Transmission 101

Transmission refers to the high-voltage “interstate highway” system of the electric grid that moves large amounts of electricity over long distance to areas where people and businesses use it.

Quick Facts:

1. Transmission is not the same as distribution. Transmission is high-voltage, long-distance. Distribution is the local, lower-voltage power lines that bring electricity to homes and businesses.

2. In Arkansas and across the country, there isn’t enough transmission to meet rising energy demand. That’s why “transmission planning” and major interregional upgrades are so important. A June 2025 report finds that well-planned, high-capacity transmission can deliver up to $4.70 in customer benefits for every $1 invested.

3. Arkansas electric transmission is managed by two Regional Transmission Operators (RTOs):

   1. Midcontinent Independent System Operator (MISO) oversees Entergy Arkansas’s territory.

   2. Southwest Power Pool (SPP) manages everything outside of Entergy Arkansas’s territory.

4. MISO and SPP are responsible for coordinating power flow, ensuring grid reliability, and facilitating electricity markets across Arkansas and neighboring states.

5. RTOs must comply with federal cost allocation rules to ensure project beneficiaries bear their share. Load-serving customers and utilities pay based on benefits received. Generators or developers pay most costs associated with connecting new projects.