The 2018 IEP Pilot Report confirmed both the opportunity and the appetite for such a sector-based approach. It recommended the creation of a collaborative evidence hub to coordinate future research, share knowledge, and maintain a living record of lessons learned from the consenting of offshore wind.
Fast-forward to 2025, and that recommendation has been realised through the Offshore Wind Evidence and Knowledge Hub (OWEKH). Established by The Crown Estate through the Offshore Wind Evidence & Change Programme, and supported by ISEP, OWEKH brings together government, regulators, industry and technical experts to strengthen the evidence base that underpins environmental decision-making.
At the heart of OWEKH are its Evidence Review Notes (ERNs) - concise, collaboratively developed guidance documents that distil 25 years of learning from UK offshore wind Environmental Statements, stakeholder consultations, and post-consent monitoring. Each ERN sets out what the evidence shows, where consensus exists, and how assessment can be made more consistent and proportionate across projects.
The first of these, ERN: Environmental Impact Assessment, has now been published. It provides the overarching framework for the series, drawing on the review of 79 offshore wind EIAs to identify common weaknesses and propose nine core recommendations. These include standardising scoping through a simple three-tier system, clarifying terminology, improving proportionality of reporting, and using digital tools to make EIA clearer and more accessible.
Crucially, the ERN reaffirms a principle articulated in ISEP’s 2017 strategy: that proportionality is not about cutting corners, but about ensuring that effort, evidence, and attention are focused where they make the greatest difference.
Developed jointly by The Crown Estate and ISEP through the OWEKH Impact Assessment Technical Topic Group, the publication of ERN: EIA marks a milestone in a journey that began nearly a decade ago. It shows what can be achieved when practitioners, regulators and industry come together with shared purpose - to improve quality, reduce duplication, and build confidence in the EIA process.
With further topic-specific Evidence Review Notes in final drafts, OWEKH is well on its way to becoming the collaborative, evidence-led platform the IEP envisioned back in 2017.
