Why DC May Replace AC (2019)
There is an interesting effect with AC distribution that leads to the statement &quot;the amount of power produced must balance that consumed&quot; that you sometimes hear.<p>On first thought this is a ridiculous statement: voltage is a measure of potential energy after all.  If load is reduced, the voltage just hangs there and less power will be consumed.<p>But with AC distribution what you have is essentially a large rotating machine.  The more power you put into it, the faster it spins.  When you connect a generator to the grid, you phase match the AC waveforms, connect it, then start pushing the grid faster to inject power.<p>So the statement is true.  If the load is too low, the frequency starts to go up.  But it&#x27;s also not true.. if each generator independently self limits the frequency, we would be back to the potential energy situation.  But power plants want to push power into the grid- this is how they earn money.<p>So some plants self regulate and some do not, see:<p><a href="https:&#x2F;&#x2F;www.e-education.psu.edu&#x2F;ebf483&#x2F;node&#x2F;705" rel="nofollow">https:&#x2F;&#x2F;www.e-education.psu.edu&#x2F;ebf483&#x2F;node&#x2F;705</a><p>Ones that self regulate get to charge a premium for their unused capacity.<p>Even with DC only, you would be in the same situation.  A power plant wants to make money, so it will want to push power into the grid, which for DC means pushing the voltage up.