By their very nature, mining operations are high-volume electricity users. Energy costs have a significant impact on the mining industry’s bottom line. The good news is that there is something you can do to improve your energy efficiency without sacrificing your operating efficiency. It’s all about power factor and power factor correction.
What is a power factor?
Without diving too deep into the mathematical calculations involved, power factor (PF) is the measure of how efficiently you use electrical energy. PF=0 is the worst case (completely inefficient), and PF=1 is the ideal (completely efficient in that all AC current is transferred into working power). Real-world systems always operate somewhere between 0 and 1. In the mining industry, any power factor of 0.95 or higher is considered to reflect effective use of energy. Electric utilities typically charge industrial customers a penalty for having a poor PF or bill for demand, which includes a penalty for poor PF built in.
If your PF isn’t hitting the 0.95 or above range, consider the following methods to improve it:
1. Replace Outdated, Inefficient Equipment
Just as modern household appliances such as washers, dryers, and refrigerators offer far greater energy efficiency than models from decades past, modern industrial equipment is increasingly energy efficient. Replacing older equipment that is dragging down your power factor may offer a quick return on investment to justify the expense.
2. Add Components That Improve PF
Variable frequency drives (VFDs) and soft starters prevent an enormous surge of power from being drawn during the start-up of equipment such as pumps and motors. This can improve your PF and extend the life of your equipment.
3. Change Behaviors
By studying detailed power usage patterns and anomalies, you can identify potential operational changes that could improve PF without sacrificing production efficiency. For instance, are there ways to make use of equipment that consumes the most energy during off-peak rather than peak hours? Are machines that can be turned off when not in use, such as during employee breaks, actually being turned off?
4. Install Capacitors
Capacitors are one of the most practical and economical PF correction devices available. Even energy-efficient equipment can drag down your PF when it’s underloaded or unloaded. Installing capacitors can improve your PF. The capacitors correct PF by supplying capacitive reactive power to the equipment to counter the inductive reactance of your equipment. This method can lower both your electric bill and losses in transformers and wiring. If you have high inductive reactance loads, your utility supplier may even subsidize the cost of capacitors.
Benefits of Improving Your PF
In addition to the obvious benefit of reducing your electric bill, power factor correction offers other advantages to mining operations. For example, poor PF causes higher current flow and voltage drops, which can result in overheating and damage to electric motors and transformers. Improving your PF can extend the life of your equipment. In addition, power factor correction lowers your carbon footprint and may help you meet regulatory requirements. All in all, improving power factor is a winning proposition for mining operations from any angle.