Power Factor Improvement

Power factor (pf) is defined as the ratio of real power to apparent power. Ideally, you want a pf of 1 because this means that the apparent power is equal to the real power. More often than not however, we don’t find a pf of 1 and this can have significant effects on your business in terms of creating electromechanical problems and adding to your power bill.

Most loads are inductive in nature, meaning the pf will typically be less than unity. The further the pf is from unity, the greater the power drain on the local system and then come the problems.

The primary reason for the problems is that the reactive power (the power you need commensurate to the requirements of your working equipment and plant) is being drawn from the power network through the installation’s main switch board. Power factor correction reduces the amount of reactive power sourced from the electricity supplier by introducing an array of power capacitors to the network that in turn, by continuously monitoring the supply network, allows you to choose where your reactive power is sourced from.

Ok, that helps explain what it is and why it’s important, but what are the potential cost-savings to a business?

This is just an example and of course, savings will vary from one installation to another, but for the sake of the explanation, let’s assume that the business we are looking at is being charged a kVA penalty for energy usage. This penalty is charged at 37.57 cents per day per kVA (kVA is kilovolt-ampere and is the unit of apparent power. kVA is used for measuring the power consumption of non-resistive equipment such as motors, computers and most non-incandescent lighting).

The equation is this:

If we assume that the site in question is operating at a 1000kW load at a 0.75 lagging factor – and remember, we want unity, or a score of 1 – we need to improve things, say to a lagging factor of 0.95, which is a good compromise between potential savings, equipment costs and equipment lifespan.

1000kW load at a lagging factor of 0.75 = 1333kVA
1000kW load at a lagging factor of 0.95 = 1053kVA

The difference is 280kVA. This means that in our example, the plant is drawing 280kVA per day from the supplier that it doesn’t need!

At 37.57 cents per kVA, it is costing the business $105.20 per day. Across a year, that represents an unnecessary and wasteful expense of almost $39,000!

The average 300kVAr power factor correction system costs around $36,000 meaning it would take less than 12 months for a business to pay it off and thereafter, enjoy the daily saving of $105.20 for the life of the system.

We take care to monitor the running costs of our business and we’re happy to help you identify ways to reduce the energy costs of yours.

Got a question for us?

Please contact us if you have any enquiries for your commercial or industrial installations.