Significant energy savings can be achieved by improving the energy efficiency of dairy buildings and associated equipment. Priority areas may include lighting, insulation, motors and refrigeration systems. Renewable energy sources should also be considered as part of an integrated solution.
Energy audit the first step
While energy savings may be achievable in every dairy, these savings may not compensate for the effort and/or cost involved.
As a first step, we recommend that all farmers conduct at least a ‘level one’ energy audit for their properties.
A level one audit will identify major energy savings opportunities and provide the basic numbers necessary to estimate payback periods for specific solutions.
Dairy farmers may benefit from a level two audit, which provides the detail required to solve relatively complex energy-efficiency problems and is advisable before making any significant energy related investment.
Facility climate control
Intensive production facilities, such as cold storages, require consistent and precise temperature control. The building shell, passive ventilation, lighting, heaters, and the motors driving HVAC and refrigeration systems all contribute to the total energy efficiency of the system.
Often, older dairies were built with little thought of energy use and efficiency. Retrofitting insulation can provide quick wins, however. It is advisable to obtain and compare quotes and ideally, to seek independent advice.
Roofs typically absorb UV radiation from the sun, heating up the contents of the building. Covering an existing dark-coloured roof or installing a new light-coloured, reflective roof can significantly reduce the amount of solar radiation absorbed and lower surface temperatures on the roof as well as temperatures inside the building it covers.
Air leakage and building tightness
Controlling air exchange and preventing leakage of conditioned air is essential. Sealing a leaky building can be a simple matter of applying foam sealants to gaps and cracks, weather-stripping and/or adding plastic air barriers. Reviewing your buildings for obvious gaps can reveal some easy savings. Controlling air exchange also involves ensuring that staff implement correct procedures around the opening and closing of doors and windows.
Ensuring that equipment is maintained properly is vital to getting the most out of your assets. Motors, fans, compressed-air hoses and pumps all have to be serviced regularly to ensure they are operating within expected guidelines.
Equipment replacement and upgrades
Full or partial early retirement of existing equipment provides you with opportunities to incorporate new technologies such as variable speed drives or condensing equipment that runs far more efficiently. Day-to-day efficiency gains may provide enough savings to make these types of upgrades and replacements cost-effective within a short period of time.
Assessing the light fixtures in farm buildings and upgrading those that are old and outdated can lead to major savings. New developments in lighting technology can reduce energy usage by more than 90 percent. Much like early retirement of other types of equipment, replacing outdated lighting technology can provide significant savings from day one.
Simple bulb switching may not always be applicable, due to the differential voltage requirements in existing lighting fixtures. Farmers can take advantage of the NSW Energy Savings Scheme by selecting an accredited certificate provider from the NSW ESS website (NSW Government Energy Savings Scheme, 2014). These providers can offer expertise and lower prices while helping you switch to high-efficiency equipment.
Smart sensors and automation
There is wide range of smart technology available to automate the operation of lighting and HVAC systems so as to optimise energy use.
Lighting sensors are a common solution for reducing electricity demand from lighting. Lighting motion sensors ensure that areas receive adequate lighting when necessary, without wasting energy lighting unoccupied areas.
Air quality and temperature sensors can be used to continuously optimise the operation of fans and HVAC systems. While automation can be expensive, benefits may include energy savings, improved growing conditions (by removing operator error) and a reduction in labour costs.
Power quality problems can be a significant hidden cost for farmers. Installing line conditioners and voltage optimisation devices can reduce electricity costs and extend the life of expensive electrical and electronic equipment.
Renewable energy generation on farm should be considered as part of a total energy solution, helping to reduce your operation’s reliance on external energy sources.
Solar photovoltaic systems are a proven technology and can be cost-effective when combined with battery storage so the energy can used outside daylight hours. Check our solar battery financial calculator to see if the numbers might stack up.
Likewise, solar hot water is a robust and effective technology.
The conversion of waste to energy is an area with great potential for some production systems. For example, capturing methane from animal manure to drive electricity generators can be cost-effective for large piggeries and dairies.
Those running dairies in windy locations may want to consider the viability of installing farm-scale wind turbines.
If you are constructing a new facility there are many opportunities to incorporate energy efficiency into its orientation, structure and materials. Each intensive sector has specific requirements for shed functionality. Established, conventional designs are not necessarily ideal, however, and there is significant scope to improve the energy efficiency of most dairy buildings.
Checklist for new facilities
- Building orientation. Is there scope to locate and orient the building so as to optimise passive heating and cooling (solar orientation, breezes, shading)? Does Council provide incentives in this regard as part of the Development Approval process?
- Structural materials. Have you compared the costs and benefits of alternative materials for roofing, walls, floors and structural elements? Some structural materials have better thermal properties than others.
- Insulation and sealing. Have you optimised investment in quality insulation and sealing? A higher upfront cost may be justified by energy savings in longer term.
- Renewables. Have you considered options for meeting some of your energy demand from renewable sources?
- Can improving your energy efficiency benefit production efficiency? For example, a concrete floor could help stabilise temperatures as well as assisting with cleaning and/or biosecurity.
Obtain independent advice
Before committing to changes and investing capital it is essential that you obtain expert and independent technical advice on the solutions you are considering. In this regard, it is preferable to hire a consultant who is not a vendor of specific equipment and whose focus is on identifying the best suite of technologies for your particular business.
- Refrigeration summary - A summary outlining energy-saving opportunities related to refrigeration, including insulation, variable temperatures and head pressure, and factors to consider when upgrading or replacing equipment.
- Energy-efficient farm lighting - There are a variety of lighting technologies available. This information sheet explores agricultural applications and efficiencies available in lighting in the current marketplace.
- Insulating farm buildings - Reduce heating and cooling loads in buildings by adding insulation and increasing existing R-values, making roofs and ceilings top priorities.
- Compressed air systems: air-leak reduction - Leakage accounts for nearly one third of compressed air energy consumption. Institute a proactive leak repair and maintenance program to reduce energy loss through leakage.
- Compressed air: minimise pressure drop - Minimise pressure drop in compressed air systems to meet end-use demands and overcome friction and gravitational flow losses (pressure drop) in the pipe/hose network.
- Solar hot water - Understand how solar hot water works and where this technology can be useful in agriculture.
- High-efficiency motors - Consider the savings you could make through implementing high-efficiency motors
- Power factor correction - Power factor can directly influence electricity charges. Correcting this can reduce your energy bills.
- Voltage optimisation - Remote farming operations are subject to voltage variance, which can negatively affect mechanical equipment. Voltage optimisation is also a potential energy-saving measure