An Emerald irrigated cotton farm could benefit from a recent Energy Savers Audit. This case study details the need to inspect, maintain and repair pumps before potential replacement in order to achieve lower payback periods.
A 220ha irrigated cotton farm could save money and time by implementing recommendations from their Energy Savers Audit. The site produces some Corn, Barley, Wheat and Chickpeas. Three pumps lift water from the creek to three separate centre pivots consuming nearly 110,000 kWh at a cost of $23000. Four potential solar systems were compared with the best payback chosen to offset and reduce consumption below 100,000kWh. As consumption is just over 100MW p.a. both SAC small and large customer tariffs were considered, and a comprehensive analysis shown to minimise operating costs.
Two stages were removed from a seven-stage pump which reduced the flow rate but improved the combined efficiency by 25%. The pump demand has been reduced by 12kW and even with increased running time, running costs have reduced by $1,200 per year with a payback period under two years.
The Audit recommended a new, smaller pump which increased water flow by 1.1ML/day and improved combined efficiency by nearly 30%. The pump upgrade has been completed by the farmer even though the payback period on energy cost savings alone was estimated at over 9 years.
The irrigation audit identified energy savings of 29% and a payback period of 1.3 years with a change to pump operations, installation of a variable speed drive to a 75kW pump and replacing the pump impellor with a full-size version. The audit also found up to $3,500 in savings available with a change in tariff. Emission savings have been estimated to be 37.9 t CO2-e.
The irrigation energy audit recommended replacing a 45kW line-shaft pump with a 37kW submersible pump to achieve an 8% energy savings and carbon emission reductions of 5.6 t CO2-e per annum.
An energy audit of the pumping systems recommended replacement with more energy-efficient drive units, upgrading the distribution pipework and replacing pumps. Emission savings have been estimated to be 73 t CO2-e per year.