Scroby Sands

Scroby Sands Wind Farm Profile

Location

The Scroby Sands Wind Farm is situated on the Scroby Sands sandbank in the North Sea, approximately 2.5 kilometers off the coast of Great Yarmouth, Norfolk, on the east coast of England, UK.

Developer and Operator

The wind farm was originally developed by E.ON UK, specifically by its division Powergen Renewables Offshore. It is currently owned and operated by RWE Renewables.

Capacity and Turbines

The wind farm consists of 30 Vestas V80 wind turbines, each with a capacity of 2 megawatts, totaling an installed capacity of 60 megawatts. These turbines are capable of producing enough electricity to power approximately 41,000 to 48,000 UK households.

Construction and Commissioning

• The project began with site assessments in 1993-1994 and the installation of an anemometry mast in 1995.
• The construction phase started in November 2003, with foundation installation commencing in November 2003.
• Turbine installation was completed by A2SEA and Seacore, taking about eight weeks.
• The wind farm was commissioned in March 2004, following commercial completion in December 2004.

Infrastructure

• Each turbine is supported by a monopile foundation, which are 4-meter diameter steel tubes, up to 50 meters long, hammered about 30 meters into the sea bed.
• The turbines have three 40-meter blades and a nacelle housing the gearbox, generator, and transformer. The turbines stand 60 meters above the mean sea level.
• The offshore cabling was laid by CNS Ltd and buried up to 3 meters deep in the sea bed, with some sections overlaid by concrete mattresses.

Environmental Considerations

• The construction was planned to minimize impacts on seal populations, with work progressing from south to north to avoid seal haul-out areas during pupping periods.
• Monitoring by the Centre for Environment Fisheries and Aquaculture Science (CEFAS) included seabed surveys and deployment of seabed landers to assess impacts on coastal processes and benthic environments. The studies showed some changes in seabed bathymetry and sediment transport but no significant long-term effects on common seal or grey seal populations.

Challenges and Innovations

• The wind farm is built on a sandbank that shifts significantly, which has led to issues with access for maintenance. To address this, an amphibious vessel, the CRC Walrus, was designed and built to reach the turbines in shallow waters.
• The shifting sands have also caused some turbines to become isolated from service vessels, necessitating innovative solutions for maintenance.

Tourism and Community Impact

• The wind farm has an information center that, until its closure in late 2019, attracted around 35,000 visitors per year, making it a local attraction. The center was refurbished by E.ON in 2018 before its closure.

Performance and Impact

• The wind farm generates approximately 157,680 MWh of electricity annually, offsetting around 67,802 tons of carbon dioxide emissions per year.
• Between 2005 and 2010, the capacity factor of the wind farm was between 26 and 32%, with some years seeing production below forecast due to technical issues such as bearing and generator failures.

Licensing and Financials

• The project was part of the Crown Estates Round 1 licensing awards and involved a capital grant worth £10 million, reducing the cost to E.ON UK by £0.167 million per megawatt. The total project cost was £75.5 million, including a decommissioning provision of £1.617 million.

In summary, Scroby Sands Wind Farm is a pioneering offshore wind project in the UK, known for its innovative solutions to environmental and logistical challenges, and its significant contribution to renewable energy production.