By Jaime Llinares Taboada

SSE PLC said Wednesday that it has approved a final investment decision for its 443 megawatt Viking onshore wind farm project in Shetland, Scotland.

The FTSE 100 energy group said it is now awaiting regulatory approval for a 600 megawatt transmission connection from Shetland to Great Britain mainland, which is critical for Viking to proceed.

Viking will be the largest onshore wind farm in the U.K. in terms of power output--1.9 terawatt-hour a year--and will involve capital expenditure of 580 million pounds ($729 million), SSE said.

Write to Jaime Llinares Taboada at jaime.llinares@wsj.com; @JaimeLlinaresT