Inner Dowsing

Location

The Inner Dowsing wind farm is situated approximately 5.2 kilometers offshore Ingoldmells, in the shallow waters at the entrance to The Wash, off the East Lincolnshire coast.

Development and Construction

• The project was initially developed as separate entities by AMEC and Renewable Energy Systems, but in 2003, Centrica Renewable Energy acquired both projects and merged them into a single development.
• Construction began in 2006 and was completed in 2009. Key contractors included Renewable Energy Systems Holdings for engineering, procurement, and construction services, Siemens Gamesa Renewable Energy for turbine supply and operations and maintenance, and Nexans for submarine cabling.

Turbines and Capacity

• The Inner Dowsing wind farm, along with Lynn, uses 54 Siemens SWT-3.6-107 wind turbines, each with a 3.6 MW nameplate capacity. This results in a total installed capacity of 194.4 MW for the combined project.

Foundations and Installation

• The turbines are installed on fixed monopile foundations. The foundations were installed using the vessel MV Resolution, and some drilling was necessary due to the geological conditions.
• The installation process included the laying of 72 kilometers of 36kV three-core submarine cables, with 40 kilometers of cable connecting the wind farm to the shore and 32 kilometers as array cables connecting the turbines.

Operations and Maintenance

• The wind farms were fully operational by March 2009. Siemens Gamesa Renewable Energy is the operations and maintenance contractor for the project.
• In 2011, Siemens replaced bearings on all 54 turbines due to corrosion issues identified in other wind farms. Additional maintenance contracts were awarded to companies like Cofely Fabricom GDF Suez and ABB for various repairs and electrical equipment maintenance.

Ownership

• Initially, the project was owned by Centrica Renewable Energy. In 2009, TCW acquired a 50% stake from Centrica. Later, in 2016, the ownership was transferred to a consortium including the Green Investment Bank (51%) and BlackRock (49%).
• As of 2024, Macquarie Asset Management is set to acquire the remaining 39.25% stake from BlackRock, gaining full ownership of the Lynn and Inner Dowsing wind farms.

Environmental Impact

• The combined wind farms supply enough clean energy to power approximately 130,000 households and offset around 500,000 tons of carbon dioxide emissions annually.

Financial Details

• The initial construction cost for the Lynn and Inner Dowsing wind farms was estimated at £300 million (or approximately €349 million).
• The 2016 sale of the wind farms to the consortium involving Green Investment Bank and BlackRock was valued at around £423 million.

Power Purchase Agreement

• The power generated from the project is sold to British Gas under a power purchase agreement for a period of 15 years.

The Inner Dowsing wind farm, as part of the Lynn and Inner Dowsing Offshore Wind Farms, has been a significant contributor to the UK's renewable energy sector since its commissioning in 2009.