Wales: Developments of National Significance and PEDW

This article is about Wales only. Developments of National Significance are applications that Welsh Ministers determine instead of the local planning authority, under provisions inserted into the Town and Country Planning Act 1990 by the Planning (Wales) Act 2015. Applications are made to, and examined by, Planning and Environment Decisions Wales, and the local authority's role shifts from decision maker to consultee producing a local impact report.

The route is compulsory for development that meets the prescribed criteria. It is not a choice between the local and the national process, which is the first thing to establish about a project.

What brings a development into the national route

The test is not a judgement about importance. It is whether the development falls within a category and exceeds a threshold set out in regulations made under the 2015 Act.

Three features distinguish the regime from a local application. Welsh Ministers decide rather than the council. The examination is conducted by an appointed person through Planning and Environment Decisions Wales. And a set of other consents, prescribed as secondary consents, can be determined alongside the planning application rather than separately afterwards.

Policy is Welsh throughout. The development plan still applies, and above it sit Future Wales, the national development framework, and Planning Policy Wales with its Technical Advice Notes. The Well-being of Future Generations (Wales) Act 2015 also applies to the decision, which means the sustainable development principle and the well-being goals are part of the framework rather than background.

The categories and thresholds

The regulations prescribe the categories, and the one used most often is electricity generation. Onshore generating stations above 10 megawatts fall within the regime, and consenting for onshore generation in Wales is devolved up to 350 megawatts, above which the project is consented outside the devolved system.

Other prescribed categories cover certain transport, water and waste infrastructure, with their own thresholds. The list and the figures are set out in the regulations and they have been amended, so read the current statutory instrument rather than a summary when the project sits near a boundary.

Three practical checks are worth running at the outset.

1. Installed capacity as it will be consented, not as it is currently modelled, since a project designed at 9.9 megawatts to stay local can cross the threshold during detailed design.
2. Whether the proposal is one project or several, because splitting a scheme to avoid a threshold is both transparent and unhelpful.
3. Whether any element falls outside the devolved consenting regime altogether, which changes the whole programme.

Pre-application requirements

Pre-application work is not optional in this regime, and it is more prescriptive than for an ordinary application.

The applicant has to carry out pre-application consultation on a draft application, giving the community, the local planning authority and specified consultees a defined period to respond, and has to publicise the proposal. The responses then have to be reported, with an explanation of how they were taken into account, and that report is submitted with the application. An application without a compliant consultation report risks not being accepted.

Two points shape the programme. The consultation runs on a draft application, which means the environmental information, the drawings and the supporting documents have to be substantially complete well before submission. And the request to have secondary consents dealt with together has to be made as part of this stage, not later.

Treat the consultation report as a document the examination will read, rather than as a procedural formality. An appointed person who can see that a design change followed a consultation response is being shown something useful.

Secondary consents bundled with the application

The ability to deal with other consents in the same process is the main practical advantage of the regime, and it is underused.

Prescribed secondary consents can include listed building consent, hazardous substances consent and various drainage and highway related consents, with the list set out in regulations. Where a consent is included, Welsh Ministers determine it alongside the planning application, which removes the sequencing risk of obtaining permission and then discovering a separate consent will take another six months.

The limits matter as much as the scope. Not every consent a project needs is a prescribed secondary consent, and environmental permits in particular sit with the environmental regulator and run on their own timetable. Map every consent the project needs, mark which can be bundled, and programme the rest in parallel.

How the examination proceeds

After the application is accepted, the local planning authority prepares a local impact report setting out the effect of the development on its area. That report carries weight, and engaging with the authority before it is written is time well spent, because it is the authority's main opportunity to influence the outcome.

The appointed person then determines the procedure. Written representations, a hearing, an inquiry, or a combination, chosen according to the issues rather than the size of the project. Applicants sometimes assume an inquiry is inevitable on a large scheme and it is not. Where the issues are technical and the evidence is documentary, written representations can be both faster and better suited.

The appointed person reports to Welsh Ministers, who make the decision. That separation between examination and decision is a feature of the regime, and it affects how evidence should be presented, because the report has to be capable of carrying the argument to a reader who did not attend.

Scotland takes a different structural approach through its hierarchy of developments, which is worth comparing if you work across borders, and we set it out in the hierarchy of developments in Scotland. Northern Ireland's arrangements differ again, as described in the two-tier planning system in Northern Ireland.

Timescales and milestones

The regime sets periods for each stage rather than a single determination deadline, and the milestones are what a programme should be built around.

Check the current prescribed periods in the procedural order and in the Welsh Government's guidance, because they have been revised. Build float into the programme around acceptance and around the procedure decision, since both depend on third parties.

A reform is also in progress. The Infrastructure (Wales) Act 2024 provides for a unified infrastructure consent process intended to replace this regime for significant infrastructure projects. As at October 2026 the position on when that applies, and to which projects, should be verified before a programme is fixed around either route.

Whether the route suits your project

Where the thresholds are met the route is mandatory, so the real decision is how to use it.

Three judgements make the difference. Whether to bundle secondary consents, which almost always helps and requires the decision to be taken early. Whether to seek written representations rather than an inquiry, which depends on how much of the case rests on oral evidence. And how much to invest in the pre-application consultation, which is the stage with the largest effect on the examination and the one applicants most often compress.

One caveat on document preparation. AI-assisted drafting tools, including PlanScope, are grounded in English national policy and English local plans, so a Welsh application needs the Welsh policy framework checked and supplied by the reviewer rather than assumed. Our index of the 66 report types shows what each document covers, and for a Welsh scheme each draft should be read against Planning Policy Wales and the relevant Technical Advice Notes before it goes anywhere near a submission.

Enter your postcode on PlanScope to see which supporting reports a large infrastructure proposal is likely to need.

This is general guidance, not legal advice. Check the position with the local planning authority, Planning and Environment Decisions Wales or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.