The Energy Efficiency in Dairy Sheds project has provided farmers with a robust and objective view on ways, with good practice, that farmers can achieve significantly improve energy efficiency and operating costs for all types of dairy sheds.

Equipment trials were carried out on five Southland dairy farms during the 2006/07 dairy season. The trials examined the performance and effects of various pieces of equipment including a heat pump, heat recovery units, a solar water heater, vacuum pump variable speed drives, milk pump variable speed drives, a milk vat insulating wrap and a chilled water milk cooler. Based on real time energy monitoring and independent assessment, the project has provided a much-needed information source for farmers who have been wary of making energy management decisions based on incomplete information and claims made within sales literature. In addition, this study has highlighted a number of critical points for the dairy sector to consider.

First, there are gains to be made from better matching diary shed practice with available electricity tariff options – specifically the use of a night rate. However, a night rate is only a price signal that reflects a constraint on the electricity network. It should be noted at the outset that farmers who take advantage of a night rate will then have little price incentive to make real efficiencies in energy use. Savings are achieved in terms of cost, but not in energy efficiency.

Second, it is possible for existing dairy sheds to make some immediate efficiency gains in the area of water heating. As in any industrial situation, drips, leaks and uninsulated pipes can waste significant amounts of hot water. In a dairy shed this type of inefficiency can amount to several hundred dollars per year.

Third, the study highlighted the overall importance of gaining efficiencies in water heating. It has been shown that there are many options available and the performance of these systems and devices is in most cases very close to the claims made by the manufacturers and suppliers.

Finally, the study has demonstrated that any farm seeking a best practice approach to energy efficiency will need to focus on approaches to designing the dairy shed and the specification of best-in-class equipment.

The study has demonstrated thatany farm seeking a best practice approach to energy efficiency will need to focus on approaches to designing the dairy shed and the specification of best-in-class equipment. Additionalelectricity meters are needed as part of an energy management programme that provides for checking temperatures, flow rates and pressures, and recording electricity use.

This collaborative study has also identified a number of related issues which merit further investigation. There is an obvious need to work with equipment suppliers to ensure that farmers can measure their energy consumption easily and accurately. Further investigation is needed into opportunities to use improved thermostats and temperature control systems, and there is potential to develop ice slurry cooling systems which utilise night rate. In the long term, a clear set of standards is required for the performance of dairy sheds and their design.

The findings from this study suggest that without the adoption of national design standards or best practice guidelines it is unlikely that significant gains will be made in energy efficiency across the industry.Reference to the Energy Efficiency in Dairy Sheds – Technical Report is recommended for detailed technical information on which this report is based, along with other reports written during the project, and the cost calculator decision tool, a major output of this study.These files can be downloaded from the links on this page (all files are in pdf format, except the Calculator, which is an Excel file).

You may download these files for your own use; they can be freely distributed, provided they are not amended or otherwise changed, and provided Venture Southland/ CAENZ is cited as the source.