How to Lower Your Facility’s Electric Bill: Tweaking Your Energy Efficiency and Power Usage
Your home electric bill is usually based on a simple calculation: How many kilowatt hours (kWh) did you use? Your energy consumption can be seen by watching how fast the little disk spins inside your electric meter.
Seldom are industrial and commercial electric bills that easy to calculate. But you can save money by paying attention to how the electric utility calculates your charges—and make appropriate upgrades to power-consuming equipment.
For larger customers, electric utilities charge for several metrics, including:
- Total energy usage in kilowatt hours, which is usually the primary charge. For example, if you burn a 100-watt bulb for 10 hours, you will use 1/10 of a kilowatt for 10 hours—or 1 kWh. An electric heater with a rating of 1000 watts will use a kilowatt hour of energy in just one hour.
- Peak power demand, which is the maximum amount of energy used during a short period time during the billing period. Enough electric power must be available to meet the peak demand by customers like you. The unit kW does not sound like a rate of energy per unit time until you consider it as kilowatt-hours per hour (kWh/h) or kW demand.
- Power factor penalty, where current shifting due to inductance or capacitance can cause higher losses and harmonic distortions from non-linear loads can cost you even more energy. For more details, see How to Handle Harmonics in Electrical Power Systems.
- Miscellaneous charges, such as generation charges and fuel cost adjustments.
- Possible other riders and adjustments for economic development and the like.
You can gain insight into each charge by wading into the rate documents your utility files with your state’s public utility commission. And your utility account representative should be available to help explain the details related to your specific account. Or you can start saving money and electricity by implementing these tips.
Energy Savings with Newer Lighting Systems
Lighting systems more than four years old could benefit from an upgrade to LED lighting, which has the best light per watt-hour consumed. If there is a possibility of improving energy efficiency by reducing area lighting and providing more task lighting, energy consumption could be reduced even more.
The integration of lighting controls can reduce lighting levels and easily reduce the number of hours that lights are on, which further reduces consumption. Daylight and occupancy sensors add some cost but can generate quick paybacks for areas that are either near outside windows or only occasionally occupied, or both.
Even if employees turn the lights off at the end of the day, the cleaning crew might turn on all the lights rather than turn on only those they need. So occupancy sensors can significantly reduce the number of hours that lights are on. This is especially important if lights are left on that create heat in an area being air conditioned.
Using VFDs to Reduce Energy Consumption
Using variable speed drives (VFDs) on pumps and motors that do not have to operate at 100% capacity are a great way to reduce kilowatt hours of energy consumption. For example, if equipment must only run at full output for short periods of time, a VFD could be used to ramp up and ramp down the motor.
Shifting Loads During Peak Demand Time
If you are billed for peak energy demand, then trim that peak demand! It’s important to understand when your peak demand occurs, and which energy gobblers are running at that time. Timers and schedule changes that delay the start of large motors, pumps, heaters, and air conditioners can reduce demand—with instant cost savings. This is especially important if the rate structure includes a ratchet clause that an established monthly demand is billed for six or eleven months even if the monthly billing demand is lower during the ratchet period.
Replacing Motors with Premium Efficiency Models
National energy conservation laws and standards have encouraged motor manufacturers to produce highly efficient electric motors called premium efficiency motors. Since motors can easily have an energy cost that is 10 times the cost of the motor itself, consider replacing older motors, even if they are the high efficiency versions available at the time. The payback may surprise you due to the reduced electrical losses in modern motors.
Transformers Are Usually Efficient
Transformers are fairly efficient, but the cost of no load and load losses should be considered in transformer selection. Rather than reusing existing older units, considering a new one that complies with the latest energy efficiency standards may be a better value.
Other Energy Losses to Eliminate
Feeders and branch circuits could have their losses reduced by either installing a larger feeder conductor or replacing equipment with a higher utilization voltage that reduces system losses by reducing the current needed to perform the same task. Correcting the power factor for standard motor loads will reduce the load current flowing through the distribution system and should have an impact on the electrical power costs either directly through lowering the power factor penalty or reducing demand billing costs or indirectly as lower losses on the corrected branch circuit. Adding capacitors to improve the power factor will reduce electrical system losses in the distribution system and improve efficiency—and reduce electric costs.
Using Other Energy Sources
There are other choices of energy, such as natural gas, fuel oils, solar cells, and wind turbines. If you are lucky enough to have a source of water year around, you may be able to use water turbines.
Whatever the power source, reduce your energy use. The right mix of improvements to maximize your savings requires a study of your energy bill and your facility’s electric usage. Let Matrix Technologies examine or audit your power usage and demand to see if there are significant savings to be achieved.
Matrix Technologies is one of the largest independent process design, power systems engineering, industrial automation engineering, and manufacturing operations management companies in North America. To learn more about our energy and power capabilities and manufacturing process control solutions, contact Vince Trejchel, PE.
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Multidiscipline Engineering – Electrical and Instrumentation