As such spinning reserve (energy) can be reduced, not the energy saving. As improved power factor, will reduced the current required, for same load, will reduced the (I2R) losses and improves the system(distribution) efficiency. Energy saving can be obtained by reduction in active power, due to improved power factor, after instoleing the capacitance bank, in sub station.....

If the Capacitor (C) had an Internal Inductance (L), you cannot generate the Current (I) more than the value given by  I = V* SQRT(C/L), where V is the Original Voltage you used for the capacitor charging, and SQRT means  Square Root.

dear

Power factor is a measurement of electrical system efficiency. Many utilities have a

power factor penalty built into their rate structure to penalize users with a low power

factor reading in their electrical system. To improve the power factor, the most

common solution is to install a capacitor system.

Regarding energy save from a powe factor correction strategies, you should consider  2 aspects. First, i2r loss above installation point of capacitor along the path of current flow is surely reduced. This can be calculated for a given example with availables data. However, the voltage at installation point may be slightly increase thus the power utilization by various loads trend to increase, which is difficult to evaluate in term of efficiency or expense.

Energy saving with capacitor is possible or not. Is clearly explained in this link and report of Schneider Electric.

Best of Luck for your research.

http://static.schneider-electric.us/docs/Power%20Management/Power%20Quality%20Correction%20Equipment/5800DB1201.pdf

http://www.reliableplant.com/Read/13339/power-factor-correction

http://www.edn.com/electronics-blogs/beyond-bits-and-bytes/4374264/Power-factor-correction-devices--Can-they-really-reduce-your-electricity-bill-

Power capacitors provide many benefits:

• Reduced electric utility bills

• Increased system capacity

• Improved voltage

• Reduced losses

By installing correction capacitors, the consumption of electrical energy can be optimized. How much can you save? That question cannot be answered precisely because much more information is needed.