In short
For most of the electricity system's history, projects joined a single queue for a grid connection and were served in the order they applied. By 2024 that queue held far more generation and storage than Great Britain could ever use, and viable projects were being offered dates in the late 2030s. Connections reform replaced first come, first served with a gated process. Projects now need to show they are ready and that they fit the country's energy plans before they get a firm connection date.
Why the queue needed reform
Applying for a connection used to be cheap and carried few obligations. Developers had good reason to apply early and often, for several sites and several technologies, and to hold on to an offer even if a project had stalled. The result was a queue of well over 700GW of generation and storage across transmission and distribution, several times what the system operator expects the country to need by 2035.
Because every project in the queue had to be studied in order, each new application was assessed against a backdrop of projects that were never going to be built. That pushed reinforcement works and connection dates further out for everyone. Battery storage and solar projects made up a large share of the queue, as they are quick to plan and develop.
Earlier fixes, such as queue management milestones and the transmission "two step" offer process, helped at the margins but didn't change the basic rule. In 2024 the government, Ofgem and NESO agreed a wider reform, set out in the Connections Action Plan alongside the Clean Power 2030 Action Plan.
How the gated process works
The design adopted is known in the industry as TMO4+ (Target Model Option 4, with extra changes). It splits a connection application into two stages.
Gate 1
A project applies with basic information and receives an indicative connection offer: a likely point of connection and an indicative date. Gate 1 does not reserve capacity or a place in the queue. It is meant to help developers judge whether a site is worth pursuing.
Gate 2
To get a firm offer with a confirmed date and point of connection, a project must pass two tests:
- Readiness. The main test is that the developer has secured the land for the project, usually through ownership, an option or an agreement for lease. Projects then have to meet planning and build milestones to keep their position.
- Strategic alignment. The project must fit within the capacity the government's plans call for, by technology and broad location. For the first round this was based on the Clean Power 2030 Action Plan, with separate allowances for projects needed by 2030 and those needed by 2035.
Projects that pass are placed in a new queue order, with connection dates set by when the network can take them. Projects that don't pass can stay at Gate 1 and reapply later, but don't hold firm capacity.
Applying it to the existing queue
The biggest step was running the same tests across the existing queue, not just new applications. Ofgem approved the code changes behind the reform in April 2025. NESO and the network companies then asked existing projects for evidence, assessed them, and began issuing revised offers. Some projects moved earlier, many moved later or lost firm capacity, and a large amount of speculative capacity left the queue.
What it means for distribution-connected projects
Most solar farms, batteries and smaller wind projects connect to a distribution network rather than to transmission. Reform still applies to many of them, because larger distribution projects affect the transmission network and need NESO's assessment. The DNOs aligned their own processes with the gated model through changes to the distribution codes. Smaller projects below the thresholds that trigger a transmission assessment are generally less affected, though DNOs have also been cleaning up their own queues.
If you're developing a distribution-connected project, the practical points are the same: have your land rights in place, track the milestones in your offer, and expect the DNO to ask for evidence. See getting a grid connection for the wider process.
Demand projects and data centres
The first round of reform was built around generation and storage, measured against the Clean Power 2030 plan. Demand projects, such as data centres, electrified industry and hydrogen electrolysers, were treated differently, because there was no equivalent national plan for how much new demand the country needs. Demand connection requests grew quickly in 2025 and 2026, led by data centres, and government, Ofgem and NESO have been working on how to prioritise demand that matters for growth and industrial strategy. Follow connections reform for the latest decisions.
What happens next
Future rounds will use NESO's Strategic Spatial Energy Plan, rather than the Clean Power 2030 plan alone, to decide how much of each technology is needed where. Expect continued debate over:
- how often application windows open, and how much capacity each allows;
- how demand projects are prioritised;
- whether milestones are enforced strictly enough to stop the queue growing again;
- how quickly the network can be reinforced to meet the dates now being offered.
Reform changes the order of the queue, not the amount of network. Faster connections depend just as much on building new transmission and making better use of existing networks through flexible connections.
Sources
Based on published material from NESO, Ofgem and the Department for Energy Security and Net Zero. Details change between rounds, so check NESO's connections pages and your network company for the rules that apply to your project.
Follow the news
Latest stories on Connections Reform, Clean Power 2030, Battery Storage. For terms, see the glossary; for key dates, the policy timeline.