A new Brattle Group report spotlights the Southeast as the only major U.S. region without thorough transmission planning and recommends it develop a portfolio of projects or risk failing to keep up with the times.
The April 2 report — prepared for the Carolinas Clean Energy Business Association, Clean Energy Buyers Association and the Southern Renewable Energy Association (SREA) — concludes “the status quo approach for planning and building the future region-wide Southeast grid is insufficient” to meet load growth and growing reliability risks brought on in part by weather extremes.
“Transmission development today is driven by utilities planning their systems in isolation, focusing primarily on their service areas (or in some cases the joint network within a state) instead of taking a broader, regional approach to grid expansion,” authors J. Michael Hagerty, Peter Heller and Evan Bennett write. They asked Southeastern utilities to “think larger and embrace regional solutions that supplement utility-specific upgrades.”
The Brattle report says a bolder planning approach is a must, especially since meaningful regional transmission projects have failed to materialize for more than a decade through the utility-created Southeastern Regional Transmission Planning Process (SERTP). It concludes that recent Southeast transmission projects conceived separately by utilities or even small groups of utilities such as the Carolinas Transmission Planning Collaborative and the Georgia Integrated Transmission System are lacking.
“Without a regional, forward-looking strategy that maximizes the value of transmission investments, Southeast utilities risk inefficiently investing in lower-value local reliability projects within their respective systems, resulting in rising transmission rates without achieving the greatest return on their transmission investments,” the authors said. “Instead of maintaining existing systems, utilities should prioritize regional upgrades that supplement necessary local reliability upgrades and support a reliable grid, new energy generation and long-term load growth.”
In an April 2 webinar to review the report, Hagerty pointed out that the Southeast’s big players — Southern Co., Duke Energy, Louisville Gas & Electric and Kentucky Utilities Co. — have quadrupled spending on local transmission needs since the early 2000s, when they collectively spent about $500 million per year. Now, those utilities have spent nearly $2 billion annually in the past five years. He and the two other report authors said the spending mostly was to replace aging infrastructure, connect new generation and support “moderate” load growth.
The report warned that conducting transmission planning largely in isolation leads to missing out on opportunities to build larger, more cost-effective projects and their resilience benefits.
The report said a $5 billion investment in three 500-kV lines that SERTP evaluated in 2024 could save $2.9 billion conservatively on production costs, $3.3 billion on load diversity and $1.6 billion on resilience benefits. However, the report said SERTP adopted an “overly narrow view of cost savings” and found no benefits of increased transfer capability among Duke Energy, Southern Co. and the Tennessee Valley Authority due to the three major upgrades.
However, the report said the Carolinas Transmission Planning Collaborative’s in-progress Multi-Value Strategic Transmission Study could show promise for the two states and be replicated on a larger scale in the region.
‘Lifelines’ for SERTP
SREA Executive Director Simon Mahan said the Southeast’s unprecedented projected load growth means new transmission “lifelines” are necessary. Without them, the Southeast grid risks higher energy costs and reliability disruptions.
“At the end of the day, lives are on the line without enhanced transmission solutions,” Mahan said.
Lead author Hagerty said by 2035, the Southeast’s electricity demand is expected to rise by 25% to 21 GW. He and the other authors noted that amount is similar to a doubling of New York City’s demand, and said the Southeast will need regionally planned transmission to connect the estimated 80 GW in new generation to keep up while maintaining reliability.
Hagerty said SERTP planning is inadequate to take on the modern needs of the Southeastern grid. The report criticized SERTP’s planning structure — composed of 10 sponsor utilities from 12 states with no independent staff — as too narrow to be effective. Mahan said the process, which isn’t open to the public and state regulators aren’t involved in, is mysterious.
Hagerty also said SERTP’s single model doesn’t produce a realistic future resource mix and the group should reach out to states to get a better view of future generation.
“The proof is in the pudding,” Hagerty said, adding that over the last 11 years, SERTP hasn’t proposed a single regional upgrade. He said the process is “unlikely to support the investment needed in the Southeast” as demand rises and that a lack of regional planning would correlate with higher costs, delays in serving new load and reliability troubles as more extreme weather stresses the grid.
Carolinas Clean Energy Business Association Executive Director Chris Carmody said Southeastern utilities are building “very tall silos” of new generation that could burden ratepayers with higher costs.
“Without transmission, it’s going to be dressed up with nowhere to go,” Carmody joked. He said the Southeast should adopt Eisenhower’s attitude when trying to get the interstate highway system built.
Carmody added that “one weather event after another” seems to strike the Southeast, and regional transmission could stand in for hard-hit areas that lose service on lines.
The report said FERC’s Order 1920 could provide the Southeast with an opportunity to create proactive planning that exceeds the federal rule’s parameters. SERTP could use the multi-value and scenario-based planning that exists in other planning areas in the country and incorporate load forecasting to land on portfolios of transmission solutions or even interregional projects, it said.
Hagerty said the Southeast should view Order 1920 as a “floor” and go beyond the rule’s requirements for an even more dependable grid.
The Brattle report asked SERTP to shed more light on its planning and share input assumptions, study results and project costs publicly. It also recommended SERTP adopt a “beneficiary pays” method for cost allocation of regional lines.
Carmody said Southeast utilities should ignore the instinct to build up their islands and work together to avoid leaving their systems vulnerable or missing out on a new manufacturing plant. He said utilities can either choose to continue driving a 1950s Rambler or “accept that that’s not going to be safe or efficient for us” and make investments.
“Proactive transmission planning supports a growing economy,” Clean Energy Buyers Association’s Katie Southworth added.
SREA previously criticized SERTP’s planning and said Order 1920 could nudge SERTP “away from a process that studies regional transmission lines to justify not building them.”
SERTP did not respond to RTO Insider’s request for comment on whether there is room for improvement in its regional planning or its still-developing plans to comply with Order 1920.
Recent calls for stronger transmission planning in the Southeast also extend to MISO South.
Stakeholders at MISO’s Board of Directors Week in March lined up during a public comment period to ask the RTO to engage in long-term planning in the RTO’s South region. While MISO has designated two long-term portfolios at a combined $32 million in the Midwest, grid planners have yet to prescribe any long-term projects for the South region. (See MISO Fields Divergent Calls for Stronger South Planning, IRA Reversal in Tx Futures.)