The Critical Path: How to Avoid Grid Connection Delays on Your Next Project

The mistake most developers make

The most common mistake we see is treating the grid connection as a procurement task rather than a design task. Developers will spend months working on their planning application, their financial model, their EPC tender, and only pick up the phone about the grid connection once everything else is in place.

By that point, the connection timeline has already become a constraint. It cannot be optimised; it can only be managed.

“We should have started the grid conversation six months earlier.” We hear this on almost every project where delays have occurred.

The solution is to treat the grid connection as part of the critical path from day one, not an afterthought once planning is secured.

What the critical path actually looks like

A well-managed grid connection for a medium-to-large project typically follows this sequence:

Stage What needs to happen
Feasibility Confirm available capacity at the nearest substation. Identify the likely connection voltage. Understand queue position and indicative timescales.
Pre-application Engage the DNO or NESO early. Submit a pre-application enquiry if available. Commission a grid impact study.
Formal application Submit a complete, accurate application. Incomplete applications are one of the biggest sources of delay.
Offer and acceptance Review the offer carefully, particularly the assumed works, cost, and programme. Accept within the deadline or risk losing your queue position.
Design and procurement Begin procuring long-lead items (transformers, switchgear) as early as possible. 50-week lead times are common.
Construction Coordinate site works with the DNO programme. Delays on either side affect the other.
Commissioning Allow sufficient time for testing and energisation. This stage is often underestimated.

 

The transformer problem

If there is one procurement issue that catches developers out more than any other right now, it is transformer lead times.

UK and European transformer manufacturers are running at full capacity. Lead times for the kind of high-voltage transformers needed for grid connection projects, particularly 66kV and above, are regularly running at 50 weeks or more. Some specialist units are taking longer.

The implication is straightforward: if you wait until your grid connection offer is accepted before you start the procurement process, you are almost certainly adding 6 to 12 months to your programme.

The developers and EPC contractors who are managing this well are doing two things:

  • Reserving manufacturing slots early, sometimes before the grid connection offer is formally accepted
  • Working with EPC partners who have established relationships with equipment manufacturers and can move quickly

This is one of the areas where having the right contractor involved early, rather than just at the procurement stage, makes a measurable difference to the programme.

Aligning your grid connection with planning

One of the most common causes of project delay that does not get talked about enough is the misalignment between planning consent and grid connection timelines.

A planning application for a battery storage project or solar farm typically takes 12 to 18 months. A grid connection application, depending on the complexity and queue position, can take a similar amount of time, but they do not always run in parallel.

If your planning consent arrives before your grid connection offer, you may be sitting on an approved project with no way to connect it. If your grid connection offer arrives first and you have not accepted it in time, you lose your queue position.

The key is to understand both timelines from the outset and manage them as an integrated programme, not two separate workstreams. This means involving your grid connection and EPC team at the same time as your planning consultants, not after them.

Planning and grid connection are two sides of the same coin. Managing them separately is one of the most avoidable causes of project delay.

What good looks like

The projects we see run most smoothly share a set of characteristics that are worth spelling out:

  • The grid connection strategy is defined at feasibility stage, not at financial close
  • Pre-application engagement with the DNO happens before the formal planning submission
  • Long-lead equipment procurement is started as soon as technically possible
  • The EPC contractor is involved in the design process, not just handed a finished design to build
  • There is a single, shared programme covering planning, grid connection, and construction with clear dependencies between them

None of this is complicated. But it does require a shift in how grid connections are treated, from a box to tick to a discipline to manage.

How TMS Grid can help

TMS Grid specialises in grid connection design, ICP/IDNO works, and HV construction for battery storage, solar, and data centre projects across the UK. We work with developers from feasibility through to commissioning, which means we can help identify and manage connection risks before they become programme problems.

If you have a project in development and want to understand your grid connection options, or if you are already experiencing delays and need to find a way through, we would be happy to talk.

 

Grid connection delays are one of the most common and most avoidable causes of project overruns in the UK renewables and infrastructure sector. Here is what causes them, and what developers can do about it.

If you have ever been involved in a battery storage, solar, or data centre project in the UK, you will know the feeling. The planning application is in. The site is secured. The funding is ready. And then you hit the grid.

Suddenly, what looked like an 18-month build programme becomes a 28-month one. Not because of anything on site, but because of a queue, a capacity issue, or a process that nobody flagged early enough.

Grid connection delays are not inevitable. But they are extremely common, and the developers who avoid them tend to have one thing in common: they start thinking about the grid connection much earlier than everyone else.

The developers who avoid grid delays do not get lucky. They get organised and they get the right people involved at the right time.

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TMS GRID | INDUSTRY INSIGHT | MARCH 2026

The Critical Path: How to Avoid Grid Connection Delays on Your Next Project

If you have ever been involved in a battery storage, solar, or data centre project in the UK, you will know the feeling. The planning application is in. The site is secured. The funding is ready. And then you hit the grid.

Suddenly, what looked like an 18-month build programme becomes a 28-month one. Not because of anything on site, but because of a queue, a capacity issue, or a process that nobody flagged early enough.

Grid connection delays are not inevitable. But they are extremely common, and the developers who avoid them tend to have one thing in common: they start thinking about the grid connection much earlier than everyone else.

The developers who avoid grid delays do not get lucky. They get organised and they get the right people involved at the right time.

Why do grid connections take so long?

The UK electricity grid is managed by a network of Distribution Network Operators (DNOs) and, at the highest voltage levels, the National Energy System Operator (NESO). When you apply for a new grid connection, whether for a 50MW battery storage system or a new data centre substation, you join a queue.

That queue has grown significantly over the last few years, driven by the rapid growth of renewable energy, electric vehicle charging infrastructure, and large-scale data centres. In some parts of the country, that queue is now years long.

But the queue itself is not the whole story. Delays also come from:

  • Incomplete or incorrect applications, which get kicked back and restart the clock
  • Design changes late in the process, which can trigger a full re-assessment
  • Procurement delays for high-voltage equipment, particularly transformers and switchgear
  • Coordination issues between the grid connection and the planning consent
  • Underestimating the complexity of the connection voltage or substation configuration

 

The good news is that most of these are avoidable with the right preparation.

The mistake most developers make

The most common mistake we see is treating the grid connection as a procurement task rather than a design task. Developers will spend months working on their planning application, their financial model, their EPC tender, and only pick up the phone about the grid connection once everything else is in place.

By that point, the connection timeline has already become a constraint. It cannot be optimised; it can only be managed.

“We should have started the grid conversation six months earlier.” We hear this on almost every project where delays have occurred.

The solution is to treat the grid connection as part of the critical path from day one, not an afterthought once planning is secured.

What the critical path actually looks like

A well-managed grid connection for a medium-to-large project typically follows this sequence:

Stage What needs to happen
Feasibility Confirm available capacity at the nearest substation. Identify the likely connection voltage. Understand queue position and indicative timescales.
Pre-application Engage the DNO or NESO early. Submit a pre-application enquiry if available. Commission a grid impact study.
Formal application Submit a complete, accurate application. Incomplete applications are one of the biggest sources of delay.
Offer and acceptance Review the offer carefully, particularly the assumed works, cost, and programme. Accept within the deadline or risk losing your queue position.
Design and procurement Begin procuring long-lead items (transformers, switchgear) as early as possible. 50-week lead times are common.
Construction Coordinate site works with the DNO programme. Delays on either side affect the other.
Commissioning Allow sufficient time for testing and energisation. This stage is often underestimated.

 

The transformer problem

If there is one procurement issue that catches developers out more than any other right now, it is transformer lead times.

UK and European transformer manufacturers are running at full capacity. Lead times for the kind of high-voltage transformers needed for grid connection projects, particularly 66kV and above, are regularly running at 50 weeks or more. Some specialist units are taking longer.

The implication is straightforward: if you wait until your grid connection offer is accepted before you start the procurement process, you are almost certainly adding 6 to 12 months to your programme.

The developers and EPC contractors who are managing this well are doing two things:

  • Reserving manufacturing slots early, sometimes before the grid connection offer is formally accepted
  • Working with EPC partners who have established relationships with equipment manufacturers and can move quickly

This is one of the areas where having the right contractor involved early, rather than just at the procurement stage, makes a measurable difference to the programme.

Aligning your grid connection with planning

One of the most common causes of project delay that does not get talked about enough is the misalignment between planning consent and grid connection timelines.

A planning application for a battery storage project or solar farm typically takes 12 to 18 months. A grid connection application, depending on the complexity and queue position, can take a similar amount of time, but they do not always run in parallel.

If your planning consent arrives before your grid connection offer, you may be sitting on an approved project with no way to connect it. If your grid connection offer arrives first and you have not accepted it in time, you lose your queue position.

The key is to understand both timelines from the outset and manage them as an integrated programme, not two separate workstreams. This means involving your grid connection and EPC team at the same time as your planning consultants, not after them.

Planning and grid connection are two sides of the same coin. Managing them separately is one of the most avoidable causes of project delay.

What good looks like

The projects we see run most smoothly share a set of characteristics that are worth spelling out:

  • The grid connection strategy is defined at feasibility stage, not at financial close
  • Pre-application engagement with the DNO happens before the formal planning submission
  • Long-lead equipment procurement is started as soon as technically possible
  • The EPC contractor is involved in the design process, not just handed a finished design to build
  • There is a single, shared programme covering planning, grid connection, and construction with clear dependencies between them

 

None of this is complicated. But it does require a shift in how grid connections are treated, from a box to tick to a discipline to manage.

How TMS Grid can help

TMS Grid specialises in grid connection design, ICP/IDNO works, and HV construction for battery storage, solar, and data centre projects across the UK. We work with developers from feasibility through to commissioning, which means we can help identify and manage connection risks before they become programme problems.

If you have a project in development and want to understand your grid connection options, or if you are already experiencing delays and need to find a way through, we would be happy to talk.

Get in touch:
Email: enquiries@tmsgrid.com | Phone: +44 191 417 2222 | www.tmsgrid.com

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