By Mark Jaffe, EUCI energy writer
The combination of coal-fired power plant closures, spurred by state and federal initiatives, and generous tax credits for new electric generation under the Inflation Reduction Act created a flood in renewable energy projects now waiting to get connected to the grid.
“The surge in investment and development has overwhelmed interconnection queues, with a record number of projects seeking grid connections,” according to an analysis by Enverus Energy Research. “This has exceeded grid operators’ processing capacity, causing significant delays and project suspensions.”
In 2024, projects had been in the connection queue ranging from more than nine years for the California Independent System Operator (CAISO) to just under four years for the New England Independent System Operator (ISO-NE).
Some of the largest grids, including the New York Independent System Operator (NYISO), the PJM Interconnection, which covers Midwest and mid-Atlantic states, and the Southwest Power Pool (SPP), are seeing suspension rates for projects ranging from 46% to 79%.
“Projects in these markets show minimal improvement in completion probability until reaching construction,” Enverus said.
By comparison, the suspension rates averaged 20% for the Electric Reliability Council of Texas (ERCOT), the Midcontinent System Operator (MISO) and CAISO.
Enverus said it expects only a fraction of capacity in the interconnection queues to reach operation with only about 10% of projects successfully coming online in the next three years.
In 2026, Enverus projects 525.8 gigawatts (GW) of new capacity is set to come on the grid, including 332 GW of solar, 44 GW of onshore wind, and 144 GW of battery storage.
The PJM had the most planned capacity in 2024, 92 GW, which included 86.7 GW of solar and 11 GW of battery storage.
That was followed by Texas and California. ERCOT had 36 GW of planned capacity, including 21 GW of solar and 11 GW of storage and CAISO had a total of 23 GW, including 17 GW of battery storage.
The most capacity installed in 2024, however, was in ERCOT – 14.5 GW, including 7.7 GW solar, 2.2 GW of wind, and 4.6 GW in storage.
“ERCOT saw significant growth in new capacity throughout 2024, especially from solar and energy storage projects,” Enverus said. “Planned capacity in ERCOT remains consistent from 2024 to 2025 across solar, wind, and energy storage.”
Developers have taken advantage of the Texas grid operator’s small generation queue, which offers a faster process, Enverus said. Most small generation requests are battery storage projects with a capacity of just under 10 megawatts (MW).
The average wait time in the ERCOT queue was 4.5 years. The only grid operator with a shorter queue time was ISO-NE at 3.8 years. ISO-NE also had the smallest 2024 planned capacity, 4 GW.
In NYISO, an “extreme backlog” has led to a new process aimed at expediting projects. For the 110 solar, wind, and energy storage projects in the traditional queue, current average wait time is 6.5 years.
The PJM is the country’s largest grid operator. State renewable energy targets and transition from aging coal-fired plants account for a quarter of the interconnection request on its grid, with solar the main capacity addition.
“The queue remains under significant strain with more than 300 GW of renewable and storage requests waiting to interconnect,” Enverus said.
CAISO is also “severely backlogged” with the grid operator still working through approvals for 2021 while not having approved any projects from the 2022 or 2023 connection proposals.
SPP, whose grid stretches across all or parts of 14 states from Texas to North Dakota, has a six-year project backlog. The grid operator has won approval from the Federal Energy Regulatory Commission to prioritize backlogged historical projects over 2024 generation.
“SPP is seeing surging generator interconnection requests — almost entirely from solar, wind, and battery storage,” Enverus said. The grid operator has also approved a $7.7 billion plan to strengthen its transmission network in response to increasing energy demand.
MISO, which covers all or parts of 15 states from Louisiana to Minnesota, also had a six-year backlog and in 2024, it saw a “massive shift” from wind generation to solar generation.
A little more than 4 GW of solar came online in 2024 along with 615 MW of wind. In the previous five years, there were more than 15 GW of new wind generation.
“Most reported delays are due to transmission owner supply chain or regulatory issues,” Enverus said.
MISO has approved a $22 billion portfolio of transmission projects across its Midwest subregion with 3,631 miles of lines with service dates from 2023 to 2034.
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