Large-scale regional transmission plays a key role in ensuring low costs for consumers and electric system reliability, resilience, and decarbonisation. However, investment has lagged in recent years for high-capacity, long-distance lines in all regions of the US. Recently, Midcontinent Independent System Operator (MISO) has developed a long-range transmission planning (LRTP) for a set of 18 transmission lines known as Tranche-1 in its region that would enable around 56 GW of new renewables.

When MISO assessed the benefits of Tranche-1 of its LRTP, the grid operator used six benefit metrics, including congestion and fuel cost savings, avoided cost of local generation projects and decarbonisation. With the help of stakeholders, MISO created support for a set of identified benefits and methods delivered from a portfolio worth about USD37.3 billion and a 20-year total revenue requirement of USD14.1 billion.

The American Council on Renewable Energy (ACORE) has published a report on ‘Enabling Low-Cost Clean Energy and Reliable Service Through Better Transmission Benefits Analysis’. It examines MISO’s USD10.3 billion LRTP procedure and the methods used to evaluate transmission benefits. It also compares the benefits MISO used with those suggested in the Federal Energy Regulatory Commission’s (FERC) Notice of Proposed Rulemaking (NOPR) on transmission planning. While FERC has jurisdiction over transmission planning and cost allocation, it has no standards in place on the types of benefits of or how to measure them to date.

The report suggests that FERC and other planning entities could follow MISO’s approach for benefits estimation, along with the potential improvements, in their work on transmission planning.

The report can be accessed here.