Pumping, treating and moving water and wastewater is expensive. Generally, energy consumption by pumps make up about a fifth of a state’s total energy consumption. For municipal utility pump operations, agricultural irrigation and other large pump users, the cost of moving water can be tremendous. Yet intensive water users have had to accept this cost as a necessary evil rather than an expense that can be lowered. Without a clear understanding into the cost of one pump compared to another, there’s been little opportunity to more proactively manage this cost.
New technology stands poised to change this. Through remote pump monitoring, large pump operators can gain valuable insight into their energy usage, and make more informed decisions around pump improvements that can reduce energy demand and costs. Utilities in their energy efficiency programs and pump operators in controlling their water pumping costs can use remote pump monitoring for continuous improvement and for prioritizing improvements.
Unreliable tracking for pump efficiency
Pump system designs normally operate in the range of 65% to 75% efficiency. Researchers with the University of California suggest that a properly designed and adjusted pumping plant will operate at about 70% efficiency. In other words, 70% of the power goes to lifting water, while the rest is used in the mechanics of the pumping plant.
However, real world pump tests indicate this efficiency level to be much lower. Oversizing or, in some cases, under-sizing can cause pump systems to operate well below their best efficiency point. The excess energy usage leads to vibration, heat and noise, all of which can contribute to problems that will increase maintenance and energy costs. In addition, as large pumps reach the end of a 30- to 40-year lifespan, the flow out of the pump can drop significantly. Efficiency levels can drop as low as 40% when pumps are worn or improperly adjusted. These lower levels of efficiency translate to higher operational and maintenance costs.
Of course, even when new, not all pumps necessarily operate at the same energy intensity. An operator using multiple well pumps, all operating at different efficiencies, to fill a common reservoir may be wasting energy by running the most energy intensive equipment just as much as more efficient equipment. Sequencing pump operation, to run the lowest energy intensity pumps first, can tremendously reduce overall energy usage.
The challenges here are that if pumps are not meeting flow or pressure requirements or are operating at a wide range of energy intensities, operators simply do not know. Additionally, Lincus’ research indicates that, on the average, pump efficiency degrades by 1.5% for each year of operation. For poor performing pumps, one solution has been to conduct a pump test. However, these all-too-rare tests typically occur every two to five years, at best. By not proactively maintaining pumps based on real-time information of pump efficiency, utilities, agricultural operations and other pump users may be pouring money down the drain.
Remote pump monitoring technology stands poised to change this. By installing a range of sensors at the pump to collect flow and energy data, operators can gain real-time understanding into their pump’s overall efficiency. This information can then be used to make stronger planning decisions and improve operational costs.
Not convinced that poor pump operation is a problem? Then consider this: every 10% improvement in overall pump efficiency can generate about 17% energy savings. So, if data from a remote pump monitoring system like the one shown in the schematic above tells you that your 75-horsepower well pump is operating at about 50% efficiency, prompting a repair that gets the pump up to 60% operational efficiency, you’ve just decreased your energy bill by 17%.
Gain control of operational costs
Energy management is not necessarily a top priority for all large users of water. If the pump is producing water, then it’s working. Right? While this may be true, this mentality ignores the fact that operating these pumps comes at a steep cost.
It’s a fact that has been easy to overlook, as to date there has been little visibility into the connection between pump operation and rising energy bills.
What’s more, pump tests that might provide this visibility into pump efficiency are performed inconsistently. Over the last 8 years, based on Lincus’ experience with more than 30,000 pumps, we discovered that pumps are typically between 40% to 50% efficiency. In many instances, operators run their pumps until they break, using that as the trigger for replacement. At that time, the pump may be overhauled and tested once again for efficiency. But, as sand creeps into the pump or the water table dips, that efficiency begins to decrease all over again.
On a more regular basis, water users may operate a range of pumps. Consider if three pumps with respective energy intensities of 250 kWh/Acre foot, 400 kWh/Acre foot and 450 kWh/Acre foot are running for the same amount of time to fill the same reservoir. Sequencing these pumps, so that the least energy intensive units run first to serve common water demands, can save energy. Moreover, these pumps see the same amount of wear and tear, ensuring costly maintenance or replacements may happen all at once.
A lack of real-time information on energy usage, intensity or operating efficiency means that water, wastewater and agricultural pump operators have little true control over their operational costs.
Information drives better planning and greater cost savings
Remote pump monitoring technology can provide operators with the operational cost control that’s been missing. The process begins with installation of permanent sensors including flow meters, pressure transducers and/or well-level gauge transmitters, energy monitors, among others. Together, these sensors gather real-time data on overall pump efficiency on a continuous basis, tracking variations based on seasons and weather conditions. That information can be viewed locally and sent through a remote communication unit to a web-based dashboard where the operator can track and analyze this information through user-friendly graphs and display screens.
It’s this last component that may be the most challenging. Customers will only gain value from these sensor-based monitoring tools by learning to work with the data provided and then acting upon this information.
This operational information is powerful. It can be used to diagnose flow problems and rising costs, plan more proactively for pump overhauls and replacements, determine sequencing, develop more accurate forecasting for budgeting, and more. Through appropriate preventative maintenance, operators can save money for potentially costly repairs in the long run.
What’s more, utilities’ energy efficiency programs can use this data to perform more targeted pump testing, rather than simply testing pumps every two to five years without prior knowledge of pump operating characteristics. This can improve the cost effectiveness of pump test programs.
Shifting the focus to total life cycle costs
While there is an upfront cost associated with this technology, the return on investment can be significant—if the information it provides drives action. As indicated on the chart below, on average, the cost of purchasing and installing a pump amounts to about 15% of the life cycle cost of operating the pump. Energy costs account for 60% and maintenance costs make up the remaining 25% of the lifecycle cost pump operation. Investing in a solution that helps to lower those energy costs can drive significant cost savings over time.
Focusing on total life cycle costs, especially on energy cost, may demand a mindset shift for pump systems operators. But this shift comes with tremendous benefits. A new focus on long-term energy costs will better support operators’ bottom lines and their organizational missions.
Ready to make this shift? Talk to our experts to learn more about how to take control of your energy costs.