The U.S. Department of Energy has announced two actions to support the expansion of the transmission grid: investing up to $1.5 billion in four specific projects around the country and releasing the final National Transmission Planning Study. 

The $1.5 billion investment from the Transmission Facilitation Program was authorized by the Infrastructure Investment and Jobs Act. DOE is giving the money upfront to four projects, which eventually can sell it to actual users, at which point the department will get its money back to use on future transmission projects, Deputy Energy Secretary David Turk said on a call with reporters Oct. 1.

“Like many things about the clean energy transition, building new transmission is extremely challenging, and it’s also extremely urgent,” Turk said. 

DOE announced the first three lines under the TFP last fall; all three have signed deals with the department, Turk said. In total, the TFP should help build more than 3,000 miles of new transmission by early next decade. (See DOE to Sign up as Off-taker for 3 Transmission Projects.) 

Avangrid Network’s Aroostook Renewable Gateway in Northern Maine will negotiate for DOE for funding of up to $425 million to build the 111-mile project that seeks to link up to 1,200 MW with ISO-NE. The region lacks direct connections with the rest of New England, and the line would help three mature wind projects connect to the market, with the potential for more wind and solar development. 

Invenergy’s Cimarron Link Transmission is negotiating for TFP funds of up to $306 million to build its 400-mile HVDC line running from Oklahoma’s panhandle to Tulsa in the east, opening 1,900 MW of transfer capacity that can deliver wind and solar to load centers.

Pattern Energy’s Southern Spirit Transmission project also is up for negotiations for $360 million to help get the 320-mile, 525-kV HVDC line that would connect ERCOT to the Southeast. The line can ship up to 3,000 MW of renewables from Texas to the Southeast and can ship power the other way if demand spikes in Texas. 

Southern Spirit could better help ERCOT make it through a cold snap, avoiding some of the devastation seen during Winter Storm Uri in 2021, White House National Climate Advisor Ali Zaidi said. 

“This buildout is really transformational in breaking down the barrier between ERCOT and the rest of the country, and it feeds into this broader insight that this administration has pushed, which is essentially [that] interregional transmission translates to lower costs for consumers and higher reliability across the system,” Zaidi said. 

Southern Spirit has been under development for years, with FERC finding in 2014 that it would not trigger federal regulation over ERCOT, according to a fact sheet from Pattern. 

Phase 2 of Grid United and Black Forest Partners’ joint Southline Transmission Project would add a 108-mile, 345-kV line capable of delivering 1,000 MW of capacity across New Mexico, helping to support electricity delivery in the Southwest. It is up for $352 million. Southline Phase 1 was in the first set of projects announced last year. 

“You need only to look at the recent devastation of Hurricane Helene to know how the climate crisis is already straining our existing grid infrastructure at the precise moment when we need that infrastructure to be larger, stronger and more reliable,” White House Senior Advisor John Podesta said.

National Transmission Planning Study

The National Transmission Planning Study features a set of long-term planning tools and analyses that examine potential scenarios through 2050, including various interregional transmission expansions. 

It shows the highest level of grid reliability can be maintained at the lowest cost by coordinating interregional transmission. The study was developed by the DOE Grid Deployment Office alongside the National Renewable Energy Laboratory and the Pacific Northwest National Laboratory, who said they want other planners to use it in their efforts. 

A substantial expansion of the transmission system throughout the entire contiguous U.S. delivers the largest benefits of up to $270 billion to $490 billion through 2050. Every dollar invested in transmission leads to returns of $1.60 to $1.80 in system costs saved, the study found. 

Being able to coordinate resource adequacy across better connected regions lowers systems costs by $170 billion to $380 billion, the study found. 

The use of HVDC transmission technologies with multiple terminals — meaning power can be sent bidirectionally and from multiple entry and exit points in regions — was shown to be the most cost-beneficial way to stitch together a macrogrid across the Lower 48. 

“When translating zonal scenarios to nodal network models, HVDC was found useful for transferring power over long distances and between interconnections, but AC network expansion will continue to be the best solution for a large portion of transmission additions,” the study said. “Large interregional HVDC network solutions will also require additional strengthening of the regional AC networks they interconnect.” 

DOE has been working on the NTP since 2022. Its goal was to identify pathways that maintain current levels of reliability and saving costs while meeting local, regional and national interests, Grid Deployment Office Director Maria Robinson said on a call with reporters. 

“This study goes down to the nodal level, instead of at the zonal/regional level, and that means that this is a tool that utilities can actually use to help them determine what kinds of investments that they might want to make,” Robinson said. 

So far, interregional transmission plans have been limited, with Robinson pointing to MISO and SPP’s Targeted Interconnection Queue Study as a rare example of it actually happening. 

“So, this is why we think it’s important to make sure that these tools are available, so that it is easier for those folks who are looking to do so, and also so that we’re able to use the best-in-class modeling available from the National Laboratories,” she added. 

DOE is not going to tell FERC how to do its job, she added. Chair Willie Phillips has said the commission could look at interregional planning in the future, noting that NERC’s interregional transfer capability is due at the end of the year. (See Webinar Examines How FERC Could Use Interregional Transmission Study.) 

The department has provided some technical assistance to NERC on its interregional transfer capability study and offered updates on what was being developed in the NTP, Robinson said. 

“Of course, while doing coordination, it doesn’t mean that the exact thing will happen in both places,” Robinson said. “So, we are really looking forward, as everyone else is, to seeing the ultimate results come out of that study. But a lot of the fundamentals are relatively similar, and it’s just nice to see this greater interest in interregional transfer capacity, understanding that it can be so important in times like right now in extreme weather events.”