US needs power highways from the Plains to spread wind, solar benefits

A swathe of grid expansions are needed in Central U.S. to pursue national renewable energy goals and lower power prices in neighbouring regions, the Department of Energy said in a draft transmission study.

As the Biden administration takes measures to hike renewable energy deployment, a new national study highlights the importance of new transmission capacity in the middle of the country.

The U.S. must rapidly expand its power grid to achieve President Biden's target of a decarbonised power sector by 2035. Wind and solar deployment is set to soar on the back of tax credits in Biden's Inflation Reduction Act and a lack of grid capacity is already delaying projects and inflating costs.

The U.S. must increase transmission capacity by about 57% by 2035, to 47,300 GW-miles, based on a scenario of moderate load and high clean energy deployment on the back of the inflation act and other enacted legislation, the Department of Energy (DOE) said in a draft National Transmission Needs Study published last month.

Supported by the 2021 Bipartisan Infrastructure Law, the study will help the DOE identify high-priority National Interest Electric Transmission Corridors. The Bureau of Land Management (BLM) has authorised several GWs of new lines across federal lands under Biden’s presidency but many interstate transmission projects have been shelved in recent years following opposition from local groups and public utility commissions.

Significant transmission deployment is needed by 2030 in the Great Plains, Midwest, and Texas but the largest benefits will come from increasing interregional transmission, the DOE said in its report.

"Large amounts of low-cost generation potential exist in the middle of the country and accessing this generation through increased transmission is cost-effective for neighboring regions," the study found.

By 2035, as many as 20,000 GW-miles of new transmission could be needed in the Mountain, Plains, and Texas regions alone to support a high clean energy future, the DOE said.

"There are some connections from the middle of the country going both directions to the East and West that are very valuable, partially because we have such limited capacity between our Eastern and Western grids," said Rob Gramlich, president of advisory group Grid Strategies.

"Right in the middle of the Plain states, we have only a tiny connection between the Eastern and the Western grid, but we have a huge need and opportunity to expand that capacity."

Lower prices

Central U.S. hosts most of the nation's renewable energy potential and the DOE's study suggests increasing transfer capacity between the Plains and its neighbors on all sides. Power congestion due to high wind generation and transmission constraints have opened up price spreads between regions.

"Real-time, hourly price differences between Plains and its neighbors have been high and increasing for the past five years, indicating large value in increased transmission between the regions," it said.

         Average difference between zonal power prices in H1 2022

                                                            (Click image to enlarge)

Source: Lawrence Berkeley National Laboratory

An average of 21.1 GW of new transfer capacity is needed between the Plains and the Midwest by 2035, up 175% from 2020, according to the study.

A further 19.7 GW of capacity is required between the Plains and Delta regions, an increase of 414% on 2020 levels, it said.

Transfer capacity with Texas must rise 13-fold to 9.8 GW, based on moderate load and high clean energy scenario, and expansions are also required between the Plains and Mountains and between the Plains and Southwest regions, it said.

Relieving congestion points in the Plains, Midwest and Delta regions allows different renewable resources to offset each other and provide the geographic diversity that supports a reliable grid, said Christina Hayes, executive director of Americans for a Clean Energy Grid (ACEG).

"Some of the congestion is attributable to renewable resources," Hayes said. "There is a tonne of wind in the Plains and MISO North, and sometimes it is that wind in the classic Midwest area that needs to make its way to the Delta, where it is needed, where it could be offset by solar."

Grid solutions

The DOE study forms part of the Biden administration's Building a Better Grid initiative that will oversee $2.5 billion of funding towards development of nationally significant transmission lines, $10.5 billion towards grid resilience, $760 million of grants to grid siting authorities for interstate high-voltage lines, along with funding to protect grid infrastructure from extreme weather events.

The report is open for public consultation until April 20 and in the winter of 2023 the DOE will publish a long-term National Transmission Planning Study and a portfolio of potential transmission solutions that will enable a national transition to clean energy.

The transmission needs study could help the U.S. move towards a minimum requirement for interregional transmission in future expansion plans, said Johannes Pfeifenberger, economist and expert on Electricity Wholesale Markets & Planning at consultancy Brattle Group.

"Market participants have been contemplating whether there should be a minimum requirement for interregional transmission from a resilience and market efficiency perspective," Pfeifenberger said. "It may be possible to take at least the low end of the DOE summary results and say, let's build at least that much."

Reporting by Anna Flavia Rochas

Editing by Robin Sayles