North Range Farm in Northern Southland engaged WaterForce to install a solar powered pumping system in early December 2009. North Range Farm had grazing restrictions on parts of their farm due to inadequate water supply for stock during dry periods. Power and diesel had been priced as options but both of these came with obstacles, including difficult access for refuelling services and capital cost. A solar pumping system seemed the obvious solution.
Installing a solar pumping system on farm requires a specific type of site, WaterForce worked with North Range manager Ian Grant to find a suitable site that provided both adequate water and sunlight for solar energy. The actual site was near the Mossburn White Hill Wind Farm, this had a reliable spring fed creek for water and a clear sunlight path for the solar panel. However, it was exposed to the prevailing wind.
The creek was channelled into a trough collection that gravity fed some 200 metres into a 25,000 litre plastic tank, the solar panel driving the pump was situated about 400 metres away in a sunny area. The panel was installed facing North and automatically rotates to follow the sun. Wooden strainers have been driven into the ground around the panel to protect against the prevailing wind.
From the plastic collection tank a progressive cavity Mono submersible pump was installed. The pump was protected against frost as it was submerged in the tank and this also ensured there were no priming issues. The system was set up to fault on low level if the creek stopped running or the intake to the tank blocked. The final outcome has been a simple and effective solution with sustainable running costs.
FarmInitially Mr Grant checked the system weekly to ensure all was well, now some 18 months later he just checks the tank indicator from a distance.
Another advantage with this system is that it delivers more water when there is more sunlight to help balance the additional water stock consume on hot days.