Some 1,200 delegates from 80 countries joined Chinese leaders at the Great Hall of the People, the seat of China's legislature, to discuss using solar power, wind energy and hydropower instead of coal and oil.
"Strengthening the development and use of renewable energies is a must for us to address the increasingly serious energy and environmental issues," Hu said in a statement that was read to the conference by Vice Premier Zeng Peiyan.
Participants in the conference included European Cabinet ministers and U.S. Energy Department officials.
China, the world's second-biggest producer of greenhouse gases after the United States, has promoted cleaner and renewable energy in hopes of reducing air pollution from its surging fossil fuel use and the potential security risks of growing dependence on imported oil.
The government says China relies on renewable energy for 7 percent of its needs but wants to raise that to 15 percent by 2020.
"With this Beijing conference, one of the world's boom regions is sending an important signal for sustainable development worldwide and a signal for global climate protection," said Jurgen Trittin, Germany's environment minister.
Worldwide, hydroelectric dams and other renewable sources account for 4 percent of power generation, with a total generating capacity of 160 gigawatts, according to Trittin. A terawatt is 1,000 gigawatts.
By 2050, that generating capacity is expected to grow by more than eight times to 1 terawatt, said Dan Arvizu, director of the U.S. Energy Department's National Renewable Energy Laboratory.
"But what we need is 20 terawatts," Arvizu said in a speech at the two-day conference. "We all need to do much more than any of us is currently doing."