Transmission Impact Assessment

Investments from the Bipartisan Infrastructure Law (BIL) and the Inflation Reduction Act (IRA) in clean energy and the electric grid are transforming the power sector and saving consumers money. As utilities across the country navigate these changes, transmission has emerged as an essential and fundamental component for connecting both generation resources and loads to the grid. Ultimately, a robust transmission system is required to meet grid needs and support increased activity and load growth associated with data centers, new manufacturing facilities, and electrification. 

In recent years, piecemeal transmission deployment processes focused on meeting incremental reliability needs have struggled to deploy enough transmission to keep up, leading to delays and higher costs. DOE’s Office of Policy’s Transmission Impact Assessment provides insights on how enhancing transmission deployment can reduce costs, improve reliability, and lower pollution.  

The study evaluates the impacts of three scenarios with enhanced transmission deployment. It does not reflect any one specific policy, but instead explores scenarios with enhanced transmission deployment that could be achieved through effective implementation of existing and new policies. Notably, DOE and several other Federal agencies have already taken significant steps to bolster transmission planning and permitting, in addition to investing billions of dollars in new transmission projects through BIL and IRA. This assessment, with a focus on the impacts of policies and actions that enhance transmission deployment, complements other DOE research and analysis efforts to support transmission planning, including the Grid Deployment Office’s National Transmission Planning Study. 

Accelerating transmission deployment can unlock hundreds of billions of dollars in benefits. The report finds that an enhanced transmission deployment scenario that focuses on regional and interregional lines can: 

• Save $320 billion in present-value costs through 2050, by enabling access to low-cost generation and by sharing reliability resources over broader regions.  
• Improve reliability during periods of grid stress through increased interregional power flows, which can lower system costs and decrease the risk of power outages.  
• Reduce cumulative power sector greenhouse gas emissions by 3,420 million metric tons through 2050. 
• Realize $730 billion and $50 billion in climate and health benefits respectively through 2050.  

To assess the possible impacts of recent executive actions in combination with additional policy action, DOE used an advanced planning model that identifies low-cost power sector investment portfolios—the Regional Energy Deployment System (ReEDS) model, developed at the National Renewable Energy Laboratory (NREL).