A report released April 2 by consulting firm Brattle for clean energy organizations makes a strong case for proactive regional transmission planning at the Southeastern Transmission Planning (SERTP).

A report released April 2 by the consulting firm Brattle for clean energy organizations makes a strong case for proactive regional transmission planning at the Southeastern Transmission Planning (SERTP).

Locally focused transmission upgrades have increased 4x in the past five years and will continue to increase with load growth.

As the regional transmission planning entity for the Southeast under the Federal Energy Regulatory Commission (FERC), SERTP is charged with determining the potential for regional transmission to displace local transmission. Local transmission refers to transmission projects, either upgrading existing lines or building new lines, that are wholly within a single utility’s service territory. Regional transmission spans multiple utilities but falls within a single region, one of those regions being SERTP. 

Instead of holistically evaluating the benefits of regional transmission projects, to date, SERTP has simply combined each SERTP utility’s local transmission plan and evaluated, on a short timeframe, whether a regional transmission project would cost less than the sum of local projects. This ignores the potential for regional projects to offset local projects beyond the 10 years that SERTP studies and ignores many other potential benefits of regional transmission. And since each utility resource plan prioritizes local generation and transmission, this restrictive approach to benefits has led to SERTP never recommending a regional transmission project over the last ten years. 

SERTP utilities have spent $1.8 billion annually on local transmission upgrades since 2019, compared to $500 million in the early 2000s. This “bottom-up” approach to transmission is driven by utilities building their own generation and local transmission in a piecemeal fashion to meet system needs, instead of considering the benefits of a long-term transmission plan to accommodate new generation and importing electricity from a neighboring utility. SERTP’s bottom-up approach also does not require a positive benefit-to-cost ratio, while proactive transmission planning would. Brattle’s findings in this report reflect those identified by RMI in their “Mind the Regulatory Gap” report released in 2024, which highlighted regional projects are often only evaluated to meet needs not already met by a local transmission project in a utility resource plan.

Three utilities, Georgia Power, the Tennessee Valley Authority (TVA), and Duke Energy in North and South Carolina, are forecasting they will have 21 GW of new load by 2035. According to Michael Haggerty at Brattle, the $1.8 billion per year in local transmission upgrades will continue to grow as more electric load is added to the Southeast. As the electric grid in the Southeast continues to transform, locally focused transmission will be increasingly inefficient and unsustainable for customers.

Regional transmission planning is more cost-effective for Southeast needs

On the other hand, Brattle used a set of comprehensive benefits when they reviewed SERTP’s 2024 economic study of three new 500 kV lines between Georgia Power, TVA, and Duke Energy in the Carolinas. Benefits included production cost savings (i.e., lower cost electricity), lower interconnection costs for new generation, and less new generation needed to meet system reserves. Unlike the SERTP utilities identifying no benefits, Brattle found net benefits would equal $3 billion ($8 billion in benefits compared to $5 billion in costs).

The report recommends that SERTP adopt a multi-driver, regional-first approach so that planning can be done by evaluating all of the benefits and costs. When this is done effectively, the benefits of regional transmission exceed the costs, saving customers on their bills. For example, Midcontinent Independent System Operator’s (MISO) Tranche 2.1 proactive transmission projects have a cost-benefit ratio of 1.8 to 3.5, meaning each $1 spent on regional transmission provides $1.80 to $3.50 in benefits.

State commissions need to be more involved at SERTP

A changing grid in the Southeast drives several recommendations from Brattle in this report, including more involvement at SERTP from state utility commissions, the primary regulator of utilities. Over the past ten years, commissioners have rarely attended a SERTP quarterly meeting. 

Brattle highlights the Regional State Committee (RSC) at the Southwest Power Pool (SPP) as an example of commissioner oversight of regional planning. The RSC has the authority to file modifications to SPP tariffs at FERC. A similar body should be a goal for improving state commission oversight of SERTP.

In the meantime, commissioners and staff are highly encouraged to join SERTP stakeholders at the April 30 Order 1920 and June 25 Order 1000 meetings, virtually or in person.