The transmission organization that operates the United States’ largest multi-state grid has greenlighted a US$10.3-billion investment in high-voltage transmission lines to clear bottlenecks that have impeded nearly 100 gigawatts of new solar and wind capacity.
The 18 transmission projects approved by the Midcontinent Independent System Operator (MISO) last July “are designed to facilitate an expected shift in MISO’s generation mix, including the retirement of about 58 gigawatts of mainly coal-fired power plants, and the addition of about 90 gigawatts of solar, gas and wind by 2039,” reports Utility Dive, citing Aubrey Johnson, MISO’s vice president of system planning and competitive transmission.
MISO operates across 15 U.S. states and the Canadian province of Manitoba to deliver electricity to 42 million consumers. It has the largest geographic footprint of any independent system operator in the U.S. and manages roughly 104,000 kilometres of high-voltage transmission and 200,000 megawatts of generation resources from a mix of coal, natural gas, nuclear, wind, and solar energy.
Like other stakeholders in the electric industry, MISO has had growing concerns about transmission infrastructure as it prepares for changes in energy policy and an increase in severe weather threats, both linked to climate change. The organization undertook a long-range transmission planning process, recognizing that the region’s shift from coal and natural gas to wind and solar had created “real issues with the transmission system being able to accommodate it,” Sam Gomberg, transmission policy manager with the Union of Concerned Scientists’ climate and energy program, told Canary Media in April.
The recent investment decision aims to address transmission issues and overcome the infrastructure limitations to accommodating new renewable energy generation. The transmission projects are expected to come online in 2028 and boost MISO’s ability to add 53 gigawatts of renewable energy to the grid, while making up for 50 gigawatts of aging coal-fired power plants that are scheduled to be shut down, says the Institute for Energy Economics and Financial Analysis.
“The generational resource fleet is undergoing broad and rapid changes. At the same time, we’re seeing increased frequency of extreme weather events,” Johnson told a MISO board meeting. “Those, along with other factors, create the need for new backbone transmission infrastructure.”
To inform the decision, MISO conducted a cost-benefit analysis covering a broad range of measures. It showed that the new transmission plan would produce benefits valued at $37.3 billion, 2.2 times the initial investment. Afterwards, the American Council on Renewable Energy (ACORE) said MISO’s comprehensive analysis should be used as a framework for a national approach to measuring transmission benefits, Utility Dive reports.
“When the benefits of proposed transmission lines are fully calculated, the advantages of new lines are made clear to regional planners,” ACORE President and CEO Greg Wetstone, ACORE said in a statement. “Building off MISO’s forward-leaning process, our analysis offers a roadmap for [the U.S. Federal Energy Regulatory Commission] and other planning entities that, if adopted, will result in a cleaner, lower-cost electric grid.”