Improving energy efficiency in the water business
The water industry is finding innovative ways to secure continuous supply of water on demand in an energy efficient and sustainable manner.
“ . . . Water, water everywhere . . . And not a drop to drink . . .” is a very famous line from The Rime of the Ancient Mariner, published in 1798, which laments the lack of fresh water in a giant sea of saltwater. Yet, still today, the source of this simple H2O molecule, and where it comes from in large quantities to support our everyday life, is often overlooked. We just open the tap and water flows out, right? Well, not exactly.
The Dutch water company Evides Waterbedrijf in the Netherlands is continuously looking for new ways to save energy and reduce CO2 emissions. It recently led the way in pioneering the first use of the low-energy SynRM motor and variable frequency drive (VFD) technology in the water supply business.
Sustainability at its heart
Evides supplies much of the drinking water to the southern half of the Netherlands. It certainly knows a lot about water and the environment, and fosters a progressive sustainability culture. Evides looks for energy savings in innovative ways such as investing in more efficient drives and motor combinations, or solar panels on buildings.
An example at Evides is the new water pumping station it recently built near the small village of Nieuwdorp to increase drinking water supply in the southern Netherlands. This completely new and modern “two-street” pumping station replaced several older stations. Each street has three large 250 kW motors pumping water from three reservoirs with a total capacity of approximately 12,000 m³ of purified water.
Pioneering new ways for efficient water pumping
Evides was the first company in the water-supply business to apply ABB’s energy-saving synchronous reluctance (SynRM) motor technology controlled by ACS880 industrial drives at the Nieuwdorp station. It was also the first in the Netherlands to install the SynRM technology on any application.
The water company wanted to be first to experience the benefits that the SynRM motor gives in combination with the variable frequency drives. It was attracted by the big potential energy savings, as well as cooler and quieter operation due to the fact that the motor has a special rotor design without any losses.
The SynRM rotor geometry means it has no rotor-current energy losses. This contrasts with an induction motor where they can account for 40% total energy loss. There is also lower dissipated heat, with the motor running cooler and quieter and giving longer bearing lifetimes.
Estimated 20% energy savings
Evides estimates that energy savings are around 20% compared to induction motors used in the old stations, and says that the new motors are clearly much cooler, with lower heat loss.
Especially at partial load, the SynRM motor-drive combination is much more energy efficient than a typical IE4 motor. This is an important feature, because most pump and fan applications are normally not run at full load.
The operators of the new pumping station report that the operating system of the drive is very easy to use to control the motors and pumps, and the overall flow of clean fresh water. Quite simply, it has made their job easier. They are so happy with the SynRM motor-drive combination that it has been nicknamed “the Golden Motor”.
Long-term reliability to guarantee water supply
All of these features and benefits – energy savings, cooler and quieter operation, and ease-of-use – mean nothing if the equipment isn’t reliable. Dietrich Houtepen, the Production Engineer at the new Nieuwdorp station, agrees. Ultimately it is his day-to-day responsibility to ensure that the water pumping station runs smoothly without any problems.
Evides is required to deliver water to its customers with absolutely no interruption in supply. In fact, access to fresh water is a civil right in the Netherlands. So uptime and reliability is taken extremely seriously, with downtime when the water flow to consumers is cut off counted in seconds per year.
Dietrich explains that they were confident that the SynRM package would give them long-term reliability, with the life expectancy of 20-30 years. So far, the motors and drives have been running for over two years without a single problem.
The water sector is known to be very careful about taking any risks that might disrupt water supply. Evides instead chooses to be a leader in implementing new technologies to improve energy efficiency. Similar kind of innovative approach is needed around the world to secure complete water flow and to combat challenges such as rising energy costs, scarcity of water and environmental sustainability.
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