The United States’ power grid is facing a new era of electricity demand growth as data centers come online and factories, electric vehicles, and buildings switch to affordable electric technologies.
But we’re still stuck in yesterday’s approach to connecting new electricity generation resources to our power grid. On average, a power plant that wants to connect to the grid must wait five years or more before it can supply power. With aging coal plants retiring while data centers and electric vehicles seek new power supplies, this wait time is simply too slow. Using existing connection points can bring projects online in two or three years compared to an average of five for the standard process.
Meanwhile, electricity prices have soared 13 percent since January 2025, and a big portion of that increase is the price of building new poles and wires even though electricity generation costs are falling.
Fortunately, an innovative policy shortcut can speed up the time to connect to the grid and help reduce the amount of new infrastructure we need to build – surplus interconnection. The potential is massive – Researchers from UC Berkley estimate that over 1,000 gigawatts of new wind and solar and 260 gigawatts of energy storage[1] could be added to the grid.
America’s electricity system currently has about 1,300 gigawatts (GW) of power capacity installed across thousands of power plants, but we have over 2,200 additional GW just waiting in line to connect.[2] While likely not all of these projects are viable, it demonstrates the massive barrier that interconnection has come to represent. These projects are typically delayed by studies that determine exactly how they need to be connected, as well as by the process of building that infrastructure.
The key to surplus interconnection is that many existing fossil fuel power plants aren’t running or using the grid infrastructure allocated to them all of the time. Because these power plants and transmission lines aren’t being used 100 percent of the time (generators on average are only in use 50% of the time),[3] this “surplus” space on the power grid means we can add more new electricity generation right where these existing power plants are by sharing a grid connecting with existing infrastructure, plugging into the grid without having to build any new lines or towers.
Think about it like this: Railroad tracks are only used 10-30 percent of the time, and hit their highest use during rush hour. But the tracks are available 100 percent of the time, just waiting around ready to be used. What if trains used this time to transport other goods, getting things where they need to go without needing to build any additional tracks?
The best candidates for sharing a grid connection using surplus interconnection include peaking gas power plants that only turn on during the times of highest electricity demand, wind plants that mostly generate at night, or any solar plant that can combine with battery storage to soak up cheap power during the day and discharge at night during the evening air conditioning peak. This helps cut costs for families and businesses because it uses existing poles and wires for a larger percentage of the time, which means that the fixed costs of the grid can stay lower.
These existing connections to the grid have already been studied and approved by grid operators, and in most cases, making better use of these connections should avoid costly grid upgrades that can drive up the price of new power projects. For example, in 2017 a solar project in Kansas that was trying to connect to the grid via the typical interconnection process that involved building new power lines, facing costs of over $300/kW for these upgrades and an expected completion date in 2025. Four years later, a similar solar project in the neighboring county requested to connect via surplus interconnection in 2021 – interconnection costs this time were less than $1/kW, and completion date was only two years later in 2023.[4]
Surplus interconnection goes into action in Utah
In Utah, an 80 megawatt (MW) solar facility in Emery County[5] added battery storage, enabling the power plant to store electricity during the day and export it to the grid during peak evening hours. Typically, this would require new interconnection studies and upgrades to allow the solar and batteries to inject power into the grid simultaneously, requiring wires double the size.
However, because the batteries would be operated in the evening when the solar project was not generating electricity, the two projects could simply use the existing 80 MW connection and output power to the grid at different times, turning the facility into a reliability powerhouse without paying or waiting for any upgrades to the grid.
Now, PacifiCorp is planning for a similar arrangement at four more sites across the state,[6] aiming to add an additional 320 MW of storage with no grid upgrades. The agreement is simple – the operator can use the solar and batteries as they see fit, as long as the overall grid output does not exceed the 80 MW maximum.
Surplus interconnection is gaining traction across the country. In 2026, Indiana and Virgina passed legislation to promote surplus interconnection.[7] In Virginia, two utilities will now be required to evaluate how much surplus interconnection capacity is available at existing and planned renewable sites. In Indiana, utilities are now required to analyze and include surplus interconnection’s potential to meet grid needs as a part of utility planning processes.
Generator replacement goes a step beyond surplus in Minnesota
Surplus interconnection can add new generation at existing power plants, but the same concept can also be applied to dozens of large old power plants across America that are planning to retire in the next five years, leaving their connections to the grid open to replacement resources.
In Minnesota, one local utility is using the interconnection capacity left behind by the retirement of the Sherco coal plant to add over 900 MW of solar alongside 600 MW of energy storage[8], and is connecting to the grid using the poles and wires left behind by the of the retiring 2,200 MW coal plant. The new Sherco Energy Hub will be able to tap federal tax credits before they are repealed by the One Big Beautiful Bill Act because the speed of the generator replacement process will allow the utility, Xcel Energy, to break ground by the 2026 July deadline.
The surplus opportunity could meet the needs of today
With surplus interconnection and generator replacement available as proven strategies to bring needed power online quickly, America can accelerate the way projects connect to the grid––reducing costs for developers, and ultimately all electricity customers. could be added to the grid. Now is the time to take advantage.
[1] Umed Paliwal, Emilia Chjkiewicz, Nikit Abhyankar, Amol Phadke, “Existing plants sharing grid access with renewables can lower costs and double U.S. generation capacity,” GridLab, UC Berkeley, (2025): https://gridlab.org/portfolio-item/surplus-interconnection-technical-report/
[2] Joseph Rand et al, “Queued Up: 2025 Edition,” Lawrence Berkeley National Laboratory, (2025): https://emp.lbl.gov/sites/default/files/2025-12/Queued%20Up%202025%20Edition%20-%2012.15.2025.pdf
[3] Ryan Hledik, Long Lam, Kate Peters, “The Untapped Grid: How Better Utilization of the Power System Can Improve Energy Affordability,” The Brattle Group, (2026): https://www.brattle.com/wp-content/uploads/2026/03/The-Untapped-Grid-Mar-2026.pdf
[4] Chelsea Mattioda, Sarah Shenstone-Harris, Sophie Schadler, Jack Smith, “No-Regrets Solutions for Accelerating Grid Interconnection,” Synapse Energy Economics, Inc., (2024): https://www.synapse-energy.com/sites/default/files/No-Regrets%20Solutions%20for%20Accelerating%20Grid%20Interconnection_Final%20Synapse%20Report%208.19.24%2023-132.pdf.
[5]Robert Eckenrod, “RE: PacifiCorp, Docket No. ER25-____-000 Surplus Large Generator Interconnection Agreement and Energy Displacement Agreement”, PacifiCorp, (2025): https://pscdocs.utah.gov/misc/25docs/2599901/340389RMPSrplsLrgGnrtrIntrcnctnAgrmntEnrgyDsplcmntAgrmntFERCER2526296-26-2025.pdf?
[6] “Utah 2025 Integrated Resource Plan”, PacifiCorp, (2025): https://pscdocs.utah.gov/electric/25docs/2503522/339034RMP2025IRPVlmI3-31-2025
[7] Ethan Howland, “Virginia, Indiana lawmakers pass surplus interconnection bills,” Utility Dive, (2026): https://www.utilitydive.com/news/virginia-indiana-surplus-interconnection-pjm-miso-spp/813442/
[8] Brian Martucci, “Xcel doubles down on plan to swap coal for clean power in Minnesota,” Canary Media, (2025): https://www.canarymedia.com/articles/energy-storage/xcel-minnesota-increase-battery-solar-sherco
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