Complex sentence: Power factor correction may be applied either by an electrical power transmission utility to improve the stability and efficiency of the transmission network; or, correction may be installed by individual electrical customers to reduce the costs charged to them by their electricity supplier.
Split into simpler sentences: Power factor correction may be applied either by an electrical power transmission utility to improve the stability and efficiency of the transmission network. Or, correction may be installed by individual electrical customers to reduce the costs charged to them by their electricity supplier.