At the advent of the 20th century, there was a war for which form of electricity would win in the race for modern industry. Tesla championed alternating current (AC) while Edison championed direct current (DC). In spite of reactive power problems, AC won because generated power could be centralized in bulk and transmitted over long distances through the use of transformers and transmission lines. Critical to this was the use of transformers for minimizing transmission losses through upward voltage conversion. DC lost because there was no viable way of stepping up/down DC voltages. So AC won round 1. Roughly 50 years later, problems arose that AC could not solve. These include the how to interconnect 2 asynchronous AC systems, integrate variable frequency AC wind power into the fixed frequency AC electrical grid, transmit AC power through underwater cables with large capacitive reactance and transmitting AC power over long lines with large inductive reactances. For all of these problems, DC was the solution, hence high voltage direct current (HVDC) transmission became mainstream. What enabled DC conversion was power electronics. So DC won round 2. Now there is intense research for what the future grid should look like given the need to decarbonize modern industry and improve end-use energy efficiency. So the truce is over and round 3 is about to start.