The Péribonka hydroelectric station is 160 km away from Alma and produces 405 MW. Thus, it supplies 85 000 households with electricity. The Péribonka hydroelectric developments project carried out by Hydro-Québec is located on the Péribonka River, a site with a well known potential. Macogep contributes to this peculiar project by executing control estimates and establishing construction methods. However, Macogep must take into consideration many constraints: specialized and tailor-made works, material transportation from one shore to another, works during winter season, Hydro-Québec’s distant location, etc. Macogep allows the company to clarify engineering documentation and optimize proposed design. Péribonka project has been completed successfully on-budget and three months ahead of schedule.