Editing Power factor (section)

== Importance in distribution systems ==
[[File:Condensor bank 150kV - 75MVAR.jpg|thumb|upright|75 MVAr capacitor bank in a 150 kV substation]]
[[File:Condenser bank on utility pole with fuses disconnected.jpg|thumb|Capacitor bank on a utility pole in San Jose, CA, USA]]
Power factors below 1.0 require a utility to generate more than the minimum volt-amperes necessary to supply the real power (watts). This increases generation and transmission costs. For example, if the load power factor were as low as 0.7, the apparent power would be 1.4 times the real power used by the load. Line current in the circuit would also be 1.4 times the current required at 1.0 power factor, so the losses in the circuit would be doubled (since they are proportional to the square of the current). Alternatively, all components of the system such as generators, conductors, transformers, and switchgear would be increased in size (and cost) to carry the extra current. When the power factor is close to unity, for the same kVA rating of the transformer more load current can be supplied.<ref>{{cite web|url=https://www.electricalclassroom.com/power-factor/|title=Power Factor – Importance, Calculation and Correction techniques|date=23 November 2018}}</ref>

Utilities typically charge additional costs to commercial customers who have a power factor below some limit, which is typically 0.9 to 0.95.  Engineers are often interested in the power factor of a load as one of the factors that affect the efficiency of power transmission.

With the rising cost of energy and concerns over the efficient delivery of power, active PFC has become more common in consumer electronics.<ref>{{Citation | publisher = ON Semiconductor | year = 2007 | title = Power Factor Correction Handbook | url = http://www.onsemi.com/pub_link/Collateral/HBD853-D.PDF }}</ref> Current [[Energy Star]] guidelines for computers<ref>{{Citation | place = US | url = http://www.energystar.gov/ia/partners/prod_development/revisions/downloads/computer/Version5.0_Computer_Spec.pdf | publisher = Energy Star | title = Program Requirements for Computers | edition = Version 5.0}}</ref> call for a power factor of ≥ 0.9 at 100% of rated output in the [[Power supply unit (computer)|PC's power supply]]. According to a white paper authored by Intel and the [[United States Environmental Protection Agency|U.S. Environmental Protection Agency]], PCs with internal power supplies will require the use of active power factor correction to meet the ENERGY STAR 5.0 Program Requirements for Computers.<ref>{{Citation |last1=Bolioli |first1=T. |last2=Duggirala |first2=M. |last3=Haines |first3=E. |last4=Kolappan |first4=R. |last5=Wong |first5=H. |year=2009 |publisher=Energy Star |title=Version 5.0 System Implementation |type=white paper |url=http://www.energystar.gov/ia/partners/product_specs/program_reqs/Computers_Intel_Whitepaper_Spec5.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.energystar.gov/ia/partners/product_specs/program_reqs/Computers_Intel_Whitepaper_Spec5.pdf |archive-date=2022-10-09 |url-status=live}}</ref>

In Europe, [[IEC EN 61000-3-2|EN 61000-3-2]] requires power factor correction be incorporated into consumer products.

Small customers, such as households, are not usually charged for reactive power and so power factor metering equipment for such customers will not be installed.