On 21 August 2015, SMart Wind, the 50:50 joint venture between Mainstream and Siemens Financial Services concluded its sale to DONG Energy to continue the development of the 4 gigawatt Hornsea zone, awarded as part of The Crown Estate’s Round 3 programme in January 2010.

SMart Wind was established in 2009 and secured consent for the 1.2 gigawatt Project One in December 2014. Project One is located 120km off the Yorkshire coast and covering approximately 407 square kilometres. When completed, Project One will meet the electricity needs of around 800,000 homes in the UK.  As part of the development process, SMart Wind concluded a number of miletones including the installation of the world’s first twisted jacket foundation for its met mast, continuous community engagements and development of the highly successful SMart Futures school progamme.  The programme was established to educate school-goers on the importance of STEM subjects and the job opportunities from these subjects in renewable energy.