U.S. utilities and grid operators are failing to take full advantage of transmission interconnections between regions, leading to higher electricity costs and potentially reduced grid reliability, according to researchers from the National Renewable Energy Laboratory.
Developing a framework for sharing resources between grid operators is one solution for making existing interregional transmission more effective, they said in a report, Barriers and Opportunities To Realize the System Value of Interregional Transmission, released Tuesday.
Long-term, “transformative” options for improving interregional transmission include conducting nationwide interregional transmission planning and creating a national grid operator to oversee network planning, scheduling and resource adequacy, according to the report.
“As we build up our interregional transmission systems, we need to take a fresh look at improving the efficiency and efficacy of the existing system, which could increase grid reliability while reducing cost,” Christina Simeone, a grid researcher at NREL and the report’s lead author, said in a press release.
While the report focuses on the existing transmission system, it has implications for transmission investments, the researchers said.
Among the barriers to fully using interconnections between grid operators, U.S. transmission owners and operators have limited operational awareness to anticipate when large power transfers are needed, according to the report. Also, in-region transmission planning may not consider projects that would be needed to accommodate increased imports and exports with neighboring regions, the researchers said.
In a sign of inefficiencies between markets, there were uneconomic power flows — higher cost power flowing into areas with lower cost electricity — between the PJM Interconnection and the Midcontinent Independent System Operator nearly half the time in 2022, according to the report.
Most market-to-market issues relate to inefficiencies in joint operating agreements between market operators, the researchers said. For example, inaccurate price forecasts and high transaction fees limit the efficient use of transmission capacity through coordinated transaction scheduling, they said.
In addition, grid operators are generally failing to take advantage of capacity on merchant high-voltage, direct current transmission lines between regions, according to the report. The California Independent System Operator’s subscriber participating transmission owner model for interstate lines could be considered by other regions, the researchers said. Under the model, CAISO can use unscheduled capacity on the lines.
NREL’s report is part of the Department of Energy’s National Transmission Planning Study, which DOE expects to release this summer. The study aims to identify transmission that will provide broad-scale benefits to electric customers, according to DOE.
