Industrial supply issues bring a new relevance to power factor correction, says Stephen Joyce, power quality business manager at ABB’s Power Grids business in the UK, in this sponsored post.
There is a tendency in UK industry to think that the disappearance of reactive power charges from itemised energy bills has killed the argument for installing power factor correction (PFC) equipment. But that view doesn’t reflect the full story. Because as the investment cost and leadtimes for obtaining new power supplies from electricity suppliers continue to escalate then power factor has taken on a new relevance.
Power factor (PF) is the ratio of ‘real’ power that is used by businesses (in kW) to the ‘apparent’ power that needs to be produced (in kVA). A power factor equal to 1 (unity) demonstrates that power is being produced and consumed most efficiently, and all UK utilities aim for a minimum of 0.95.
Many UK industrial and commercial consumers have low power factors (well below 0.8) due to their extensive use of lightly loaded electric motors, pumps, fluorescent lighting and other inductive equipment. The impact of low power factor is that more apparent power needs to be produced to meet the real power requirement of businesses. Ultimately, this imposes costs on society, such as the need for more generation capacity as well as additional transmission and distribution network capacity, and increased greenhouse gas emissions.
There is a relatively simple solution available in the form of PFC equipment, such as automatic capacitor banks. In fact, the BEAMA Capacitor Manufacturers Association (BCMA) has estimated that in the UK 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.
Even so, many manufacturing sites are still operating close to their 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. And that capacity is there ready to use, right now.
To quote just one example, we recently helped a small manufacturing company that was planning to expand production. But they had been quoted £150,000 to construct the additional power infrastructure they needed, combined with the disruption involved in digging up local roads. Our survey established that the site was operating at a power factor of 0.57. Installing PFC soon restored this to 0.95, effectively freeing up an extra 81 A to more than meet the demand of the new facility.