The Midwest Is Throwing Away Wind Because It Cannot Move It. That Is a Transmission Bill, Not a Wind Problem

In 2023, grid operators in the Southwest Power Pool and the Midcontinent Independent System Operator curtailed an hourly average of 800 megawatts of wind generation, compared with less than 200 MW in 2019. Curtailment means a wind farm that could have generated was told not to. The energy was available, the turbines were spinning or could have been, and the system did not take it. Wind made up 36% of SPP's total generation in 2023 and 15% of MISO's.

In practice, congestion is the larger part of the story in both markets. Wind farms are concentrated in the western parts of SPP and MISO, where land is cheap and wind is strong. MISO congestion often occurs during winter storms, when high winds coincide with transmission constraints. The EIA notes that curtailments in winter 2023 to 2024 were lower than in the two previous winters, partly because of better resource planning and congestion management during storms.

Coal-fired plants in PJM ran at just 34% of capacity in 2023, compared with 56% in 2013. The comparison matters because it shows two very different reasons that capacity can sit idle. PJM's coal fleet runs less because it is expensive relative to alternatives. One response to curtailment is to store the energy locally and release it later, when lines have room. Utility battery data from the EIA show this is the most common use case for US storage.

In a congested wind region, arbitrage effectively means charging when local prices collapse because of excess wind, and discharging when the congestion clears. High-voltage lines across multiple states take a decade or more to plan, permit and build. The Federal Energy Regulatory Commission's Order No. 1920 on long-term regional transmission planning, issued in May 2024, requires regions to plan over a longer horizon and to consider a wider range of benefits.