Three-Phase vs. Single-Phase

Define $P_1(t)$ as the instantaneous power dissipated in Case 1, and $P_2 (t)$ as the total instantaneous power dissipated in Case 2 (in all three circuits combined).

$P_{1A}$ is the average value of $P_1 (t)$ , and $P_{2A}$ is the average value of $P_2 (t)$ (averaged over an integer number of cycles).

$P_{1P}$ is the maximum instantaneous value of $P_1 (t)$ , and $P_{2P}$ is the maximum instantaneous value of $P_2 (t)$ .

What is $(P_{1A} + P_{2A} + P_{1P} + P_{2P})$ ?

Bonus: What are the implications for building large generators which source huge amounts of power?