Alternating current is cheaper to generate and has fewer energy losses than direct current when transmitting electricity over long distances. Although for very long distances (more than 1000 km), direct current can often be better.

Which one is better AC or DC?

DC power is significantly more energy efficient than AC power. DC motors and appliances have higher efficiency and power to size characteristics. ... The greater efficiency resulting from recent developments in DC converter technology allows improvements in electricity delivery over long distances.

Why are alternating currents better than direct currents?

But there was one problem. Direct current is not easily converted to higher or lower voltages. ... Alternating current reverses direction a certain number of times per second -- 60 in the U.S. -- and can be converted to different voltages relatively easily using a transformer.