Meeting escalating water demands is a challenge as old as time. While processes have evolved over the years, so too have the issues. For example, the water industry today faces a rapidly increasing world population, rising energy costs, and an urgent climate crisis.
In this evolving landscape, the industry must constantly look for new ways to create efficiencies, and one critical, long-standing, challenge to address is that of water leakages.
Fortunately, variable speed drives present a promising solution.
Understanding variable speed drives
Variable speed drives (VSDs), sometimes known as variable frequency drives (VFDs) or, simply, drives, control the precise speed and power output of water pumps, reducing energy consumption and preventing potentially damaging pressure surges, thus contributing to efficient, reliable and, critically, leakage-free water distribution systems.
By addressing potential issues, such as abnormal patterns or variations in pressure or water flow within pipes, water companies can address them before they lead to bursts or leaks
Water pumps without drives will run at a fixed speed, often operating at full throttle even when demand is lower. This is an inefficient use of energy and it puts unnecessary strain on the machinery. But drives enable water pumps to adjust their speed according to the real-time demand for water. By modulating the motor speed, drives ensure that pumps run at the most efficient rate to match the required flow rates, resulting in significant energy savings and reduced wear and tear on equipment.
How drives can tackle water leakages
So, how exactly can drives reduce, or even eliminate, water leakages?
Firstly, when measuring water wastage, non-revenue water (NRW) is a critical metric, representing the difference between water flowing into the distribution system and the billed volume. NRW encompasses physical leakage, commercial losses due to data errors or theft, and unbilled authorized consumption. Drives excel in mitigating physical leakage, a substantial component of NRW.
James Chalmers, Vice President of Global Water and Wastewater Sales, ABB Drives
Pressure transients, also known as water hammer or hydraulic shocks, are sudden and temporary spikes or drops in pressure within a water distribution system. Managing these fluctuations in pressure is vital to mitigating leakages.
Water, being incompressible, carries momentum and any sudden alteration in the flow pattern (such as abrupt starts, stops, or redirections) generates pressure waves that travel through the pipes. These waves can cause stress on the system, ultimately leading to cracks, bursts and consequential leaks.
While major bursts are often reported promptly, background leaks can be particularly troublesome since they can persist unnoticed, resulting in prolonged and costly losses. It’s no surprise, then, that pressure transients are a major contributor to NRW.
Implementing District Metered Areas (DMAs) is also essential for leak management in large water networks. By breaking down extensive networks into manageable zones and subzones, leak analysis becomes more effective. Drives complement DMAs by ensuring controlled flow and pressure within these defined areas, aiding in leak detection and management.
What’s more, sensors on the drives allow for remote condition monitoring, which means operators can take a smarter approach to maintenance, often referred to as preventative maintenance.
One water utility company saved over £12,000 annually on one small booster station by installing drives on booster pumps and, in so doing, eliminating burst pipes
By addressing potential issues, such as abnormal patterns or variations in pressure or water flow within pipes, water companies can address them before they lead to bursts or leaks. The ability to remotely access and maintain these assets is especially important in the water industry, where systems are typically located underground or in difficult to reach places. This preventative approach ultimately helps to avoid potential system downtime, which can be very costly for water utilities.
In certain scenarios, multiple drives can be set up in an energy-efficient multiple control system where multiple pumps operate in parallel. This setup allows for even distribution of wear and tear across the entire installation and simultaneously provides system redundancy.
However, preventing leaks is not only about reducing NRW and avoiding downtime. By facilitating precise adjustments in motor speed to match the required flow rates, drives play a key role in both conserving water through leakage prevention and optimizing energy consumption by boosting overall system efficiency. These savings are even more valuable in the context of today’s rising energy costs – and with water becoming an increasingly scarce resource.
Before and after: VSDs in action
One water utility company saved over £12,000 annually on one small booster station by installing drives on booster pumps and, in so doing, eliminating burst pipes. The company previously suffered around nine burst pipes a year, caused by pressure wave fractures and leaks.
Two 5.5 KW ABB drives were fitted, providing a soft ramp up and a controlled slow down to maintain supply pressure. Before the drives were installed, pressures were peaking at 140 meters head. Following the installation, maximum pressures were almost halved, at 83 meters head. Before, each burst had cost the company an estimated £1,400 to resolve.
Since the installation, in 2016, the utility has had zero burst pipes. The drives have also reduced the energy consumption of the pumps. Return on the initial £5,500 investment was achieved in under six months.
A greener, more sustainable water supply
Drives not only enhance energy efficiency, but also serve as a powerful tool in conserving valuable water resources. By addressing pressure transients and leakages, they contribute to a sustainable water supply system that meets the growing demands of a rapidly increasing population.
The potential for drive uptake in the water industry is huge. In fact, between 90 to 99 percent of new projects will have drives fitted. This is promising when embracing this technology represents a giant leap towards a greener, more sustainable water supply.
Discover more about VSDs as a solution to water leakages: https://new.abb.com/drives/segments/water-and-wastewater