A single phase grid correction system for correcting the power factor of an electrical power grid (15, 25, 65), said grid (15, 25, 65) having an electricity supply (11, 61a, 61b), at least one transmission line connecting said supply to a distribution node (16, 66), a number of feeder lines (19, 19a, 19b, 19c, 20, 21, 28, 28a, 28b, 28c) radiating from the node (16, 66), a plurality of consumers connected to each feeder line (19, 19a, 19b, 19c, 20, 21, 28), said consumers each having individual premises with a single phase consumer electrical panel therein for receiving power from the feeder line, said system comprising: a capacitor bank connected to the panel of at least a plurality of said consumers, each capacitor bank being located at a consumer's premises, and a remotely controlled switch connected to said capacitor bank for connecting or disconnecting the capacitor bank from the feeder line (19, 19a, 19b, 19c, 20, 21, 28, 28a, 28b, 28c), said remotely controlled switch including a receiver for receiving instructions for connecting the capacitor bank to or disconnecting it from the feeder line (19, 19a, 19b, 19c, 20, 21, 28, 28a, 28b, 28c) and for operating the switch according to such instructions, said capacitor bank and remotely controlled switch being housed indoors inside the relevant consumer's premises proximate to or within said electrical panel; characterised in that: the system has a utility operator, the utility operator having a controller for sending signals to cause selected capacitor banks to be connected to or disconnected from the grid (15, 25, 65), wherein said controller includes a computer programmed to compare circumstances existing at the time when the switches are to be operated with circumstances at prior times and for locating similar circumstances which existed at one or more prior times, and for determining the power factor correction which was provided at such prior time or times and for then using such information to determine the number and distribution of capacitor banks which if connected to the grid (15, 25, 65) would supply reactive power sufficient to correct the power factor of the grid (15, 25, 65) to a selected value, and for then switching on the required number of capacitor banks at the locations as determined by said computer. a capacitor bank connected to the panel of at least a plurality of said consumers, each capacitor bank being located at a consumer's premises, and a remotely controlled switch connected to said capacitor bank for connecting or disconnecting the capacitor bank from the feeder line (19, 19a, 19b, 19c, 20, 21, 28, 28a, 28b, 28c), said remotely controlled switch including a receiver for receiving instructions for connecting the capacitor bank to or disconnecting it from the feeder line (19, 19a, 19b, 19c, 20, 21, 28, 28a, 28b, 28c) and for operating the switch according to such instructions, said capacitor bank and remotely controlled switch being housed indoors inside the relevant consumer's premises proximate to or within said electrical panel; characterised in that: the system has a utility operator, the utility operator having a controller for sending signals to cause selected capacitor banks to be connected to or disconnected from the grid (15, 25, 65), wherein said controller includes a computer programmed to compare circumstances existing at the time when the switches are to be operated with circumstances at prior times and for locating similar circumstances which existed at one or more prior times, and for determining the power factor correction which was provided at such prior time or times and for then using such information to determine the number and distribution of capacitor banks which if connected to the grid (15, 25, 65) would supply reactive power sufficient to correct the power factor of the grid (15, 25, 65) to a selected value, and for then switching on the required number of capacitor banks at the locations as determined by said computer. the system has a utility operator, the utility operator having a controller for sending signals to cause selected capacitor banks to be connected to or disconnected from the grid (15, 25, 65), wherein said controller includes a computer programmed to compare circumstances existing at the time when the switches are to be operated with circumstances at prior times and for locating similar circumstances which existed at one or more prior times, and for determining the power factor correction which was provided at such prior time or times and for then using such information to determine the number and distribution of capacitor banks which if connected to the grid (15, 25, 65) would supply reactive power sufficient to correct the power factor of the grid (15, 25, 65) to a selected value, and for then switching on the required number of capacitor banks at the locations as determined by said computer.