DC power cannot be transmitted over long distances. This is the original problem that caused AC to win out.

There are two forms of load, inductive and resistive, and two corresponding types of power, reactive and real. If we use a rowboat analogy, real power can be thought of as the oscillation of the oars back and forth, while reactive power becomes the force of the oar pushing the water. Of course, the oars only push the water in one direction, then they're lifted and repositioned to push again.

In DC power, real and reactive power are indistinguishable. Voltage and current push in one direction all the time. It's only AC power where the rowboat analogy comes into play. So, WHY DO WE USE AC?

Simply, current cannot be made to flow over vast distances. We learned early on that you cannot transmit DC power over much more than a few miles without starting to suffer unacceptable transmission losses (we're not talking a few percent here; trust me on this, there's no solving THIS problem without cheap hot superconductors).

Now, both AC and DC motors require a net current in one direction (inductive load, satisfied by reactive power). But current can't be sent very far. So the solution is capacitors. In areas too far from a spinning generator to receive reactive power from the generator, utility scale capacitors are used to create local reactive power loops, satisfying the inductive load.

Some rubes at this point suggest making all load resistive, by putting capacitors in all your appliances. This is not practical. The people who are opposed to it are the insurance companies and their associates like UL. Capacitors... explode. And big ones require a lot more care than the tiny ones that drive your computer fans.

DC power cannot be transmitted over long distances. This is the original problem that caused AC to win out.

There are two forms of load, inductive and resistive, and two corresponding types of power, reactive and real. If we use a rowboat analogy, real power can be thought of as the oscillation of the oars back and forth, while reactive power becomes the force of the oar pushing the water. Of course, the oars only push the water in one direction, then they're lifted and repositioned to push again.

In DC power, real and reactive power are indistinguishable. Voltage and current push in one direction all the time. It's only AC power where the rowboat analogy comes into play. So, WHY DO WE USE AC?

Simply, current cannot be made to flow over vast distances. We learned early on that you cannot transmit DC power over much more than a few miles without starting to suffer unacceptable transmission losses (we're not talking a few percent here; trust me on this, there's no solving THIS problem without cheap hot superconductors).

Now, both AC and DC motors require a net current in one direction (inductive load, satisfied by reactive power). But current can't be sent very far. So the solution is capacitors. In areas too far from a spinning generator to receive reactive power from the generator, utility scale capacitors are used to create local reactive power loops, satisfying the inductive load.