Electricity is transmitted at very high voltages (e.g., 66 kV to 765 kV) to minimize power loss over long distances. According to the laws of physics, a higher voltage allows for a lower current to transmit the same amount of power. Since power loss is proportional to the square of the current (I²R), reducing the current significantly reduces energy waste. Once the electricity reaches a local substation, its voltage is "stepped down" by transformers to a safer, lower level (e.g., 220V, 400V) suitable for consumer use in the distribution network.