SMart Wind successfully installs Round 3’s first met mast




11 March 2019




Hornsea Wind Farm

New ‘Twisted Jacket’ foundation set to significantly reduce CAPEX

SMart Wind, the joint venture between Mainstream Renewable Power and Siemens Project Ventures, today announced the successful installation of the first meteorological mast in the 4GW Hornsea Zone. One of nine zones awarded licences by the Crown Estate in 2009 this is the first zone to install a met mast. The met mast uses the world’s first “twisted jacket” foundation for the offshore wind industry which was designed by Keystone Engineering. This novel foundation design, funded in partnership with the Carbon Trust and DONG Energy, aims to significantly reduce foundation CAPEX costs. The met mast will collect high quality wind data up to 103m above the sea using a full suite of metocean instruments including cup and ultrasonic anamometers, wind vanes, sea and air temperature and pressure sensors, and a wave height sensor.  This data will be collected throughout the coming years to inform the wind farm design activities and energy production estimates. Speaking today and RenewableUK’s annual conference, Secretary of State for Energy and Climate Change, Chris Huhne said: “I’m pleased to announce today that a project funded through the Offshore Wind Accelerator has been successfully installed with a met mast by the SMart Wind consortium, with funding support from DONG Energy. This kind of innovation will bring down the cost of offshore wind faster.” Andy Kinsella, Chairman of SMart Wind and CEO of Mainstream’s Offshore business commented: ’This is another first for SMart Wind and a clear demonstration that we’re fully committed to starting construction in 2014. Reducing the Cost of Energy is a key focus for SMart Wind and the new “twisted jacket” foundation is a practical and example of how we’re leading the way in terms of real cost reductions and innovation.’ Benj Sykes, Director of Innovation, at the Carbon Trust, said: “The installation of the ‘twisted jacket’ marks an important step for UK offshore wind in embracing foundation technology that could dramatically reduce construction costs. The Carbon Trust congratulates our Offshore Wind Accelerator partners Mainstream, DONG Energy and Keystone Engineering in successfully deploying what is a cost-effective design well suited to future mass production.” The Hornsea project has achieved the following milestones and is firmly on track to commence construction in 2014:

  • March 2010: Full suite of environmental surveys commenced.
  • April 2010: Ten Phase 1 consultation events took place.
  • September 2010: Grid connection obtained for first two 500MW projects (1GW in total)
  • May 2011: Appointed Fugro Geoconsulting Ltd  to carry out Geotechnical Investigation works
  • August 2011: Signed Agreements for Lease (AFLs) with The Crown Estate for the first two 500MW projects.


The “twisted jacket” prototype is a finalist in the Carbon Trust’s Offshore Wind Accelerator competition to find the most innovative and cost effective turbine foundation designs for deeper water conditions. HOCHTIEF Solutions AG Civil Engineering and Marine Works branch is the lead EPCI contractor for the construction and installation of the met mast. The company has supported SMart Wind from the beginning in achieving their targets. Under a separate agreement, University College Dublin, under support from Enterprise Ireland, and Fugro Structural Monitoring Limited will install structural instrumentation on the foundation to help further develop the ‘Twisted Jacket’ designs and give confidence that it is performing as expected. The “twisted jacket” prototype is one of four finalists from the Carbon Trust’s Offshore Wind Accelerator (OWA) foundations competition to find the most innovative and cost effective turbine foundation designs for deeper water conditions. The OWA is a collaborative RD&D programme between the Carbon Trust, DONG Energy, E.ON, Mainstream Renewable Power, RWE Innogy, ScottishPower Renewables, SSE Renewables, Statkraft and Statoil that aims to reduce the cost of offshore wind by 10%.

Related Project

Hornsea Wind Farm

Mainstream and Siemens Project Ventures JV (“SMart Wind”) successfully bid in The Crown Estate’s Round 3 leasing process in 2009 and was awarded the Hornsea Zone.  

SMart Wind continued to develop the fixed-bottom site and fully developed and consented Hornsea One and developed Hornsea Two (1.3+ GW).

The Hornsea Zone was sold to Ørsted in 2015 and the site size has subsequently increased from the initial award of 4 GW to 5+ GW. 

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