The complete guide to grid connection queues and flexible connections

The complete guide to grid connection queues and flexible connections

Learn why grid connection queues have become one of the biggest barriers to new generation, storage and demand growth, and what developers can do about it.

Across almost every major electricity market, the same bottleneck has emerged. Generation, storage and, increasingly, large demand projects such as data centres are queuing for years before they can connect to the network.

Renewable generation, battery storage and electrified demand are all expanding faster than transmission and distribution networks can be built or upgraded to accommodate them. For developers, investors and large energy users, understanding how connection queues work, and what options exist to work around them, has become essential to project planning.

This guide explains why connection queues exist, how large the problem has become, what reforms are underway, and what flexible connections and on-site strategies can offer in the meantime.

Why connection queues exist

Before any new generation, storage or large demand project can connect to the electricity network, the system operator must study its impact: whether existing infrastructure can accommodate it safely, and what network upgrades, if any, are required first. These studies, and the physical works that often follow them, take time, and in most markets, projects are assessed in the order they applied. This process, sometimes called an interconnection queue, was built for an era when the volume of applications was modest and predictable.

In the UK, demand for electricity is expected to increase from 120GW to 300GW by 2035. The Climate Change Committee’s Balanced Pathway scenario for delivery of net zero by 2050, which has informed the Government’s plan for delivering the Sixth Carbon Budget, projects annual electricity demand to be around 50% higher than pre-Covid levels in 2035 and 100% higher by 2050. But a report published by the Environmental Audit Committee in May 2024, concluded that many planned renewable energy projects are being hampered by persistent problems accessing the electricity grid. These include slow connections, limited capacity, inappropriate planning regulations and market uncertainty.

Demand to access the grid is high; the current queue to connect contains more than twice the amount of generation required to meet the Government’s target of decarbonising the energy system by 2035. But projects being unable to access the grid could make that target harder to achieve. The energy regulator Ofgem and the Electricity System Operator (ESO) have attempted to speed up the system by requiring projects to meet key “milestones” like securing planning permission. Businesses that fail to meet such milestones could lose their place in the queue. However, the Committee’s report finds that early evidence suggests these changes have not yet reduced the length of the connection queue.

According to Ofgem, over half of generation customers in the transmission queue today (i.e. holding connection agreements) have a connection offer date at least 5 years in the future, with over 10% due to wait 10 years or more. This trend is continuing, with 70% of recent applicants (offered in the last 12 months) receiving connection dates that are 5 or more years away and over a quarter receiving connection dates beyond 2032 – some beyond 2037. Many of these are large, complex projects with long lead times, but the wait is still too long.

The Environmental Audit Committee recommended that the Government and Ofgem actively monitor and streamline initiatives designed to deliver grid connections faster. In particular, it recommends that Ofgem review its milestone queue reforms, with a focus on advancing projects that are demonstrably ready to the front of the queue. The report also found that the planning system risks being a “bottleneck” to the rollout of energy infrastructure, as local authorities often lack the resources or in-house knowledge to accelerate clean energy projects. It recommends the Government develop a plan to ensure local authorities have the personnel and expertise they need to reach planning decisions quickly while engaging with local communities.

Across the USA, the waitlists for large projects to connect to the grid have also expanded significantly, with over 1,400GW of wind and solar power awaiting connection. PJM came in last out of seven regions, with a grade of D-, in the Generation Interconnection Scorecard report prepared for Advanced Energy United.

The report, published in February 2024, found that in a nation with “agonisingly slow” grid connection processes, the PJM process of studying and green-lighting new requests to connect to the grid was the slowest, with the most unpredictable timelines. ERCOT and CAISO processes score the best, each receiving a B. ERCOT received high scores for the quantity of resources that completed its interconnection process at a reasonable cost, but the lack of proactive regional transmission planning to upgrade its transmission system is a major impediment to development of new generation resources. CAISO was awarded high marks for its proactive upgrades to its transmission system but is rated lower than ERCOT for its overall interconnection process results due to recent delays in completing interconnection studies and agreements and constructing the necessary grid facilities.

A recurring theme across markets is that the queue substantially overstates what will actually be built. A large share of queued projects, often the majority in the most congested zones, are ultimately withdrawn or never reach commercial operation, having applied speculatively or being unable to proceed once true connection costs and timelines become clear.

Why queues have grown so fast

• the rapid growth of wind, solar and battery storage, all of which require new grid connections at a scale and pace networks were not originally designed for
• “first come, first served” queuing models allowed large volumes of speculative or non-viable projects to occupy queue positions for years
• recent growth in large demand applications, particularly from data centres, which in some markets has outpaced generation growth in the queue
• ageing transmission infrastructure that was not built for today’s pattern or scale of connection requests

The result is a queue that is simultaneously enormous and unreliable as a guide to what capacity will genuinely arrive, and when.

Reform efforts underway

Recognising that the traditional queue model has broken down, system operators and regulators across are pursuing significant reforms.

• Great Britain’s TMO4+: approved by Ofgem in 2025, Great Britain’s TMO4+ reform replaces the “first-come, first-served” model with a “first ready and needed, first connected” process. Projects must demonstrate genuine readiness and alignment with the government’s Clean Power 2030 capacity plan to retain a place in the queue, a change that has already resulted in a large share of previously queued capacity being deprioritised. The government has separately proposed further reforms specifically targeting demand-side connections, including data centres, following a sharp rise in speculative demand applications.
• PJM’s cluster studies and colocation rules: PJM has moved to a “cluster study” process intended to process applications in batches rather than sequentially and has introduced new frameworks for data centres seeking to co-locate directly with generation assets, following a federal regulatory order in December 2025 aimed at clarifying the rules for these arrangements.
• ERCOT’s large load frameworks: ERCOT and other system operators are developing distinct interconnection pathways for large loads, including options where demand accepts curtailment risk in exchange for faster or lower-cost connection, an approach increasingly referred to as flexible or non-firm connection.

Flexible connections: a way around the queue

One of the most consistent themes across these reform efforts is the emergence of flexible, or non-firm, connections as an alternative to waiting for a fully firm grid connection. Rather than always guaranteeing unconstrained access to the network, a flexible connection allows a project to connect sooner, on the condition that it accepts curtailment during periods when the network is constrained.

For many developers, particularly those with storage or demand-side flexibility already built into their project, this trade-off is increasingly attractive. Connecting years earlier, in exchange for accepting a modest, and often predictable, level of curtailment risk, rather than waiting for a firm connection that may not arrive for the better part of a decade.

Other paths for developers

Beyond flexible connection offers, developers facing long queue delays have several options to reduce their exposure to grid connection timelines:

• on-site generation, reducing reliance on grid capacity for baseline power needs
• battery storage, which can smooth demand peaks, reduce the network capacity a site needs to request, and often qualifies for faster or different connection treatment than pure demand
• curtailable or flexible interconnection agreements, accepting defined curtailment risk in exchange for an earlier connection date
• demand response and virtual power plant (VPP) participation, which can reduce peak import requirements enough to change the scale, and sometimes the category, of connection a project needs to apply for

Developers can combine several of these, reducing both the size of the connection being requested and the risk associated with accepting a non-firm offer.

Why GridBeyond’s approach to grid connection challenges is different

Grid connection queues are a capacity and risk problem, and flexibility is one of the tools that can address both sides of it at once. Reducing the peak capacity a project needs to request and providing the demand-side or storage response needed to accept curtailment risk safely once a flexible connection is secured.

GridBeyond’s Designer Studies allow developers to model these trade-offs before committing to a connection strategy, quantifying how battery storage, on-site generation or demand-side flexibility would change the capacity, and therefore the queue position, a project realistically needs to request.

Once a project is operating, the GridBeyond platform provides the real-time optimisation needed to manage curtailment exposure under a flexible or non-firm connection agreement, turning what would be risk into an asset that can be actively managed and monetised, through participation in demand response, wholesale and balancing markets.

For developers and large energy users facing multi-year connection delays across Great Britain, ERCOT and PJM alike, this combination, reducing requested capacity, accepting and actively managing curtailment risk, and monetising the flexibility that results, is increasingly the fastest realistic route to securing power.