20 September 2019

How can you reduce the energy consumption of motor-driven pumps? – Part 2

In my previous blog, I focused on how economy pumping can be a part of any endeavor to reduce energy consumption and save on electricity costs. The implementation of energy-saving pumping routines can be carried out by utilizing existing instrumentation that supports energy saving algorithms or by upgrading to ultrasonic level controllers that support such functions. Rest assure. If this concept is new to you, ultrasonic level controllers with this endowed capability are simple to set-up and with a little time and investment, you will quickly see real benefits.

So, how straight-forward are these controllers to set-up when implementing economy pumping schedules?

For a well utilizing a couple of pumps, the idea is to configure the controller to automatically lower the level of wet wells just prior to the peak electricity rates and temporarily modify the low and high set points by changing just a couple of parameters in the controller for each pump. The controller essentially prepares the well to take the most volume wastewater by pumping the wells down in anticipation of high demand. For example, when most people get ready to go to work and take showers, or when they return home and start cooking dinner and doing laundry.

Utilizing this pumping strategy greatly reduces the energy demand when electricity is premium; therefore, improving the bottom line. The set-up only takes a few minutes. If the temporary high set point is not reached than no energy is used during the high-cost period. Your pumping strategy is never sacrificed for the sake of savings. If for some reason the temporary programmed elevated set points do not keep up with the influx, the controller resumes the normal operating set points and the pumps run until the safe condition is reached. I think you can probably agree that instruments capable of energy saving are a sound investment.

Is the cost of ultrasonic level controllers justifiable to take advantage of the off-peak electricity costs?

This is not a “too good be true” scenario. Do you have time to read a real-life situation where pumps were rescheduled to save money? Click here.

For example: If you have a pump driven by a 50-horsepower motor and if the off-peak kilo-watt hour is $.065, running the pump for five hours will cost you about $12/day or about $4,400/year. If the kilo-watt hour goes up about $.04 during peak hours, that’s an additional $3,500. Ten pumps would mean $35K/year.

Remember: if you double the motor horsepower, the operating cost doubles as well. So, running pumps during off-peak hours means big savings. The return on investment can be realized in a matter of months for most utilities.

Is there an easy and practical way to estimate the electricity costs due motor driven pumps?

To assist with the calculations, we have developed a couple of cost of water calculators that can help you estimate costs associated with water losses and potential savings using economy pumping routines. The calculator can be found here: http://www.usa.siemens.com/cost-of-water-calculator. All that is needed from you is your regional electricity rates and a couple of specifications associated with the motor driving your pumps. This is a good place to start to get an idea on how much can be saved when using economy pumping routines.

Are there incentives to implement energy cost reduction measures due pumping systems?

Besides the opportunity to save thousands of dollars year-after-year by implementing economy pumping routines, the Department of Energy (DOE) offers incentives to some regions that are worth looking into it. Participating facilities agree to integrate energy management into their business operations and culture through a systematic approach to managing energy. Even if your area is not incentivized by the DOE, you can help your facility by driving down operational costs.

Do you know how much your electricity peak and off-peak rate cost?

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