Liu Qi, deputy head of China's National Energy Administration, said on Thursday that both China and the United States shoulder the important mission of promoting energy security and global sustainable development.

"The two countries could further cooperation on a wide range of areas in the development of economic and energy sectors against the background of economic globalization," Liu told a forum on "Developing Effective Mechanisms for Energy Efficiency Implementation in China".

Jon Wellinghoff, acting chairman of the US Federal Energy Regulatory Commission, said enhancing energy efficiency in China and the United States presented the best opportunity to curb global warming, as the two countries together consumed approximately one third of world's energy.

"Tackling the energy and environmental challenges is in the mutual interests of our two nations. The two countries should work together in achieving our energy and environmental goals," Wellinghoff said.

Promoting energy efficiency was set as the sixth goal during the fifth round of China-US Strategic Economic Dialogue held in December in Beijing.

Energy efficiency was the best way to meet energy and environmental goals, while the two countries could work together in policy support, information exchange, and sharing best practices, Wellinghoff said.

Steven Chu, US Secretary of Energy, said in a videotaped address that the greatest challenges today were global and demanded global cooperation. The United States must work closely with China, India and other nations to fundamentally transform the way energy was used and produced.

"We need to make our homes, offices, and factories more energy efficient. And we must develop new sources of clean, renewable energy that will power the world economy for decades to come," Chu said.

The Chinese government has set a goal of reducing energy consumption per unit GDP by 20 percent in the five-year period from 2006 to 2010.

Energy intensity, the amount of energy it takes to produce a unit of GDP, fell 4.21 per cent year-on-year in 2008 in China, a larger decline than the 3.66 per cent recorded in 2007.