This is a consequence of long lead times for infrastructure projects, overshoot, and the difficulty of predicting the future.
The over-abundance of electricity can be traced to poorly designed deregulation of the industry, which set the stage for blackouts during the energy crisis of 2000-2001.
No longer able to produce as much of their own electricity, they ran up huge debts buying power that customers needed. Blackouts spread across the state.
State leaders, regulators and the utilities vowed never to be in that position again, prompting an all-out push to build more plants, both utility-owned and independent.
Idea: Public policy, which must be revisited/re-evaluated every year, and written alongside stated assumptions (as exhaustive as possible) such that checks can be performed as to if those assumptions still hold true (or are expected to hold true for the time frame in question).