Renewable energy is on the rise. At the same time, severe weather events are increasing in frequency. Combined, these two trends are putting added pressure on transmission infrastructure, and providers are making major investments in upgrades to meet the challenge.

In the northern states, the Midcontinent Independent System Operator (MISO) is proposing a set of transmission line projects with a huge price tag, but the benefits are expected to be even bigger.

At a March 29 workshop, MISO outlined the business case for its proposed Long Range Transmission Planning (LRTP) Tranche 1 Portfolio. The portfolio includes 14 transmission projects in seven different locations, with a total price tag of about $10.4 billion. The transmission lines would support a variety of needs in the service area, including transmission of renewables, congestion relief, improved connectivity and reducing the risk of load shedding due to severe weather events.

The lines will benefit transmission in areas of several states serviced by MISO, including North and South Dakota, Iowa, Indiana, Illinois, Minnesota, Wisconsin, Michigan and Missouri.

While the price tag is big, the benefits are expected to be far greater. MISO says its analysis indicates the total benefit will “significantly exceed” the cost of the portfolio. Over a 20-year horizon, total benefits are expected to reach $36 billion. That number reaches nearly $70 billion on a 40-year horizon. Adjusted for inflation, the proposals provide a total 20-year “present value benefit to cost ratio” of 2.6.

These numbers reflect a multitude of benefits, including congestion and fuel savings, avoided capital costs, avoided transmission investment and decarbonization.

The portfolio will potentially use up to 750 miles of existing rights-of-way to offset the cost of replacing aging equipment and structures. The proposal will undergo additional review, with final approval scheduled for July 2022.