When it comes to electricity, you’ve got to spend money to save money – that’s the message from a project that looked at ways to reduce electricity costs for Australian producers. Watts in Your Business - helping fruit businesses cut energy use and costs monitored and reviewed the energy efficiency of 30 pack houses and orchards Australia-wide, advising them on ways to save money on their bills.
The project was undertaken by Apple and Pear Australia Ltd (APAL) with assistance from a Federal Government grant. The information is relevant to mango growers who face many of the same costs, especially for their pack houses. The project looked at five aspects of energy use:
Electricity tariffs
Despite what the electricity retailers say, tariffs are always negotiable. Electricity retailers calculate electricity billing in a number of ways and build set charges into the tariffs. Knowing what you have and making sure it is the best solution to your needs is a great way to reduce energy costs.
Refrigeration in packing sheds
Refrigeration is the biggest energy cost for fruit production, storage and packing businesses. The project shows that refrigeration consumes on average 64% of electricity, costing $85,000 a year. There is however potential for savings.
Lighting in packing sheds
On average, lighting uses 3% of total electricity - just over $4,000 per year per facility. Despite small savings, improving lighting can be done easily at a low cost.
Irrigation
Irrigation is a primary user of electricity on an orchard. Upgrading irrigation systems to newer technologies can save energy and money.
Packing sheds
Packing lines take up a large amount of space but only consume around 8% of total business electricity usage. Nevertheless there are some areas where the energy efficiency of packing lines can be easily improved with a small upfront investment.
Shift electricity use to a time period when tariffs are lower
Inappropriate tariff regimes may result in spending more on electricity consumption than necessary. Running irrigation pumps or refrigeration compressors during the period of the lower off-peak tariff will save costs on electricity.
Research the most suitable electricity retailer and contract for your business
Have a good understanding of your electrical requirements and usage, compare the rates and charges of energy retailers and select the one that would be most appropriate for you. You can also use an energy consultant/broker to do this for you. An energy consultant will also provide account management throughout the lifetime of your energy contract.
Install power factor correction
Power factor is the ratio of real power measured in kilowatts (kW), to the apparent power measured in kilovolt amperes (kVA). A Power Factor Correction (PFC) can reduce the demand charge by acting as a reactive power generator, reducing power loss.
Install a solar panel system
Solar systems generate electricity to off-set the purchase of electricity from the network.
Use energy efficient equipment
Newer equipment is, in general, more energy efficient. Upgrading equipment can reduce energy consumption and associated costs. Common ways to reduce equipment’s energy usage include insulate hot and cool pipework and install voltage power optimisations (generally only viable for a site that uses 500,000kWh or more a year).
Optimise head pressure on refrigeration systems
Most refrigeration systems operate with condenser fans cycled to maintain a set-point. Minimising or varying head pressure can reduce the temperature and increase the efficiency of the refrigeration system.
Optimising head pressure reduces power consumption by 3-12%.
Install variable speed drives on evaporative fan motors
Variable Speed Drives (VSDs) allow the power used by a motor to match the demand. A good example is evaporative fans in cool rooms. Logically, these are designed for the period of maximum demand. During periods of lower demand the fans can be larger than are required. Variable speed drives allow them to run at lower cost in low demand periods.
Retrofitting variable speed drives to evaporative fan motors can save an average of $6,000 per year.
VSDs apply equally to other electric motors such as the ones used on refrigeration compressors and irrigation pumps (see below).
Automate cold storage doors
Poor door seals and leaving doors open allows unwanted heat to enter cold storage rooms. To remove this heat again requires energy. Automated doors on cold stores minimises warm air entering.
Replace inefficient compressor motors with high efficiency ones
High Efficiency Motors are built from materials that allow greater operational efficiency compared to older units. Standard electric motors generally operate at an 88% efficiency whereas High Efficiency Motors generally operate at a much higher efficiency of 93%.
Replace HCFC with ammonia refrigeration systems
Most Hydrogen-chloro-fluorocarbons (HCFC) are due for phase-down in 2016, so systems relying on them should be replaced. Converting to an ammonia system will not only achieve efficiencies in energy use, but will also future-proof the availability of the refrigerant.
An upgrade to ammonia in a large apple and pear coolstore resulted in a 25% energy saving while peak demand was cut by 60%. Peak demand can be a significant factor in negotiation of tariff rates.
Use T5 fluorescent tubes
Most older-style fluorescent tube lights use significantly more energy for the same level of light compared to newer types. T5 tubes consume around 28W and are the most energy efficient fluorescent type tubes on the market.
Use LED tubes
LED tubes have reduced maintenance and associated energy costs, an increased lifespan and easier disposal of perished tubes as they do not contain mercury, compared to florescent tubes.
Use LED highbay bulbs
LED highbay bulbs are an alternative for some High Intensity Discharge (HID) bulbs. They may require a significant capital investment but they have an extended lifespan, reduced maintenance costs, instantaneous strike and lower wattages.
Replace halogen bulbs with LED bulbs
Halogens and incandescent bulbs are frequently found in cold storage rooms and small storage areas.
Install lighting controls
Daylight sensors can reduce power consumption as they only enable lights to be activated when low light levels are detected. Lighting controls can be fitted to all existing and new lighting types.
Install variable speed drives on irrigation motors
A variable speed drive regulates the frequency of electrical power to match the volume or pressure needs of an irrigation system. An irrigation motor with a variable speed drive can use up to 27% less energy.
Use high efficiency motors
For efficient irrigation, selecting appropriate pumps, motors and impellers to match your orchard’s varying irrigation needs is important. Ideally motors should have variable speed controllers. High efficiency motors have improved service life and energy efficiency and should be considered as an alternative to standard motors when purchasing new motors.
Automate irrigation control
Irrigation automation control can remotely set the area, frequency, duration, start time and end time of irrigation. It can limit the use of power to off-peak to take advantage of cheaper pricing. This can also be done using basic timers for pumps or manually turning irrigation on during off-peak times. Automated systems can increase the availability of staff and the reliability of scheduling irrigation events.
Design irrigation efficiently
A detailed irrigation design is essential to analyse and audit the performance of an irrigation system. Design tools such as IrriCAD Pro and HydroCalc can be used to build an irrigation design. As new blocks are established, this opportunity should be considered.
Reduce air compressor leaks
To reduce air compressor leaks, inform staff how to identify them and develop a log or register to have any leaks quickly repaired. Central shut-off valves can also be installed on equipment to ensure leaks are minimised when not operating.
Solar hot water heaters
A solar water heater system is a solar collector that is coated with a dark coloured surface that absorbs the sun’s radiant heat (energy) and uses it to heat water. In most pack houses, hot water for the washer is generated through a water heater using LPG or electricity as the energy source.
To view the full fact sheets or for more information visit the APAL website at http://apal.org.au/watts-in-your-business/
‘Watts in Your Business’ was funded by the Department of Industry as part of the Energy Efficiency Information Grants program and managed by Apple and Pear Australia Ltd (APAL). The project was completed with assistance from KMH Environmantal.