New Report: U.S. Lagging on HVDC Transmission Deployment

U.S. grid operators lag far behind international counterparts in deploying a technology that is supporting grid modernization efforts across the world, according to a new report from The Brattle Group and DNV. High-voltage direct current (HVDC) transmission technology is expanding rapidly, with more than 300 gigawatts (GW) of installed capacity worldwide and 150 GW planned over the next decade.

The report, “The Operational and Market Benefits of HVDC to System Operators,” offers nine recommendations to address barriers the technology faces in the U.S. The report is sponsored by the American Council on Renewable Energy (ACORE), Allete, Clean Grid Alliance, GridLab, Grid United, and Pattern Energy Group.

“HVDC technologies offer a tremendous opportunity for the U.S. to upgrade and expand its aging transmission system, but we need to act now to address obstacles preventing greater domestic deployment,” said Johannes Pfeifenberger, Principal with The Brattle Group and report co-author. “HVDC technology offers capabilities that are uniquely well suited to address growing grid needs, but planning and developing valuable HVDC solutions will require close collaboration between grid operators and various stakeholders, including industry groups, regulators, manufacturers, and the federal government.”

European grid operators have led the way in deploying modern HVDC technology based on voltage source converters (VSC) in recent years, with about 50 GW of projects operating and another 130 GW planned over the next 10 years. North America accounts for only 3 percent of all VSC-based HVDC systems in operation worldwide and, mostly due to efforts by merchant transmission developers, for approximately 30 percent of planned and proposed VSC systems.

Among various recommendations, the report suggests that U.S. system operators work with the North American Electric Reliability Corporation (NERC) to develop technical guidelines that not only accommodate HVDC transmission but also allow grid operators to take full advantage of VSC-based capabilities. Technical experts, National Labs, manufacturers, and other stakeholders must also work together to share HVDC expertise and provide training for planning, engineering, and operations staff.

Importantly, international demand for these technologies has resulted in years-long lead times for purchases, threatening near-term deployment on the U.S. grid despite the need for system upgrades.

“The lack of up-to-date, complete, and consistent planning guidelines for HVDC transmission systems is stymieing U.S. growth of this critical grid equipment and the creation of a local supply chain,” said Cornelis Plet, co-author of the report and Vice President of Power System Advisory at DNV. “European grid operators, in collaboration with government, have driven significant demand through pre-orders and long-term commitments. The U.S. must build a similar project pipeline and, importantly, take advantage of the significant planning and operational experience that has already been gained with modern HVDC systems.”

HVDC technologies are cost-effective solutions for high-capacity, long-distance transmission that can offer advantages compared to conventional, high-voltage alternating current (AC), including reducing AC grid congestion, supporting weak AC grids, and improving grid stability.

“As an independent transmission developer, we view HVDC technologies as a no-brainer for meeting increased power demand, ensuring reliable electricity, and reducing costs for consumers,” said Michael Skelly, CEO of Grid United. “HVDC technology helps the AC grid run more efficiently, improving resilience. This report offers a blueprint to alleviating obstacles to bring these technologies online.”

Addressing the challenges to HVDC deployment will require proactive grid planning processes that take advantage of the technology’s attractive capabilities.

“Increased HVDC deployment will help bolster the aging U.S. power grid to better meet America’s changing power needs, particularly as we transition to cleaner electricity sources,” said ACORE President and CEO Gregory Wetstone. “Industry, reliability experts, and government officials must work together to quickly implement these recommendations and start taking advantage of the flexibility and grid stability benefits this technology provides.”

Additional comments from report sponsors:

“The U.S. must take note of the useful examples in this report that detail how other nations are leveraging HVDC transmission technologies to modernize their grids and deliver more reliable, lower-cost power,” said Hunter Armistead, CEO of Pattern Energy. “It’s time for America to capitalize on this flexible grid technology, like we are doing with our SunZia transmission line, and meet the country’s 21st century electricity needs.”

“HVDC technologies enable grid planners to make targeted system reinforcements, avoiding some of the issues that plague AC grids and require multiple system upgrades,” said Ric O’Connell, Executive Director of GridLab. “HVDC offers a significant transmission planning benefit that will truly benefit grid operators facing reliability challenges while also seeking to add new resources to their systems.”

"MISO is considering deploying HVDC technologies as part of the Tranche 2 projects in its long-range transmission plan, but there is a lot of modeling and analysis yet to be done in the work MISO is doing to arrive at a Tranche 2 portfolio of lines. CGA wants the MISO transmission planning process to fully consider the benefits HVDC technology offers to address system stability challenges with increased renewable penetration,” said Beth Soholt, Executive Director of Clean Grid Alliance. “This report offers concrete steps the grid operator can take to ensure these technologies are part of future transmission plans, improving reliability across Midwestern states.”

“The benefits of greater interregional transmission capacity across the nation are growing, particularly during extreme heat and cold weather events,” said Julie Pierce, Vice President Strategy and Planning from ALLETE, Inc. “This report offers concrete actions the U.S. can take to prepare to efficiently integrate HVDC transmission to ensure consumers have access to reliable and life-saving power.”