My colleague Neil Collar blogged yesterday on the decision in the Kirkby Moor Wind Farm appeal, whose owners had applied for a life extension of the original 25 year consent to 2027.

One critical aspect of the decision was the inspector's interpretation of the National Planning Policy Framework (NPPF) introduced in England this year. It provides at Footnote 49 that:

"a proposed wind energy development...should not be considered acceptable unless...following consultation, it can be demonstrated that the planning impacts identified by the affected local community have been fully addressed and the proposal has their backing."

This is the form of words introduced originally by the written ministerial statement (WMS) issued on 18 June 2015. It has largely halted new windfarm development in England as the test is so difficult to meet.

However, there is one important difference from the WMS. Footnote 49 starts with the phrase:

"Except for applications for the repowering of existing wind turbines"

We might refer to this exception as the 'repowering exception'. If it applies, the test for approving an application is the same test that applies to all renewable and low carbon applications, namely that set out in paragraph 154(b):

"local planning authorities should...approve the application if its impacts are (or can be made) acceptable"

This is quite a different test, and as the Kirkby Moor decision illustrates, one which is readily capable of being met.

The question is the scope of the repowering exception. The term itself is not defined in the NPPF but the Kirkby decision provides some useful guidance on its interpretation. The inspector had to decide if life extension fell within the meaning of "repowering". The Council argued that the proposed life extension was not a repowering but a proposal for a new windfarm on the site. However, the inspector held that repowering included life extension, based on his finding that the wind industry used the term as 

"an umbrella term covering replacement, replanting and extension of life".

The effect of this decision therefore is to define the repowering exception broadly. Of the face of it, the term includes a repowering which replaces, for example, an existing 10 turbine 10MW windfarm with a 5 turbine 20MW windfarm. With a current installed onshore wind capacity in England of around 2.9GW, it appears feasible that repowering could potentially increase installed capacity in England above 6GW.

Given that the term "repowered" is not defined in the NPPF, we expect further dispute as to the scope of the repowering exception. For example, if the proposed new development falls partly outside the redline boundary of the existing windfarm, would that be repowering of the "existing wind turbines"?

Ministers may also choose to provide clarification. And of course the Kirkby case could yet be appealed. Given the extent of repowering potential in England, a lot depends on the scope of the repowering exception.