The CFO sent your plant manager an e-mail stating that the electric bill has been running about 15% higher each month when compared to the same month of the previous year. He strongly suggested that the manager should “replace all incandescent lamps with CFLs to bring these costs down.”
Your plant manager does not believe that CFLs will reduce the energy costs. In fact, he has told you not to install them. But he does want you to investigate exactly why the electric bill has increased and figure out what corrective steps to take.
What should you do?
Your plant manager is correct about the CFLs. This type of lamp is a compromise solution that puts an electronic ballast into a too-small package. The results include low power factor (PF) and high harmonics. Instead of CFLs, upgrade lighting with a properly designed, energy-efficient system.
On the electric bills, look for additional charges for peak loading or power factor. If you have power factor charges, evaluate PF on your largest loads (e.g., motors for plant air). If you correct PF at the load, you reduce total energy draw (perhaps solving the peak loading problem) and help eliminate the electric utility’s PF penalty.
Examine your largest inductive loads for power quality issues. You can install PF correction capacitors on across the line motors to correct for PF. But installing power-factor/harmonics-corrected electronic drives gives you additional benefits such as eliminating system-wide incidences of low voltage due to across the line starting; that also saves energy.
