One of the largest expenses for South African firm Riecor Farming is the energy used to operate its irrigation system. The country’s electricity prices have grown at more than 20 percent per year in recent years and the method for controlling the flow of water was not energy efficient as it called for farm workers to manually tighten valves to limit flow rates.
Pump start-up operations were also time consuming as they required manual opening and closing of valves. Each of the six pumping stations required an hour of an operator’s time for start-up and with up to three power outages per day meant that start-ups became almost a full-time job.
Farm owner Tiaan Riekert decided to test ABB VSDs on one pumping station, with dramatic results. ABB worked with a local systems integrator to supply six VSDs for pumps with motors sized 45 to 75 kW. The new VSDs led to a 40 percent reduction in consumption for just one pumping station, equivalent to $19,700 per year, or a payback period of only seven months. His experience led Riekert to place a repeat order for a second pumping station.
Evides Waterbedrijf provides reliable and pleasant tasting drinking water to 2.5 million clients in the Netherlands. It has a progressive philosophy to lower its carbon footprint and look for energy savings in innovative ways. That is why Evides is the first drinking water company to apply ABB’s energy-saving synchronous reluctance (SynRM) motor technology, controlled by ABB ACS880 industrial drives.
To increase redundancy in the drinking water supply in the province of Zeeland, Evides has built a new ‘two-street’ pumping station that has replaced several older stations. Each street has three large 250 kW motors that pump purified water from three buffer-water storage reservoirs with a total capacity of approximately 12,000 m³. The efficient KSB pumps are equipped with ABB’s motors and drives that ensure energy efficient operation.
The water sector is known to be very careful about taking any risks that might disrupt water supply. “We wanted to be the first in the Netherlands to experience the benefits that the SynRM motor offers in combination with variable frequency drives,” says Toine Rijsdijk, an Evides Process Automation Engineer who worked on the project. “We saw that the potential benefits included significant energy savings, as well as cooler and quieter operation. And after two years of running we have not had any problems.”
Energy savings achieved with the motor-drive solution are estimated to be around 20 percent compared to induction motors used in the old stations.