Why were the first public power stations unable to transmit direct current over long distances?

The first public power stations were unable to transmit direct current (DC) over long distances primarily because it was uneconomical to change its voltage at that time.1

In electrical transmission, power loss is proportional to the square of the current multiplied by the resistance of the line. To minimize these losses over long distances, it is necessary to transmit power at very high voltages and correspondingly low current. Because early DC grids could not easily change voltages, they were forced to operate at low voltages and high currents, which resulted in significant energy loss and limited their reach to short distances.2

In contrast, alternating current (AC) systems were adopted because they could easily use transformers to step up voltage for efficient long-distance transmission and step it down for safe use by consumers. While modern technology has since enabled long-distance DC transmission, it remained a significant obstacle for the early power systems of the late 19th century.231