Reactive power charge at time of survey – the bill for this site was not specific about unit charges for kVArh, but instead just gave the total reactive power charge. This charge would have been based upon not achieving an average power factor of 0.95 and averaged £250.00 per month.
Available Supply Capacity (ASC) charge – £1.59 / kVA / month.
During our site survey the following load vectors were recorded:
kVA – 637
kW – 452
PF – 0.71
kVAr – 448
From the metering information the estimated maximum demand load vectors were as follows:
kVA – 867
kW – 650
PF – 0.75
kVAr – 573
In order to correct the maximum demand condition to a more economical level of 0.97, 400 kVAr of power factor correction was offered.
With the above capacitors connected the maximum demand condition was predicted to be as follows:
kVA – 673
kW – 650
PF – 0.97
kVAr – 173
The reduction in maximum demand predicted = 867 – 673 = 194 kVA
Potential annual savings
From the above information, the following savings were calculated:
Excess reactive power – on average the client was receiving £250 / month in reactive power charges. By installing the equipment recommended this charge was virtually eliminated as an average power factor greater than 0.95 would be maintained. Achieving annual savings of £250 x 12 = £3,000.
Available supply capacity – the reduction in maximum demand of 505 kVA represents an annual available supply capacity saving of 194 x 1.59 x 12 = £3701.52
Total potential annual savings =
Installed cost of equipment recommended
The total installed cost of the equipment recommended was £8499.00
Payback period of equipment
From the cost of the equipment and the potential annual savings, the payback period of the equipment was calculated as approximately 15 months.
Result of survey
The equipment recommended was installed. The reactive power charges were eliminated and the client is presently evaluating their reduced maximum demand before re- negotiating their available supply capacity.
THIS INSTALLATION OF POWER FACTOR CORRECTION AT THIS PACKAGING COMPANY ACHIEVED SAVINGS OF ALMOST £7000 PER ANNUM, ACHIEVING A PAYBACK PERIOD OF ONLY 15 MONTHS.