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Article Date: 3rd June 2014

ABB Power - Power Factor - It’s Now a Security of Supply Issue

Power Factor Correction - Power Factor - Power Quality Systems

ABB Factory

Colin Green, ABB’s Head of Regulatory Affairs and Technology for the UK, explains why power factor correction has a crucial role to play in ensuring future security of supply.

We often refer to power in terms of the kilowatts (kW) or kilowatt-hours (kWh) produced or consumed within our energy system. Energy policies are also often based around these concepts, whether it is renewable energy support or energy demand reduction. Nevertheless, the importance of power factor is regularly taken for granted or overlooked when considering policy development.

Power factor (PF) is the ratio of “real” power that is used by businesses and households (in Watts) to the “apparent” power that needs to be produced (in Volt-Amps). It is often seen as a measure of electrical efficiency of the energy system. A power factor that is equal to 1 demonstrates that power is being produced and consumed most efficiently. A power factor that falls below 1 shows that power is not being consumed efficiently and that more “wattless” or reactive power is needed.

A power factor below 1 occurs when the wave forms of voltage and current become out of phase with each other.

In general, any process that uses electrical energy to drive motors and pumps will cause the wave form of voltage and current to move out of phase. The greater the phase differences between voltage and current then the lower the power factor. This is important because, in simplified terms, our power generation must meet the requirement for apparent power.

If power factors are low then more apparent power needs
to be produced to meet the real power requirement of businesses and households.
Ultimately, this imposes costs on society – requirement for higher levels of generation capacity, requirement for more transmission and distribution capacity, and additional greenhouse gas emissions.

Power factor correction
Many UK industrial and commercial consumers have low power factors (below 0.8) due to their extensive use of lightly loaded electric motors, pumps, fluorescent lighting and other inductive equipment. For several decades ABB has been supplying power factor correction (PFC) equipment, such as our automatic capacitor banks, to address the impact of low power factors.

There is currently a large installed base of PFC equipment that is significantly improving the efficiency of energy consumption. The BEAMA Capacitor Manufacturers Association (BCMA) estimates that this equipment has removed the need to generate a further 2 terawatt-hours (TWh) of electricity a year and maintains CO2 emissions savings of 1.2 million tonnes.

Freeing up network capacity
Until April 2012, there was an important economic driver for businesses to invest in PFC. This was because many electricity suppliers levied an ‘excess reactive power charge’ – typically in the region of 0.19 to 0.43p/kVArh – on sites with a low PF. And even at these low incentive levels, the typical payback period on PFC equipment was around 1-2 years.

But while these charges have now been removed there can still be compelling business reasons to invest in PFC. For example, there are many manufacturing sites where the existing power network is operating close to its maximum load, so that future expansion would require major investment in new power infrastructure. Yet installation of PFC equipment can often improve the site’s energy efficiency to the point where extra capacity is freed up to cope with new, additional loads using only the existing supplies.

PFC and society
Overall, failure to support power factor improvement has wider societal implications, including an adverse impact on the delivery of the Government’s energy policy aims by:

  • Putting further upward pressure on energy production capacity to meet energy demands
  • Limiting the ability of utility networks to utilise spare capacity for the connection of new businesses or generation to support the development of a low carbon economy;
  • Imposing further direct costs on energy consumers as a whole, we all pay for the increased energy production that will be required to compensate for the wasted power
  • Adding to security of supply pressures at times of peak demands, increasing the risk of blackouts
  • Increasing the indirect costs of wider financial support to ‘green’ our energy system.

It is important to note that some energy saving measures, while reducing kilowatt hour consumption, increase inductive demands and therefore reduce overall power efficiency. This has the potential to undermine some of the energy saving that is achieved as a result of the further deterioration of power factors. ABB is keen to see measures to actively support power factor improvement across the UK energy system.

How can ABB help?
ABB has an extensive portfolio of power factor correction services. These include consultancy to assess site power factor issues and to design and develop the optimum solution. Then, using our advanced PFC equipment, we can deliver a turnkey package and support it throughout a long service life.

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