What is power factor and how does it affect me?

In this article we will take a short look at power factor, how it is calculated and the effects thereof on your bill and physical infrastructure. Power factor can be a complex thing but it is not needed to understand the underlying principles to understand the effect of it and the remedial actions.

What is power factor?

Power factor refers to the ratio of power supplied to the measurement points (measured in kilowatts or kW) to the demand pulled from the supply (measured in kilovolt-amperes or kVA). Ideal systems have a power factor of 1 (or unity) which means that the demand exactly equals the power, but in the real world you can see power factors running from as low as 0.6 to 0.999.

When does power factor affect me?

There are only very specific times where a power factor is relevant:

  1. It increases the maximum demand portion of your bill – if there is no maximum or peak demand line item that is measured in kVA this is not relevant. In most medium and upwards commercial scale buildings this will be present.
  2. It increases reactive energy supplied – this is a very specific line item that is only present in a small portion of bills we see
  3. It increases availability based charges such as Network Access Fees – this is a fee based on the maximum contracted demand you expect to use
  4. If you want to increase the load on site without increasing your breaker size – if you want to go this route ensure you have detailed measurement data to work with

A key thing to remember is that low power factor does not increase your energy use (or kWh). This means that if the only thing you are billed for is energy that improving the power factor will not have any benefit to your billing.

How do I improve my power factor?

Power factor correction is a simple system that ties into your electricity distribution system and regulates the power factor by bringing suitably sized capacitors in and out of the system depending on load. The system is designed specifically for your site’s operating profile and installation is quick and easy.

How do I determine if my power factor is bad?

The best way is with metering data over a significant period of time (i.e. you should measure during peak operating times). Our energy intelligence platform has comprehensive reporting built in that simplifies your power factor to an “opportunity cost”.

If existing power factor correction equipment is installed you should see a controller installed in the main DB with a display showing the power factor to two significant digits. Keep in mind that you may have a low power factor during off=peak times but that this is not as important as the power factor during high load conditions.

If you had to estimate, most modern office buildings run at about 0.85 to 0.95 before correction depending on HVAC, and most production facilities run from 0.8-0.9 mostly depending on the amount and size of motors on site.


About Power-Star

Power-Star offers solutions that effectively measure and manage energy efficiency, improves operations and increases profitability. We offer expertise in energy management, power factor correction, solar, water management and billing disputes.

Power-Star has been in business since 2008, delivering measurement and efficiency solutions throughout Africa and the Middle East.  We service leading global brands and local businesses across all sectors.


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