Unlocking the Grid

When a new power plant wants to connect to PJM, it must undergo a series of “interconnection studies,” where PJM and the transmission owner analyze the impact of the new power plant on the entire PJM grid. New power plants are required to pay for any required “network upgrades” to PJM’s system that are needed to support them, including new transmission lines, substations, and updates to existing infrastructure. In some areas, new power plants can take advantage of existing “space” on the transmission system and might not need network upgrades—but NRDC’s analysis found that this is rarely the case. The power grid is full. 

Network upgrades can be expensive. The average cost of the necessary network upgrades identified in NRDC’s analysis was $28 million. These costs are on the rise nationwide, according to the Lawrence Berkeley National Laboratory. Power plant developers also don’t know these costs up front and may only learn the true cost of their project years down the road. When network upgrades are too expensive, power plant developers withdraw from the interconnection process, and their projects never get built. NRDC analysis found that multiple projects withdrew in the same area, year after year, due to the same network upgrades. When network upgrades are needed in the same location year after year, this indicates areas where the grid is overburdened and outdated, leaving valuable new power unbuilt. 

Network upgrades can also take a long time to construct. Most new power plant projects that NRDC analyzed were stuck behind more than three-year transmission construction timelines, even after clearing the interconnection queue. This is a national trend: Upgrade timelines have increased from an average of 19 months in 2015 to 35 months for those built in 2024, according to the Lawrence Berkeley National Laboratory. Many power plants themselves, including high-capacity battery storage, can be built within 18 months, but almost all projects that can afford network upgrades are trapped behind multiyear delays.  

NRDC looked through PJM’s historic interconnection queues to find common network upgrades that emerged in multiple queue cycles, repeatedly associated with withdrawn power plants. These upgrades are a clear indication of where the grid is overburdened and repeatedly blocking new energy. 

Since 2018, there have been 59 network upgrades identified in PJM’s interconnection studies associated with repeated project withdrawals. The two states with the most identified network upgrades are Virginia (Dominion Energy) and Illinois (ComEd) (Figure 1).

These network upgrades have affected approximately 26 GW (total capability or nameplate) of new power plants from 206 projects representing a variety of sources, including onshore and offshore wind, solar, and storage. Figure 2a and 2b show the total requested capability (nameplate) and capacity of resources that withdrew from the interconnection queue between 2018 and 2025 by state.

In December 2025, PJM completed its latest interconnection study (Transition Cycle 1). This should have been a moment to celebrate, but instead, developers found out they were trapped behind multiyear delays. In total, 94 percent of new power plants that completed the latest queue cycle will face network upgrade timelines of three years or more, representing 98 percent of the total capacity. Almost all this capacity will not be able to connect to the grid until 2029 or later, despite the ability for power plants and battery storage resources to be constructed years earlier (Figure 3). Many of these resources, such as offshore wind generation, require multiple network upgrades to interconnect to the grid, adding complications and delays.

This analysis shows that PJM’s outdated grid is preventing and delaying gigawatts of new power from connecting. Ultimately, there are two solutions: build the necessary network upgrades or find ways to get around them. NRDC’s fact sheets outline ways that states can build upgrades, scrutinize delays, and encourage new power plant development in areas that won’t be hampered by these bottlenecks.  

• To reduce delays, states can work with utilities to understand why delays are occurring and how to overcome them through regulatory hearings and new rulemakings, holding transmission owners accountable to ambitious but realistic timelines.
• To build upgrades that will unlock gigawatts of new clean energy, states can plan and pursue innovative funding mechanisms. The high costs of network upgrades may be a barrier for new power plant developers, even if the power plants are necessary to meet emerging load growth or meet state policy goals. States may be able to fund network upgrades, including in partnership with neighboring states, and recover revenues from power plants once connected. Additionally, states can encourage PJM to include repeating network upgrades in its regional planning, which was required under the 2024 Federal Energy Regulatory Commission (FERC) Order 1920.
• To get around network upgrades, states can encourage PJM to evaluate whether network upgrade needs can be mitigated with alternative transmission technologies, like dynamic line ratings, advanced conductors, and power flow controls, which are faster and cheaper than many traditional network upgrades. States can also incentivize new power plants to use Surplus Interconnection Service, or replace retiring units at the same location, bypassing network upgrades entirely by using existing system headroom and infrastructure.

PJM must recognize that network upgrade delays and withdrawals are not going away. To maintain reliability, meet skyrocketing demand, and lower consumer costs, PJM must pursue deeper paradigm shifts. PJM could learn from neighboring Southwest Power Pool  and harmonize interconnection and transmission planning or seek inspiration from the Electric Reliability Council of Texas  to allow new power plants to connect as soon as possible but be subject to curtailment if transmission hasn’t been built to support them yet.  

Residents, businesses, and families in PJM cannot afford to ignore these significant blockers of new, affordable clean energy that will lower prices and keep the lights on. Instead, states and PJM must work together to clear the logjam—for good.