Answer: The primary cause of energy loss in power transmission lines is resistive heating, often referred to as the Joule effect. As electric current flows through a conductor, the conductor's natural resistance converts some of the electrical energy into heat, which dissipates into the environment. This loss is proportional to the square of the current (P = I²R), meaning even a small increase in current can lead to a significant increase in lost energy.

Other contributing factors include:

• Corona Discharge: At very high voltages, the air around the conductors can become ionized, leading to a visible glow and audible hissing sound, which represents a loss of energy.

• Inductive and Capacitive Losses: Alternating current (AC) creates changing magnetic and electric fields that can also cause minor energy losses.

To combat these losses, power is transmitted over long distances at extremely high voltages. This allows the current to be kept low, thereby minimizing resistive losses. Using high-quality, low-resistance conductors and efficient equipment is essential for maximizing the power delivered and reducing waste.