Analysisinterregional-transfer

Interregional transmission can increase reliability while reducing costs and emissions in the US

Nature Energy (Springer Nature)Juan Ramon L. Senga, Audun Botterud, John E. Parsons, S. Drew Story, Christopher R. Knittel18 Dec 2025all-rights-reservedRead the original

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This two-page Nature Energy policy brief compares two ways of setting interregional electricity transfer requirements for the US grid. A uniform 30 percent requirement applied to every region spreads new transmission broadly across the country and delivers an average reduction in outages of about 39 percent, alongside an estimated saving of 480 million dollars a year in system cost and 43 million metric tons of carbon emissions. A region-specific, cost-optimised approach performs considerably better on both measures, cutting system costs by around 2 billion dollars a year and emissions by 71 million metric tons — but it concentrates lines in the central United States. The brief's framing is that uniform requirements do improve reliability, at the price of forgoing much larger gains available from tailoring requirements to regional conditions.

Contested

The equity-versus-efficiency comparison depends entirely on the modelling assumptions behind each scenario, which a two-page brief does not set out.

Quotation

"This uniform requirement could reduce total system cost by US$480 million per year and carbon emissions by 43 million metric tons, respectively."

Nature Energy (Springer Nature) · all-rights-reserved · Read the original

All rights reserved. Only this short quotation is reproduced here.

The MyGreenSuit briefing

Commentary by MyGreenSuit, not the words of Nature Energy (Springer Nature).

Housekeeping first: this is a two-page policy brief, not the study. If you are going to lean on the modelling, find the underlying paper.

The result is a clean statement of a tradeoff usually argued about without numbers. A uniform 30 percent transfer requirement applied everywhere cuts outages by about 39 percent on average and saves roughly $480 million a year. Letting a cost optimiser choose instead saves around $2 billion a year and cuts four times more carbon — but it puts the lines where the economics point, which is the central US, and leaves several regions no better off.

Roughly four times the benefit, delivered to fewer people, through communities that did not choose to host it. That is the actual question, and it is a political one rather than a technical one — which is precisely why an optimiser should not be the thing answering it.

The version worth writing is not "interregional transmission is good." It is that the cheapest grid and the fairest grid are different grids, federal policy has never said which one it is buying, and the places the lines would cross have not been asked.

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