Back in the 1880s, that question generated an all-out current war between two geniuses. On the one side, Thomas Edison pushed that direct current was safer and would cause less hazard of electrocution. However, it proved to be cheaper and easier to transmit the power of alternating current over long distances. This was the stance of Edison’s competitor, Nikola Tesla.
1. More Power
Probably the biggest advantage of AC over DC is that you can generate much more power from AC than DC. Alternating current is generated by large turbines. Direct current normally comes from batteries or sometimes from solar panels. Solar panels large enough to power entire cities would take huge amounts of land. Batteries use chemical reactions to produce electricity. Producing a huge battery would be expensive and impractical. Large turbines can be easily built and powered using steam, nuclear or hydraulic power.
2. Long Distance Transmission
The ability to generate higher voltages with AC translates into the ability to transmit that power over longer distances. Alternating current is generated at power stations and transmitted through power lines to substations that can boost AC and keep it going farther distances.
In some operations, direct current may be preferred. However, it is easy to convert AC to DC by using simple transformers. It is much more difficult and costly to convert DC to AC.