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AC Power Vs. DC Power for Distribution

Both alternating current (AC) and direct current (DC) are two types of delivery systems for electrical power. Proponents of either system famously competed in the "Battle of the Currents" in the late 19th century to determine which type of current would dominate on the American market. While both AC and DC are still used today for various functions, AC ultimately showed itself to be the better system for widespread distribution throughout the country.

DC Current
- Thomas Edison invented direct current in the late 19th century. Direct current sends electrons in one continuous direction, which is why Edison called it direct current. While direct current is no longer used for long distance power generation, it still has many uses. Batteries operate using direct current, as the electrons that provide energy from batteries flow in one direction. Many types of electronics, such as computers, use direct current and require a special AC to DC adapter in order to use electricity from typical electrical outlets.
AC Current
- The scientist Nicola Tesla invented alternating current, and a man named George Westinghouse heavily championed it in the United States. Unlike direct power, alternating current sends electrons in both directions. The electrons alternate between going forward and then going backward, which is why the current is called alternating current. In alternating current, the electrons do not travel significant distances, and as a result very little energy is lost due to friction.
Distance
- One of the primary reasons why AC is better than DC is the distances AC travels without losing noticeable amounts of energy. A DC line has a maximum range of approximately half a mile, so in order to use DC current in your home you would need a DC power station within a half mile of your house. Alternating current, on the other hand, can send energy hundreds of miles because the electrons themselves only travel a small distance before passing on the energy to other electrons. This greatly expands the effective range of electricity.
Cost
- Alternating current is cheaper in many ways than direct current. Firstly, alternating current loses less energy, meaning less energy has to be produced overall. Second, unlike DC current which requires very high quality copper wires to transmit effectively, AC can use much cheaper wires because losing power is less of a concern. Finally, AC power requires much less infrastructure investment because it requires substantially fewer power stations to transmit electricity.

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