an industry term for transmission or distribution utility, load aggregator, power marketer, or other entity that has a contractual or regulatory obligation to sell and/or deliver electric energy to end users.
Pros
Provides a point of control and organizational reliability for transmission system operators.
Cons
Becoming an LSE is a protracted and potentially quite expensive process.
Real Talk
California ISO recently updated the term to include any entity granted authority to serve its own loads (such as Bay Area Rapid Transport or BART), potentially setting up legal and financial implications for communities moving to organize their own energy futures.