Flossi is on the Line
Comprehensive Analysis of the Transmission Grid in the Southeast U.S.
The transmission grid in the southeastern U.S. is a critical part of the Eastern Interconnection, one of the two main electrical grids in the continental U.S. It spans multiple states, connecting power plants with homes and industries. This region has a diverse mix of power sources, including fossil fuels (coal, natural gas), nuclear, hydroelectric, and, increasingly, renewable energy like solar and wind.
Key entities responsible for grid management in the region include:
1. Tennessee Valley Authority (TVA): A federal entity that plays a significant role in electricity generation and transmission in the Southeast, particularly in Tennessee and parts of surrounding states. TVA manages an extensive network of transmission lines and provides power across its service area, utilising hydroelectric, nuclear, and fossil-fuel power plants.
2. Southern Company: One of the largest utilities in the Southeast, Southern Company operates in multiple states, including Georgia, Alabama, Mississippi, and Florida. It owns and operates an extensive network of transmission lines and has been transitioning toward cleaner energy, though it still heavily relies on natural gas and nuclear power.
3. Duke Energy: Operating primarily in North Carolina, South Carolina, and parts of Florida, Duke Energy manages a large transmission grid and supplies power to millions of customers. It has been investing in grid modernisation and increasing renewable energy sources, such as solar power.
Key Components of the Southeastern Grid:
- Generation Mix: The Southeast’s generation mix is dominated by natural gas and nuclear power, with coal declining steadily due to economic and environmental factors. Hydroelectric power, mainly managed by TVA, also plays a significant role, while solar energy has been expanding, particularly in Florida, Georgia, and North Carolina.
Transmission Infrastructure: The Southeast’s transmission infrastructure is composed of high-voltage lines that span thousands of miles. These lines move electricity from power plants to distribution centres and end users. The region’s grid connects to other parts of the Eastern Interconnection, ensuring the ability to import or export electricity during peak demand or outages.
- Reliability and Challenges: Regional Transmission Organizations (RTOs) and Independent System Operators (ISOs) manage the grid's reliability. However, the Southeast is unique in that much of its grid is managed by vertically integrated utilities like TVA, Southern Company, and Duke Energy, which operate outside RTOs. This limits some aspects of competition but allows for greater control over grid reliability. The region faces challenges related to ageing infrastructure, increasing energy demand, and the integration of renewables.
- Renewable Energy Integration: There is growing interest in expanding renewable energy in the Southeast, particularly solar power. States like Florida and North Carolina are becoming leaders in solar capacity, with utilities investing in solar farms and grid upgrades to accommodate intermittent renewable energy sources. However, the Southeast still lags behind other regions in wind energy due to geographic and regulatory factors.
Emerging Trends and Grid Modernization:
1. Grid Resilience and Modernization: With the rise of extreme weather events, such as hurricanes, grid resilience has become a critical issue in the Southeast. Utilities are investing in grid hardening measures, such as burying transmission lines and upgrading substations to withstand extreme conditions. Efforts to modernise the grid also focus on incorporating intelligent grid technology, which improves the ability to monitor and respond to power outages and disruptions in real time.
2. Distributed Energy Resources (DERs): The adoption of distributed energy resources like solar panels and battery storage is increasing. Utilities are working to integrate these resources into the transmission system without destabilising the grid, focusing on improving the flexibility and responsiveness of the power supply.
3. Energy Transition: The Southeast has been slower to adopt renewable energy than other parts of the U.S., but this is changing. Utilities are increasingly investing in solar, and there is growing pressure to transition away from coal and reduce carbon emissions.
Regulatory Landscape:
The Southeast's regulatory environment is distinct because most utilities are vertically integrated and do not operate within RTOs or ISOs, meaning utilities often own both the generation and transmission infrastructure. This structure provides stability and allows for coordinated investments but limits market competition. Regulatory oversight is provided by state-level Public Service Commissions (PSCs), which approve utility rates and investments.
