Farmers stand to make big savings on both electricity and water if they introduce energy-efficient measures to their irrigation systems.
Twelve farmers who took part in a recent pilot project could save an average of $7444 a year on electricity. On average, they would have to spend $25,888 on upgrading their systems, but the payback period would be just 3.5 years.
The farmers found they could significantly cut the amount of water they used, between 10 and 15 days over a six-month season, providing further energy savings because irrigators were not needed.
Nationwide, irrigation uses about 2.5 per cent of New Zealand's electricity for pressurised spray systems covering 625,151 hectares.
Energy demand is expected to grow as irrigation increases, with some forecasts of a further 350,000ha coverage over the next 20 years. Among the projects being considered are the Ruataniwha dam in Hawke's Bay, and five water storage proposals in the Wairarapa.
Irrigation New Zealand conservatively estimates irrigation energy savings across the industry could see a 10 to 20 per cent improvement in performance. This would create significant energy savings for New Zealand of between 110,000 megawatt and 220,000MW a year.
The pilot project was run jointly by the Energy Efficiency and Conservation Authority (EECA) and Irrigation New Zealand.
Paul Reese of Irrigation NZ said the organisation was keen to drive the project because it wanted to portray irrigation in a good light.
"We are looking at the big picture, and we see excellence in irrigation and energy efficiency as part of that.
"We recognise that water is a public resource, and it's important to point out to farmers that they have a social responsibility to use water as best they can," Reese said.
Farmers needed to constantly monitor how much water their farms needed.
"You can have a system that we can improve hydraulically or mechanically by 10 to 15 per cent, but we can also improve the use of that system by turning a tap on or off for a few days.
"If we can save you 10 to 15 days watering over a six-month season - and typically a system might operate for $400 to $500 a day - that's $4000 to $5000 saving over so many days you're not irrigating," Reese said.
There was a further benefit to irrigators who might be allocated a finite amount of water, because they could make optimum use of the water they had.
HUGE INVESTMENT WORTH IT
South Canterbury dairy farmer Kelvin Weir says he is now going ahead with a $180,000 upgrade of his irrigation system.
The amount is "huge" he concedes, but the payoff will be worth it to the 900-cow, 452 hectare farm in the Lower Waitaki.
"The annual cash savings should be about $21,000 a year, so it will pay itself off in around seven years. But there's more payback in the fact we can irrigate the farmer better - we'll probably grow more grass," Weir said.
At the heart of the new system are three energy efficient pumps, replacing one large pump. The new pumps operate at lower pressures and they "talk" to each other.
"You can have one running but if there's more water needed then another starts up, and so on. But if you need only one running, then that's all that's required.
"Before I was operating with just one big pump and was irrigating paddocks that didn't need it," Weir said.
He was unsure whether he would have gone ahead with the upgrade without the EECA audit.
"I would have been very nervous about going ahead with it because I wouldn't have had the information. It made a big difference as soon as I got the report," he said.