BEIJING - The use of environmental-friendly and energy-saving technologies, which is part of Beijing's efforts to host a green Olympics, has not raised the construction cost of Olympic projects, a city official said on Monday.

Yang Weiguang, deputy director of the Beijing municipal science and technology commission, told a press conference that most green technologies used in building venues and facilities for the Beijing Olympics were off the production line, which significantly reduced their cost.

The city authorities said under 13 billion yuan (US$1.9 billion) had been spent on construction of 31 competition venues, 45 training venues and other facilities for the Olympics.

It was the enterprises that were the leading forces in applying these green technologies in building these facilities, and through public bidding the Beijing 2008 Project Construction Headquarters Office had chosen the best enterprises with best green technologies, he said.

Yang said more than 190 environmental-friendly and energy-saving technologies had been incorporated in project construction, including water recycling, rainwater utilization, solar photovoltaic power generation and water source heat pump systems.

Many of these had been applied in building key projects such as the "Bird's Nest" National Stadium and the Olympic Village, Yang noted.

By employing water source heat pumps, the Olympic Village, already put into service on Sunday, will be able to save more than 60 million kilowatt hours of electricity per year and residents at the Village would be free of noise and flue gas emissions, according to Yang.

As for the "Bird's Nest", known for its unique latticework of interwoven steel, some 70 percent of its water supply came from recycled water, which would be used to wash the racetrack and water the plants, Yang said.