Date of Award


Document Type

Doctoral Thesis

Degree Name

Doctor of Philosophy


Process, Energy & Transport Engineering

First Advisor

Dr Michael D Murphy

Second Advisor

Dr John Upton


The aim of this thesis was to develop a dairy optimisation platform to optimise investments in dairy farm technology and changes to on-farm management practices and electricity tariffs, in order to maximise profitability and minimise environmental impacts. Increased dairy herd sizes and milk production levels in Ireland as well as changing regulations concerning emissions, renewable penetration and energy efficiency have necessitated a means of financial decision support for farmers. Therefore this body of work focused on the creation of a comprehensive method for optimising dairy farm technology selection, management practices and electricity tariffs. The measures which could be implemented on dairy farms to improve economic performance and reduce environmental impacts were categorised in this study under the headings of efficiency through technology adoption, efficiency through management practices, and reduction in primary energy through renewable generation. To improve efficiency through technology adoption, technologies including plate heat exchangers, variable speed drives, solar thermal water heating and heat recovery systems were considered. To improve efficiency through management practices, load shifting measures were considered. To reduce primary energy through renewable generation, photovoltaic systems and wind turbines were considered. A comprehensive optimisation method was required which took into account all measures and the relationships between them, while the conflicting goals of improving profitability and environmental performance necessitated the use of multi-objective optimisation to assess trade-offs between these goals. Moreover, to facilitate the analysis of efficiency through technology adoption, efficiency through management practices, and reduction in primary energy through Abstract xxi renewable generation, validated scalable models of energy efficient and renewable technologies were created which enabled their effect on dairy farm profitability and environmental performance to be quantified. These models were employed when carrying out multi-objective optimisation to optimise dairy farm technology, management practices and electricity tariffs for maximisation of dairy farm net profit, minimisation of farm electricity related CO2 emissions, maximisation of farm renewable contribution and optimisation of milking start times for farmers. Trade-offs between these objectives were also assessed. A test case of a 195 cow farm was employed to demonstrate the applicability and usefulness of the optimisation platform, with results indicating that farm electricity related CO2 emissions could be reduced by 40%, 3% and 31% through technology adoption, management practices and renewable generation respectively. Furthermore, the use of a plate heat exchanger was the most economically feasible technology of the technologies examined. It is anticipated that the methods presented in this thesis will be used as a comprehensive means of decision support for farm advisors, policymakers and farmers. The outputs of the thesis will enable these key stakeholders to make prudent decisions pertaining to investments in technology and farm management changes, in order to increase farm profitability and contribute to national greenhouse gas mitigation.

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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