Energy resilience and reliability are overlapping but distinct concepts. Reliability is a combination of the power grid’s ability to meet demand, and its ability to withstand disturbances. When regulatory bodies enforce energy reliability, they’re looking at those two concepts: adequacy and security.
Resilience goes just a bit further in factoring in the kind of big, external events that could do more than just disturb power but knock out a community or individual’s access entirely. When we talk about resilience, we’re talking about whether or not you can expect power to come out of your outlet, regardless of what time of day it is or what’s happening outside. For the average person reading this, the question of energy resilience is probably an abstract one; you can rely, with near absolute certainty, on the fact that if your refrigerator is plugged in it’s running.