Even through a challenging economy, renewable energy generation has continued to gain ground in the last several years. In its February forecast, the U.S. Energy Information Administration estimated solar and wind projects will make up 65% of all new capacity added in 2023. However, supply chain and permitting issues have hindered what could be even faster adoption of these carbon-free resources.

Boosting cross-country transmission capacity could help speed uptake by allowing renewably generated electricity to be used farther from its source. This could help boost generators’ profitability by enabling new markets during peak periods when production might be curtailed due to limited local demand. 

Improving overall system efficiency in this way could mean less overall infrastructure and monthly utility bill savings. These goals are behind one company’s plans to ship power across currently constrained regional divisions by way of five ambitious new transmission projects now on the drawing board.

Houston-based Grid United came together in the aftermath of February 2021’s winter storm Uri, which left millions without electricity for days in frigid temperatures. While transmission systems held up, generation did not, and because Texas operates its own, largely closed electrical system, utilities couldn’t call on supplies outside state lines for support.

The trifurcated transmission system

This event provides an extreme example of challenges posed by the country’s trifurcated transmission system, now divided between the Eastern Interconnection, Western Interconnection and the Electric Reliability Council of Texas (ERCOT). Only about 1,300 megawatts of transfer capacity exist between the Eastern and Western interconnections—roughly the capacity of a couple natural gas combined-cycle generators. Even less power can be transferred across ERCOT’s borders. With more open power flow, it’s possible Texas utilities could have avoided the rolling blackouts during 2021.

But it’s not just Texas that would benefit from more robust links between the nation’s three interconnections. A 2020 National Renewable Energy Laboratory study found that with increased intercontinental transmission, the nation’s grid would be able to balance generation and load with fewer resources in each respective region—it could do more with less. Researchers showed that such investments could reap benefits for utility customers of up to almost triple their costs.

New HVDC lines

This is the opportunity Grid United is promoting in its plans for five new high-voltage direct current (HVDC) transmission lines that would establish new links across regional borders. Company founder and CEO Michael Skelly is something of a veteran with this technology, having previously led Clean Line Energy Partners, a transmission developer that tried—and failed—to get the approvals needed for several HVDC lines designed to bring Great Plains wind energy to eastern states. One of those projects, the $7 billion Grain Belt Express, now owned by Chicago­-based Invenergy, recently gained new life in its efforts to connect Kansas wind to markets in Missouri, Illinois and Indiana, when Missouri legislators finally signed off on the deal in May 2022.

The five HVDC routes Grid United is proposing are less complicated than those Clean Line had designed, with two remaining within a single state’s borders and the other three only crossing one state line each. This should make negotiations easier, since transmission lines, like utilities, are regulated at the state level. And because HVDC lines can carry power in either direction, those lines that do cross two states could be seen as providing benefits to both. The full lineup includes:

• North Plains Connector, which will travel approximately 385 miles through Montana and North Dakota to bridge the Eastern and Western interconnections.
• Pecos West Intertie, which aims to tie the non-ERCOT corner of Texas that’s home to El Paso to the rest of the state’s grid. This 285-mile line could help keep lights on in the state during future severe weather events. However, it will not be a synchronous connection because an intermediate converter station is required to transition the line’s HVDC power to ERCOT’s AC standard. Developers believe this will allow the state to maintain regulatory independence from federal regulators.
• Southline Transmission Project, a 280-mile line that would connect the Tucson, Ariz., and El Paso, Texas, metropolitan areas, running through Arizona and New Mexico. Presumably, this could also help support the Pecos West line’s operations.
• Three Corners Connector, which would run up to 300 miles between Pueblo, Colo., and the Oklahoma Panhandle, connecting the Eastern and Western interconnections.
• Wyoming Intertie, which would bridge the interconnection gap within Wyoming’s borders. It would run 100 miles between two existing substations in Medicine Bow and Wheatland.

All projects are currently in the planning and development phases. The Southline effort is farthest along in the approval process—construction on that line could begin in 2024, according to the project’s website. Current schedules have all the lines operational by 2029, but that could be an optimistic prediction given the need for new rights-of-way and politics.