As a facilities manager, you may have heard about smart electricity meters but be unfamiliar with exactly what they do and how they can be helpful. Smart meters are an underutilized tool that can actually help you save money—up to as much as 10% of your utility bills. They can also help ensure the longevity of your capital equipment, which saves you even more in the long run.
This article explains what a smart meter is, and why its measurements are key to efficiently operating your facility.
What is a smart meter?
A smart meter is a mechanical device that measures the electricity consumption of a building. Before they became “smart,” electricity meters first had to be read manually; eventually, automated meter reading devices became available which made physical visits to the meters unnecessary. These automated meter reading devices sent meter readings to the energy supplier only (you as the customer did not have access to the data), and primarily measured kWh.
Today’s electric meters are smart. How do smart electric meters work? They use different technologies than automated meter reading devices, delivering information wirelessly via low-energy radio frequency waves. Your energy usage data is sent to your supplier at frequent intervals, with some models delivering information as frequently as every 15 minutes. The same information is also made available to you.
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The technology used by smart meters differs from automated meter reading devices. But there are also other important differences, including the kind of information they measure. Smart meters offer more detailed data than the old devices; they also give customers like you access to the meter’s power usage data. As a result, you have the ability to gain more control over your energy usage, either by altering your usage habits or pinpointing issues related to your power quality.
Power quality relates to how efficiently your systems are consuming the power that is being supplied to them. In the next section, we’ll take a closer look at power quality and how digital smart electric meters can be used to ferret out power quality issues at your facility.
Smart Electricity Meters & Power Quality
Smart electricity meters provide you with more information about your power, which you can use to your advantage. To understand how you can do that, you need a bit of background on electric power and “power factor.”
Utility-supplied electric power entering your facility is comprised of power measured in amps and voltage. Alternating current (AC) travels in waves; when the voltage and current waves are out of sync, power distortion takes place. The displacement between current and amps gives rise to inefficiencies, which separates power into real and reactive power.
- Real power is the power that is consumed to run equipment and lighting, and is measured in kilowatts (kW).
- Reactive power is the byproduct of the phase displacement between current and amp, and is measured as kilovolt-amperes reactive (kVAR).
- Total or apparent power is the sum of both real and reactive power, and is measured as kilovolt-amperes (kVA).
Power factor is the ratio of real power to apparent power; it’s what measures the efficiency of a building’s electric system.
To determine how effectively your building is using electricity, you divide the kilowatts used (real power) by the kilovolt-amperes (apparent power) used. If, for example, your building runs at 90 kW (useful, working power) and the total, apparent power is 115 kVA, you get .78, or 78%—meaning only 78% of incoming power does useful work.
The mathematical equation to determine power factor is:
The most efficient systems are those whose power factors are closest to 1.0, so the higher the power factor, the more efficiently your system is operating. Power factor is one important element contributing to power quality, an overarching term that refers to the characteristics of power supply that enable electrical equipment to work properly. Improving the power factor will have a positive impact on power quality overall.
So what’s the relationship of power quality to the cost of electricity?
Utility companies base their charges on the infrastructure needed to have apparent power readily available. If your building is not using electricity optimally (meaning you have a low power factor), you may be paying a power factor “penalty” (usually if it falls below .85). Why? Because large power loads with a poor power factor draw a larger current and place a heavier drain on the power source, requiring the utility to increase its generation and transmission capacity to handle the load. If you can improve that to .9 or .95, you’re being much more efficient in your energy usage. (The utility is also benefiting because power is not going to waste.)
Smart electricity meters give you visibility into the quality of the power coming into your building. The relevant measurements they provide are:
- Real power
- Apparent power
- Reactive power
If the math indicates your power factor is deficient, it means you’re likely paying a penalty and you need to take corrective action. Possible solutions might be adding an array of capacitor banks to supply reactive power, so you don’t have to pull that in from the utility. (Though you’ll still need some of that reactive power for your electric motors.) You could also set up variable frequency drives, which are much more efficient in supplying power to electric motors.
After measuring, what’s the next step?
Before implementing any solutions for a power factor deficiency, it’s important to determine why your facility has a poor power factor to begin with.
There are two possibilities:
- You could be causing it internally by the way you’re running your motors.
- The utility company could be lacking in the quality of power it is providing.
The final determination may require some investigation on your part. Look at the load profile within your facility and try to isolate it by putting current transducers (CTs) on your largest motors. If you’re not seeing any abnormalities there, then talk with your utility provider to dig deeper.
Protecting Your Capital Equipment
Large fluctuations in voltage and frequency could be detrimental to your most expensive equipment. Poor power quality could make a machine that would normally last 10 years only last four years. So if you need to probe more deeply into the issue, you may require a more sophisticated meter.
Standard smart electricity meters measure a basic set of parameters regarding electrical waveforms; industrial-grade meters measure many more. If you have costly equipment to protect, you’ll want a meter that can measure waveforms down to the millisecond, providing information about:
- Sags in voltage
- Swings in frequency
- Harmonic distortion
- Out-of-the-ordinary oscillations or impulses
Sophisticated smart meters or probes are costly, but protecting your essential equipment is usually worth the cost.
Use Your Smart Electricity Meter To The Fullest
Smart electricity meters can only do so much without the help of a smart metering service to go along with them.
Iota not only provides smart electricity meters, but also offers power quality monitoring as a service. We can monitor and measure your real, apparent, and reactive power remotely, and provide analytics around the data so you can interpret what you’re seeing. We can also assist with corrective actions, and make recommendations about how to mitigate power quality problems in accordance with your building environment. If you’d like to learn more about how we can help you improve your facility’s energy efficiency with our power quality monitoring service, get in touch today.