A energy-savings evaluation method to justify automatic power factor compensators on marine vessels

Many induction motors are installed in ship electric power systems, where a poor power factor is often overlooked. Power factor compensation that is usually achieved by adding capacitive load to offset the inductive load present in the system can have many benefits. As a ship power system, fuel oil costs and air pollution emissions for power generation remain low. This paper aims to establish a set of energy-savings evaluation model for benefit-cost analysis for automatic power factor compensators (APFCs) applied in marine vessels. The active power, reactive power, power factor, and diesel electric engine´s oil consumption for a practical commercial vessel power system during different operating conditions were measured and analyzed. Base on the actual measurements, an APFC for marine use is designed and the possible benefits after installing the APFC are quantified to justify the investment by using two standard cost-benefit analysis methods. Sensitivity analysis is also performed to reduce effects of input parameters on the analysis results and determine the critical parameters. Analysis results can assist shipbuilding corporations and ship owners in managing energy efficiency of similar systems and building business cases for determining return on investment (ROI).