Why do renewable projects wait years for grid connection?

Because interconnection is a real physical and administrative queue: until the studies for the projects ahead are finished, the ones behind cannot move. As of early 2024, the national interconnection backlog before the US Federal Energy Regulatory Commission (FERC) stood at roughly 2,600 GW — more than the entire installed generating capacity of the United States — and wind and solar applications make up the overwhelming majority.

The American numbers state the problem plainly. As of early 2024, the interconnection backlog before FERC totalled roughly 2,600 GW, exceeding the entire installed generating capacity of the United States, with wind and solar dominating the applications (Lawrence Berkeley National Laboratory, Queued Up: Interconnection Queues). Being in the queue is not the same as being built: many applications withdraw once network upgrade costs prove prohibitive, and some developers file multiple applications simply to hold positions. Even so, the figure exposes a genuine structural mismatch — grid upgrades are proceeding far more slowly than renewable projects are applying to connect.

The causes stack. First, ageing transmission lines lack headroom, so connecting one large new generator often triggers extensive line upgrades. Second, those upgrades are themselves construction projects requiring land acquisition and permits, on timelines comparable to building the power plant. Third, cost allocation rules — who actually pays for the upgrades — were historically unclear, so many projects withdrew after receiving large upgrade quotes, and each withdrawal changes the study results for the projects behind, triggering restudy.

Reform is under way. FERC Order 2023, issued in 2023, is the major overhaul of the US interconnection regime: it requires independent system operators (ISOs) to move from serial, project-by-project processing to cluster studies, in which a batch of projects is assessed for grid impact within a single study cycle. It also raises the barrier to entry with larger deposits, to discourage speculative placeholder filings. The effects will take several years to show up.

Interconnection is only one item on a long list. An offshore wind farm averages a decade from site survey to first power, because each stage has an incompressible duration. Wind resource assessment requires at least a full year of met mast data, ideally two to three. A complete environmental impact assessment (EIA) needs one to two years of baseline surveys covering birds, bats, vegetation, hydrology, noise and landscape, plus modelling and mitigation planning — commonly two to three years in total. Construction, by contrast, is the fast part: a 500 MWp ground-mounted solar plant typically takes 12 to 18 months to build.

Some 2,600 GW of projects sit in the US interconnection queue waiting to connect — as much as every generator currently running in the country. They are technically ready and financially backed; what holds them is the absorptive capacity of an ageing grid and a backlog of approvals.

This question is covered in depth in The Full Spectrum Every Energy Source Explained — A Singapore Perspective，第十一章 11.4