High Court considers relationship between planning permission under TCPA and the NSIP regime in solar farm appeals

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The following article considers the following case: R (on the application of (1) Durham County Council; (2) Hartlepool Borough Council) v Secretary of State for Levelling Up, Housing and Communities (D); Lightsource SPV 206 Limited and Lightsource Development Services Limited (IPs) [2023] EWHC 1394

Background and facts of the case

When does a solar farm become a Nationally Significant Infrastructure Project (“NSIP”) requiring a Development Consent Order (“DCO”) rather than planning permission under the Town and Country Planning Act 1990 (“TCPA”)? This was effectively the question before the High Court in this case, arising from a challenge by the two local planning authorities to the jurisdiction of the Planning Inspector to determine two solar farm appeals. The 50MW threshold for solar applications, below which the TCPA applies rather than the DCO regime, has been highly influential in the promotion of solar schemes and has led to a large number at the 49.9MW scale in order to avoid a potentially more arduous DCO application. In this case, the local authorities contended that two 49.9MW solar farms connecting to the same substation were in fact one NSIP and therefore should have been subject to a DCO application and not a TCPA application as was the case. On that basis, the local planning authorities submitted, the Planning Inspector had no jurisdiction to determine the applicant’s appeals.

Issues and judgment

The Court dealt with the question of whether the Planning Inspector had jurisdiction to consider the appeals, whether or not together they created an NSIP. This is a particularly interesting element to the case. As contended by the Secretary of State, the Court agreed the Planning Inspector had jurisdiction to consider the appeals even if they did constitute an NSIP – this was on the basis there is nothing in the TCPA which limits the granting of planning permission only in cases where it is required. i.e. the DCO regime under the Planning Act 2008 does not preclude a planning permission being granted under the TCPA for the same scheme, rather it simply states planning permission is not required in addition. Furthermore, the judge Mr Justice Chamberlain commented at paragraph 54 of the judgment that such a TCPA permission could indeed be implemented (despite the entire scheme being an NSIP) provided it was only built out to a capacity below the 50MW threshold.

The Court also determined that the two solar schemes were not a single NSIP and had correctly been applied for and appealed as two separate TCPA consents. The cables and substation were not part of the electricity generation infrastructure (only its transmission) and the two schemes could operate independently.


The Court’s finding that the two solar scheme were indeed two schemes rather than a single NSIP will likely be welcomed by solar developers seeking similar approaches to avoid the requirement for a DCO application. Scale is clearly relevant and if the scheme had the potential for three or more 49.9MW solar farms the preferable approach might well have shifted to creation of a single NSIP with a DCO application.

There are points of principle raised regarding the interaction between the TCPA and the DCO regime under the Planning Act 2008. This case has however created more debate than answers. Whilst it is correct that there is no overriding obligation to fully build out all consented works under a DCO or planning permission, the Planning Act 2008 does require a DCO to be secured where development “is or forms part of” an NSIP (section 31). The question follows, at what point is the NSIP created? The point it is consented or the point it is built and becomes operational and, in the case of a solar scheme, its generating capacity is above 50MW? For those familiar with DCO applications the clear line in the sand has always been where a DCO application is accepted giving confirmation that development consent is required under section 55(3)(c) of the Planning Act 2008. The Court rightly noted this does nothing to address the issue of developments potentially comprising an NSIP but being implemented without a DCO, in which circumstances the courts will be left to determine whether an NSIP was indeed in existence.

The issues raised in this case may return as site splitting remains an important consideration for solar developers – if generating capacity is to be maximised the relative burdens of the different routes to achieving planning permission must be acknowledged.  Added to this are the potential changes arising from revisions to the Energy National Policy Statements in particular EN-3 on renewable electricity infrastructure.

For more information on this article, please contact Thomas Ewings.

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