7 Energy Indicators
7.1 ISSUES
Energy is one of the major input costs for pumped irrigation systems, particularly sprinkler systems. Indirect energy consumption such as the energy required to construct or manufacture irrigation systems, or to provide transport around the farm is also a factor.
A study currently being undertaken for MAF Policy by Agriculture New Zealand will identify indicators that result in the breakdown of on-farm energy use. One of the areas being considered is irrigation. The resultant output in terms of irrigation will be energy use per unit of production. It is envisaged that energy usage can be expressed as net CO2 production per unit of farm production. (Colin Wells, Agriculture New Zealand, pers. comm.)
In a wider context, the energy source is an important sustainability consideration. The options (electricity, diesel or gas) will depend on the location of the farm. For example, farmers in the South Island mostly rely on energy from hydro-electricity, whereas a substantial proportion of North Island electricity supply is generated from non-renewable resources such as natural gas and fossil fuels.
Efficient use of energy has several advantages. Farmers are advantaged financially, through lower electricity and fuel costs. New Zealand overall has to supply less energy, reducing the country’s overall consumption. Fossil fuel usage is slowed, fewer hydro-electric dams have to be built, environmental impacts are reduced, and non-renewable resources last longer.
7.2 POTENTIAL INDICATORS
Potential indicators of energy consumption include:
- total energy used (direct and indirect);
- direct energy use;
- energy used for irrigation pumping and moving per unit of production;
- energy used per m3 of water pumped;
- peak energy usage.
7.3 RATIONALE FOR SELECTING INDICATORS
For this irrigation-orientated project, it is impractical to measure indirect energy use. Therefore, to satisfy the selection criteria, the recommended indicators concentrate on measuring the direct and on-farm energy use associated with irrigation. The annual energy needed (electricity, diesel, etc.) to operate an irrigation system is usually easy to record. Most irrigation pumps have separate electricity meters. If the energy use is compared to the amount of water pumped, farmers can track whether efficiency of the pump is changing over time.
7.4 RECOMMENDED INDICATORS
| Annual energy used to operate irrigation system (kWh) Energy used per volume of water pumped (kWh/m3) |
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