French energy company Engie has partnered with Susi Partners, a Swiss investment fund specialising in renewable energy infrastructure, to build the 208MW Tonstad wind farm on the eastern side of Lake Sirdal, in Sirdal and Flekkefjord municipalities, in Southern Norway.

Engie sold 80% interest in Tonstad Vindpark, the project company that holds the license to build and operate the Tonstad onshore wind farm, to Susi Partners in June 2018.

Engie retains the remaining 20% stake and will be responsible to manage the construction as well as provide operational support for the project.

Turbine supply contract for the wind farm was awarded to Siemens Gamesa in August 2018, while the first turbine was erected at the site in July 2019.

Expected to commence operation in early 2020, the Tonstad wind farm will generate approximately 7000GWh of electricity a year, while offsetting approximately 180,000 tons of CO2 emissions.

Tonstad will be one of the biggest wind farms in Norway, upon completion.

Tonstad wind farm make-up

The 208MW Tonstad wind farm will comprise 51 SWT-DD-142 onshore wind turbines from Siemens Gamesa, mounted on 129m-high tubular steel towers.

Each direct drive turbine, with 142m rotor diameter and three 69.3m-long low-weight hybrid carbon blades, will have a swept area of 15,800m².

Designed to operate between 50Hz and 60Hz frequencies in low-wind onshore locations, each turbine of the Tonstad wind farm will have a rated capacity to produce up to 4.1MW.

Electricity transmission from Tonstad wind farm

The onshore wind farm will be grid-connected through a new 132kV transmission line connecting the Ertsmyra transformer station at Tonstad.

Power purchase agreement (PPA) for Tonstad wind farm

Hydro Energy, a wholly-owned subsidiary of Norsk Hydro, will offtake the entire electricity output from the Tonstad wind farm under a 25-year green power purchase agreement (PPA) signed with Tonstad Vindpark in July 2018.

Securing the supply of an estimated 0.7TWh of annual electricity output of the wind farm from 2020 to 2045, the PPA will help Norsk Hydro to produce approximately 50,000t of aluminium a year at its Norwegian plants using clean renewable energy.

Tonstad wind farm financing details

Susi Partners provided financial structuring support for the Tonstad wind power project.

Thommessen, a law firm based in Norway, assisted Engie in the sale of 80% of the shares in the power project to Susi Partners, whereas Wikborg Rein, another Norwegian law farm, assisted Susi Partners for the financial agreement on the wind farm concluded with Engie, in June 2018.

Germany-based company Landesbank Baden-Wuerttemberg (LBBW) provides the project debt financing package for the wind farm.

Contractors involved with the Tonstad wind project

Siemens Gamesa was awarded the contract to supply 51 SWT-DD-142 wind turbines for the Tonstad wind farm in August 2018.

The contractual scope also includes long-term maintenance agreement for the wind farm.