an interconnected group of lines and associated equipment for the movement or transfer of electric energy between points of supply and points at which it is transformed for delivery to customers or is delivered to other electric systems
Pros
Allows for cost-effective market operation and access to a diverse generation supply.
Cons
A single disruption can have a big service impact. It can be problematic to agree on who should pay for system improvements or additional capacity.
Real Talk
Transmission systems will be needed to deliver energy produced by remotely sited solar and wind to densely populated areas. The keepers of the system, i.e. FERC and the authority having ISO/RTO, need to enable and protect consumer access to these systems.