Electricity Act 1989 - section 36 applications: guidance for applicants on using the design envelope

2. Background and purpose

2.1. Applicants have approached the ECU and MS seeking discussions on the degree of flexibility that would be considered appropriate in order to address the uncertainty often inherent in the context of onshore and offshore wind applications.

2.2. The ECU and MS continue to expect applicants to provide full details of proposed developments in applications and to reflect those details in the EIA report submitted with the application. Applicants must demonstrate that the likely significant environmental effects of the proposal have been properly assessed, and proposals require to be clearly defined and sufficiently detailed to enable determination of an application. The design envelope assessment approach should only be used where it is necessary and should not be treated as an opportunity to provide insufficient detail in the application documentation.

2.3. It is also recognised that in some instances, the nature of the proposed development and evolving technology mean that some aspects of the final project are yet to be settled in precise detail at the time that the application is submitted (such as the precise location of certain types of infrastructure, the foundation type, the size of certain structures or the turbine model). Where that is the case and some details are still the be finalised, the design envelope approach can be employed for such applications to enable a degree of flexibility and address these uncertainties. Through the design envelope approach, the application can set out parameters for the proposal including the maximum extents of the proposal and can assess on that basis what the likely worst case effects of the proposal may be. The detailed design of the project can then vary within this 'envelope' to ensure that the project as-constructed has been properly assessed. The approach taken must be sufficient to enable a proper assessment of effects in the context of the receiving environment.