Interconnection queue
Also known as: grid interconnection queue, generator interconnection queue, grid connection queue
An interconnection queue is the line of proposed power plants and battery projects waiting for permission to connect to the electricity grid.
Before connecting, each project must be studied to see whether the grid can handle it and what upgrades are needed. While it sounds like paperwork, the queue has become one of the biggest bottlenecks in the energy transition: far more capacity is waiting to connect than is actually running in many regions.
Interconnection queue, explained at three levels
At home
Imagine a busy highway on-ramp with a long line of cars waiting to merge. Each new power project is a car, and the grid operator has to check that the highway has room before letting it on. That waiting line is the interconnection queue.
At work
Developers must enter the queue before building a power project. Long waits and uncertain upgrade costs can make projects miss financing windows, raising costs or killing them entirely.
At home
Each project goes through studies of how it would affect power flows and stability. If the grid needs upgrades, like a new substation, the developer may have to pay for them. Many projects drop out when they see the bill.
At work
Queue reforms include cluster studies that evaluate many projects together, higher deposits and site-control requirements to deter speculative applications, and 'first-ready, first-served' approaches. Some regions allow surplus interconnection, adding batteries at existing sites, or faster processes for projects that replace retiring plants.
At home
Most of the capacity in the queue will never be built, which makes the queue a bad measure of what's coming. In my opinion, completion rates and average wait times tell you far more about a region's energy future than the headline gigawatts.
At work
Upgrade cost allocation is the central economic issue: assigning large network upgrades to whichever project triggers them creates a 'last one in pays' problem. Proactive transmission planning, automated study tools, and grid-enhancing technologies such as dynamic line ratings can reduce delays. Large new loads, including data centres, now face their own connection queues.
Real-world examples
At home
Marcus joined a community solar co-op in Nova Scotia. He was surprised to learn the project would take more than two years to start, mostly because it was waiting for the utility to finish connection studies.
At work
Nadia is a development manager at a renewable energy company. Her wind project in the US Midwest sat in the queue for four years, and the final study assigned it a costly substation upgrade. The team added a battery to reshape its output and reduce the required upgrade.
Common confusions
- Everything in the queue will eventually be built. — Most queued capacity is withdrawn. Only a small share historically reaches operation.
- The queue is mostly fossil fuel plants. — In North America, most queued capacity is solar, storage, and wind.
- Queues are just bureaucratic delays. — Studies address real physical limits. The bottleneck is often transmission capacity, not paperwork alone.
For analysts
For any energy project timeline, I'd ask where it sits in the queue and what upgrades the studies identified. Interconnection risk is often the biggest unpriced risk in renewable energy investments.
History & origin
Grid operators have long studied new generators before connection, but queues stayed manageable when most new plants were large and few. Cheap solar, wind, and batteries changed that in the 2010s, as thousands of smaller projects applied, many speculatively. Lawrence Berkeley National Laboratory's annual 'Queued Up' reports documented the backlog: about 2,290 gigawatts were waiting in US queues at the end of 2024, and roughly 2,060 gigawatts at the end of 2025, a 10% drop driven mostly by withdrawals. Only about 13% of capacity that applied between 2000 and 2020 had reached operation by the end of 2025. FERC's Order 2023, issued that July, required grouped 'cluster' studies and stricter readiness rules. In my view, the queue is where climate targets meet the physical limits of transmission lines.