High Level

A peer‑reviewed study from Lawrence Berkeley National Laboratory finds high, geographically balanced market value for additional transmission capacity, especially across regional seams, with much of that value concentrated in a small share of peak hours. In the same week, a ratings‑agency analysis warns that newly expanded 50% import tariffs on steel, aluminum and copper could increase materials costs, slow some transmission projects, and test regulators’ willingness to allow full pass‑through to ratepayers.

Full View

Study quantifies high, concentrated market value for interregional and cross‑interconnect transmission
What happened: A Nature Communications paper analyzing 2012–2022 wholesale price data estimates a median energy‑market value of $116 million per GW per year for added transfer capacity, with cross‑interconnect and interregional links showing the highest value. The authors find that 5% of hours account for at least 45% of value and that value‑to‑cost ratios exceed 4 for all evaluated cross‑interconnect projects.
Who did it: Researchers at Lawrence Berkeley National Laboratory.
Why they did it: To ground transmission planning in observed market outcomes and identify when and where transmission delivers the greatest economic value.
Stakeholder views: The authors write that “additional transfer capacity between regions would have been especially valuable, with a median value of $116 million per GW per year,” and that benefits are often balanced between regions.
What happens next: Planners and regulators may use these empirical benchmarks to validate models, with particular focus on interregional seams where value‑to‑cost ratios are strongest. The results also underscore the “insurance value” of transmission during a small set of volatile hours.
Sources:
Nature Communications. “Electric transmission value and its drivers in United States power markets.” August 28, 2025. https://www.nature.com/articles/s41467-025-63143-5

Analysts warn 50% metals tariffs could raise grid project costs and slow some transmission development
What happened: Morningstar DBRS reported that the 50% import tariffs on steel, aluminum and copper may raise materials costs that make up 20%–30% of typical transmission project budgets, complicate procurement of transformer‑grade electrical steel, and pressure utility credit metrics. Utility Dive summarized that “some marginal projects… may no longer generate a positive net present value” once tariff cost increases are included.
Who did it: Morningstar DBRS, reported by Utility Dive.
Why they did it: To assess how expanded tariffs could affect utility capital programs, rate recovery, and credit quality.
Stakeholder views: Morningstar DBRS writes that the 50% tariffs “directly threaten the ambitious agenda to upgrade and expand the U.S. power grid.” Utility Dive notes commissions may stretch recovery periods or cap rates to manage bill impacts.
What happens next: Expect case‑by‑case regulatory scrutiny of transmission cost recovery, more use of cost‑containment and alternative delivery strategies, and potential schedule adjustments where supply chains tighten.
Sources:
Utility Dive. “Import tariffs could slow transmission development, drive up utility costs: Morningstar.” August 26, 2025. https://www.utilitydive.com/news/import-tariffs-transmission-development-utility-costs-morningstar/758601/
DBRS Morningstar. “The Tariff‑Era Grid: A New Cost Reality for U.S. Regulated Utilities.” August 25, 2025. https://dbrs.morningstar.com/research/461025
Reuters. “U.S. hikes steel, aluminum tariffs on imported appliances, wind equipment and more.” August 19, 2025. https://www.reuters.com/business/us-hikes-steel-aluminum-tariffs-imported-appliances-railcars-ev-parts-2025-08-19/

What’s the So What?

The empirical record now says the quiet part out loud: interregional transfer capacity is worth a great deal, most of the time to both sides of the seam, and especially in the rare hours when the system strains. That is the kind of benefit profile—systemic, bi‑directional, insurance‑like—that Order 1920 asks planners to surface and allocate. The Berkeley Lab study gives commissions and RTOs an evidentiary basis to justify seams projects that traditional production‑cost models may undervalue, and it strengthens the case for DOE to steer NIETC designations at the most congested seams.

At the same time, a tariff‑driven cost shock cuts the other way. If materials inflate 20%–30% of project budgets and transformer lead times tighten, economic portfolios that easily cleared benefit‑cost thresholds last year may now sit on the margin. Morningstar’s signal to regulators is clear: bill impacts matter, and commissions may stretch recovery or cap rates rather than green‑light instant pass‑throughs. That creates timing and liquidity risk exactly when long‑lead transmission needs to move from paper to steel.

The policy task is therefore twofold. First, use Order 1920’s expanded benefits framework and the paper’s empirical metrics to capture the concentrated, cross‑seam value that shows up in the hardest hours. Second, actively manage cost and supply risk—standardize conductor and tower specs, lock in framework agreements for electrical steel and transformer cores, and stage portfolios so near‑shovel‑ready projects do not stall. Expect the strongest cases to be interregional seams with balanced flows and documented congestion rents; those are where benefit‑cost resilience is most likely to survive the tariff era.

Bibliography

Nature Communications. “Electric transmission value and its drivers in United States power markets.” August 28, 2025. https://www.nature.com/articles/s41467-025-63143-5
Utility Dive. “Import tariffs could slow transmission development, drive up utility costs: Morningstar.” August 26, 2025. https://www.utilitydive.com/news/import-tariffs-transmission-development-utility-costs-morningstar/758601/
DBRS Morningstar. “The Tariff‑Era Grid: A New Cost Reality for U.S. Regulated Utilities.” August 25, 2025. https://dbrs.morningstar.com/research/461025
Reuters. “U.S. hikes steel, aluminum tariffs on imported appliances, wind equipment and more.” August 19, 2025. https://www.reuters.com/business/us-hikes-steel-aluminum-tariffs-imported-appliances-railcars-ev-parts-2025-08-19/