DOE backs Texas-to-US grid connection project with $360m

Southern Spirit, a project in the US aiming to connect the Electric Reliability Council of Texas (ERCOT) grid with southeastern US grids, has received approximately $360 million support in a contract from the US Department of Energy (DOE).

Pattern Energy’s Southern Spirit would build an approximately 320-mile ±525kV, 3,000MW HVDC transmission line, connecting ERCOT with electric grids in the southeastern US power markets, including Midcontinent Independent System Operator South (MISO-S) and Southern Company (SOCO).

By connecting the Lone Star State’s grid with MISO-S and SOCO, the project aims to enhance reliability and prevent outages during extreme weather events, such as Winter Storm Uri that hit Texas in 2021.

The storm battered the Texas grid, resulting in the largest controlled load shed in US history at an estimated peak of 20GW and a total of 1,016GWh.

According to the National Renewable Energy Laboratory, at the time, more than 4.5 million people in Texas lost power for as long as four days.

A project such as Southern Spirit would provide support during extreme weather events by allowing power to be shared between grids, while preserving ERCOT’s independence via granted Federal approval, says Pattern Energy.

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Part of a $1.5bn DOE investment

The DOE’s support for the project forms part of a larger investment by the department of $1.5 billion to improve grid reliability across the country.

The investment will be doled out across four projects, including Southern Spirit, through the Transmission Facilitation Program, a revolving programme aiming to help overcome the financial hurdles facing transmission development.

The three other projects to enter capacity contract negotiations with the DOE include:

• Aroostook Renewable Project ($425 million), which will construct a new substation in Haynesville, Maine and a 111-mile transmission line with a capacity of 1,200MW to connect the new substation to the Independent System Operator-New England (ISO-NE) system at a substation in Pittsfield, Maine.
• Cimarron Link ($306 million), a 400-mile HVDC transmission line from Texas County, Oklahoma to Tulsa, Oklahoma, which will transmit 1,900MW of firm, point-to-point capacity to deliver low-cost wind and solar energy to growing load centres in eastern Oklahoma and elsewhere in the Southwest Power Pool.
• Southline ($352 million), which will construct a new 108-mile transmission line that will deliver 1,000MW of new, bidirectional capacity between Hidalgo County, New Mexico and Las Cruces, New Mexico, helping meet energy needs of industries investing in the region, including semiconductor, battery manufacturing, and data centre facilities.

Commenting in a release was US deputy secretary of energy, David Turk: “The US transmission network is the backbone of our nation’s electricity system. Though our grid has served US energy needs for more than a century, our country’s needs are changing.”

“DOE’s approach to deploying near-term solutions and developing long-term planning tools will ensure our electric grid is more interconnected and resilient than ever before, while also supporting greater electricity demand. The Biden-Harris Administration is committed to bolstering our power grid to improve the everyday life of Americans through affordable power, fewer blackouts, more reliable power, and additional jobs across our country.”

A transmission planning study

At the same time as the project announcements, the DOE also released the final National Transmission Planning (NTP) Study.

The study, a set of long-term planning tools and analyses, finds that the US will need to approximately double to triple the 2020 transmission capacity by 2050 to meet demand growth and reliability needs.

While transmission planning in the US usually happens at the local or regional level, the study shows that grid reliability can be maintained at the lowest cost with the highest level of reliability by coordinating interregional transmission.

It states that a substantial expansion of the transmission system throughout the entire contiguous US will deliver the largest benefits and could lead to national electric system cost savings of $270 billion–$490 billion through 2050. Transmission investments were also found to yield significant ROI, with every dollar spent meaning approximately $1.60 to $1.80 in system costs saved.

Additionally, it finds that when transmission regions coordinate to achieve resource adequacy, system costs through 2050 are lowered by $170 billion–$380 billion.