Mark Ngatai had been looking into renewable energy for the Tirohanga Farms on Matakana Island for the past four years and he was recently convinced a 40kW solar power system would be the best solution.
Mark wanted to generate 60,000kWhrs to significantly reduce the cost of powering refrigeration for chilling milk, heating water and operating pumps on the farm.
The Auckland based company What Power Crisis was approached for the project and proposed a grid connected solar photovoltaic solution that would meet Marks target. The solution consisted of 160 x 250W solar panels and 4 x 10kW three phase inverters. The system is set to reduce $18K worth of power each year, working out to reduce the monthly power cost to $3 per cow.
Because the large solar power system size was too big to fit on any of the roofs on the farm, they opted for a ground mount solar array. This type of set up has its advantages of being perfectly north facing and is tilted to the optimal angle for the farms latitude, which allows for the maximum amount of power to be drawn from the solar panels. To deliver the power from the ground mount array to the farm's dairy shed, a 200m trench was dug to lay out a 90mm2 cable, which was sized to keep any power losses to a minimum.
It makes a lot of sense for Farms to install solar power as it significantly lowers their costs and reduces their carbon footprint. This is just one of the many solar powered farms to be installed in New Zealand.