The National Stadium, more commonly known as the Bird's Nest and the main venue for the 2008 Beijing Olympic Games, on Wednesday signed a five-year strategic cooperation agreement with Hanergy Holding Group.

Wu Jingjun, general manager of the stadium, said the venue has embarked on a major branding operation and has already got expressions of interest from several leading companies.

"Naming rights for some stalls within the stadium is already underway," he said. "A good number of companies have cooperated with the stadium in various forms and Hanergy become the strategic partner due to its green concept for development."

Wu said the stadium is open to all kinds of cooperation from both domestic and foreign companies.

Li Hejun, chairman of Hanergy, said the company will use its advanced solar technology to upgrade equipment in the stadium to make it greener and cleaner.