The transaction gives Hydro a book gain of approximately NOK 350 million with accounting effect from June 1. The agreement with Oslo Pensjonsforsikring, a life insurance company wholly owned by the Oslo city authority, was first announced December 18, 2015.

The transaction does not include power supply network, which will continue to be operated by Hydro’s wholly owned subsidiary Herøya Nett AS.

For many decades, Herøya was Hydro’s largest and most important production site. Industrial activity began there in 1929 with the establishment of Eidanger Salpeterfabrikker. The site was gradually developed, first with production of fertilizer and fertilizer byproducts, and later with production of PVC and magnesium. At its peak in the 1960s, the site had 6,500 employees.