Atkins has previously designed substations for other Dong projects in the UK, including Burbo Bank Extension, Walney Extension and Race Bank.
Dong UK chairman Brent Cheshire said repeatedly using Atkins allowed for standardising the design, thereby reducing costs of the project.
Hornsea 1 is located 120 kilometres off the UK's east cost and is due online in 2020. It is part of the 4GW Hornsea Zone.
In February, Dong acquired all of Hornsea 1 from the Smart Wind consortium consisting of Mainstream Renewable Power and Siemens. Dong previously owned a 33% stake in the development. The UK government gave its consent for the project in December.
