EPEn has recently completed a challenging interface risk assessment study for a major UK windfarm developer. The Offshore Wind Development project is planned in a congested area of the UK North Sea populated by Oil and Gas (O&G) installations and infrastructure. To support the Development Consent Order (DCO) process, EPEn performed a comprehensive technical and commercial interface opportunity and risk assessment, considering all phases of the project. The assessment was aimed at addressing, from the perspective of additional safety impacts, all considerations associated with O&G operations from interactions with the windfarm. The methodology applied follows the requirements of UK Offshore Safety Directive Regulator (OSDR) and provisions such as the HSE Safety Case Regulations (HSE, 2015) among others. The assessment was presented in a Technical Report and included as part of the DCO submission.