A full suite of environmental surveys of the floating offshore wind farm location and its surroundings is undertaken to determine the environmental impacts. These surveys establish the baseline for the assessment and allow impact modelling to be undertaken.

What it costs

About £4 million for a 450 MW floating offshore wind farm.

Who supplies them

APEM, ERM, Fugro, Natural Power, RPS, RSK and SLR.

Key facts

Environmental surveys are one of the first tasks to be undertaken at a potential offshore wind farm site and it can take two years or more before sufficient data is collected in order to apply for consent. Floating offshore wind farms have a greater emphasis on certain environmental surveys compared to fixed offshore wind farms. This is to understand and mitigate environmental impacts, if any, because of the larger sea bed usage.

The surveys include bird, fish, marine mammal, and habitat surveys as well as marine navigation studies, socio-economic surveys, commercial fishing, archaeology, noise analysis, landscape and visual assessment and aviation impact assessments.

Companies and developers recognise more detailed surveying can reduce costly consenting delays and post-construction environmental monitoring requirements.

Some surveys need to establish regional behaviours of wildlife, for example bird feeding and breeding patterns, and in these cases, data may need to be collected for several years. For highly mobile wildlife populations such as birds or sea mammals, it may be difficult to establish whether the predicted impacts during construction will be enduring.

Vessels and aircraft are used to collect the survey data. Surveys look at the distribution, density, diversity, and number of different species.

A challenge in the assessments is trying to understand the cumulative impacts of several wind farms, particularly when these are the subject of separate EIAs and consenting processes.

Some environmental surveys are undertaken by companies that also offer geological or hydrological surveys, in which case the work can be conducted from the same vessels in a single campaign.

Environmental surveys are typically undertaken by companies from the home market, partly because there is sufficient local resource and partly because some of the wildlife impacts are site specific and require detailed local knowledge and expertise.

Under the Offshore Wind Evidence and Change programme, The Crown Estate along with Natural England, Scottish Government and the Royal Society for the Protection of Birds has launched three new projects to protect and enhance marine biodiversity while encouraging offshore wind deployment. The projects are POSEIDON (Planning Offshore Wind Strategic Environmental Impact Decisions), PrePARED (Predators and Prey Around Renewable Energy Developments) and Remote Tracking of Seabirds at Sea.

Guide to a Floating Offshore Wind Farm