A 128ha cane farm producing on average 130tc/ha located in Home Hill could reduce energy consumption and costs while improving production by implementing recommendations in a recent Energy Savers Audit.

Cane production typically relies on energy for pumping and irrigation which is linked to the soil type, rainfall distribution, and severity of dry periods. As a result, there can be variability in Tonnes of cane harvested per hectare. A recent energy savers audit looked at ways to reduce energy consumption and costs as well as improve productivity by increasing water delivery with assistance from automation. The use of a new efficient bore will relieve a secondary pump and allow more water to be applied over the current cropping area.

The farm currently operates using obsolete Tariff 66, with three pumps that consume 61,324kWh per annum at a cost of $20,696. From the data, the farm produced 16,640 tonnes of cane using 3.68kWh per tonne at the recent harvest. A quick win found in the tariff review showed that the site could save $6,186 per annum immediately by moving to Tariff 33 (Load Control) in combination with Tariff 20A (Time of Use).

Table 1. Current pumping system and costs savings by changing tariffs.

With tariff savings in mind, the farm focus is increasing the efficiency of the pumping system. The audit showed pumps 1 & 2 to be efficient, though recommended to replace the existing well with a high yielding bore. The new bore will also improve the system capacity to deliver more water resulting in the potential to increase yield over the 51.65ha while providing relief to the other two pumps. It was also recommended to install a variable frequency drive (VFD) on the new pump to maximise the benefits of the solution.

The audit also identified that automation would be relatively simple, as much of the infrastructure is in place, and only three pumps to operate. A reduction of 10-20% in water use has been estimated if automation using smart sensors were to be introduced as less energy is required for pumping with the device operating according to soil moisture measurements. This also has the potential to increase crop yields using a choice of irrigation scheduling tools. Additional benefits of automation include reductions in labour, fuel, vehicle repairs, and maintenance (estimated at around $4,900). Automation will provide the benefits above plus enable easier management of peak/off-peak tariff changes under Tariff 22A, 24, or inconsistent supply, which can be experienced using Tariff 33.

Table 2. Energy savings from audit recommendations

–

By replacing the well with a high yielding bore and increasing the amount pumped by 200 ML per annum the savings increase substantially due to an increase in profit from higher yields as a result of an increase in tonnes of cane produced. The payback period would be reduced from 13.5 years to just 3.7 years from an increase in water delivery. Using these recommendations, the farm would reduce its kWh per tonne of cane by 56% to 1.61kWh/tc.

The farmer proceeded with the installation of the new bore pump, with potential energy consumption savings of 13%, costs savings of 12%, and carbon emission savings of 6.4 tCO_2-e per year. Actual savings will be updated once the measurement and verification process is complete.

Table 3. Pre and post audit energy consumption, costs, and energy productivity savings

An energy audit is a good investment

An energy audit is a great way for a business to cut costs resource use and boost productivity.

The Energy Savers Plus Extension Program was delivered by the Queensland Farmers' Federation with support and funding from the Queensland Department of Energy and Public Works.