The UK’s National Energy System Operator (NESO) has completed its overhaul of the UK’s grid connection process.

The reforms removed speculative generation and storage schemes and introduced a readiness-based system intended to shorten connection timelines and allocate capacity more efficiently.

The overhaul had a noticeable impact on the country’s data center pipeline, with more than 100GW of large-scale demand projects, predominantly data centers, still in the pipeline. Rather than culling projects, projects were sorted by readiness and shifted into firm-capacity blocks extending mostly towards 2035, rather than before 2030.

The National Grid, the UK’s transmission and distribution operator, recently stated that data centers could account for up to nine percent of UK electricity demand by 2025, compared to 2.5-3 percent today.

For power generation projects, NESO confirmed that approximately 217GW of projects were placed in “Gate 1,” representing projects lacking consents, land rights, or clear progress, effectively removing them from the queue. NESO retained a pipeline of 238GW of projects for development to 2035, a huge fall from more than 700GW that was previously in the connections queue.

The process prioritized “protected” projects, including those with older offer dates of demonstrable readiness. Battery storage projects accounted for the bulk of the projects retained, with 83GW surviving the cull. Solar fared less well, with roughly 36GW removed, though several areas in northern and southwestern England and in South Wales still show capacity gaps. Offshore wind, nuclear, unabated gas, long-duration storage, and interconnectors were all deemed full or oversubscribed for the period to 2035.

In addition, as a result of the reforms, transmission-connected demand expanded noticeably. According to NESO estimates, around 13GW of firm demand can connect before 2030, with a further 86GW slated for connection between 2030 and 2035. Much of this is driven by hyperscale data center development and industrial electrification.

The reform results also reflected an uneven regional picture, with several technologies treated as “full” at a regional level. For example, Scotland was considered closed for new onshore wind development and is heavily constrained for new BESS projects. For data center developers, this could play a key role in their siting decisions, due to the lack of a uniform national picture.

Ofgem approved the reforms in April as a means to clear the connection queue of “zombie” projects and prioritize projects aligned with the country’s strategic energy plans.

The agreement is expected to support the UK government’s Clean Power Action Plan, which could see around £40 billion ($53.3bn) of investment into the clean energy sector between 2025 and 2030.

In addition, the reforms aimed to create an expedited route to market for data centers, which were classified as critical national infrastructure last September. Data centers in the UK market currently face long lead times for connection, around five to ten years on average, with some facing connection dates as far into the future as the 2030s.

The UK government has shown increased support towards the sector over the past year. In February, it announced that it would work with power companies to make up to 500MW of electricity available for new data center developments in each of its planned AI growth zones. The government has since announced the locations of four of its AI Growth zones.