Electricity is transmitted at very high voltages to reduce energy loss during long-distance transport. The power loss in a transmission line is calculated by the formula Ploss=I2R, where I is the current and R is the resistance of the line.

By increasing the voltage (V), the current (I) can be significantly reduced to transmit the same amount of power (P=VI). Since the power loss is proportional to the square of the current, even a small reduction in current leads to a dramatic decrease in wasted energy, which is mostly lost as heat. This makes high-voltage transmission highly efficient for moving large amounts of power over vast distances.