both the economic processing requirements (capital costs and operational costs) and the practical requirements (diesel, electricity, LPG and steam/thermal energy). It was established that on a life cycle basis, biomethane from grass silage is the optimum energy crop in Ireland for biofuel production with a net energy value of 201.6GJ/ha and associated CO2 emissions of only 17.96kgC02/GJ. Grass biomethane can be produced for under €25.00/GJ once capacity exceeds 100,000tpa; the economics of grass silage biomethane is highly dependent on maximising plant capacity (economies of scale). Biodiesel from OSR can economically outperform grass silage biomethane at low capacity plants but net-energy values are only 29.J 2GJ/ha with associated CO2 emissions of 24.59kgC02/GJ Although many of the findings within this thesis are very promising for grass silage biomethane, it must be realised that in order to encourage and stimulate grass silage biomethane in Ireland -and ensure that Ireland reaps the benefits of an abundant and valuable biofuel resource -financial incentives need to be devised, ideally in the form of excise relief.

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