China reduced its greenhouse gas emissions by 1.5 billion tonnes between 2006 and 2010, the biggest decrease of any country in the period, according to a new report.

The country's energy intensity in 2010, or energy consumption per unit of gross domestic product (GDP), reduced by 19.1 percent from the level of 2005, equal to saving the energy consumption of 630 million tonnes of standard coal, and resulting in the emission of 1.5 billion fewer tonnes of greenhouse gas, said the report on China's low-carbon development, published by the Institute of Global Low-carbon Economy, University of International Business and Economics, and the Social Sciences Academic Press.

Although China has become a major carbon emitter, it has realized the biggest carbon emission reduction across the world, said a press release from the report's research team on Saturday.

"The carbon emission reduction policy in China has been one of the strictest and most effectively implemented in the world," the release said.

Over the five years, the country managed to sustain an annual average economic growth of 11.2 percent, with an annual energy consumption increase of 6.6 percent, according to the report.

Efforts to shut down energy-inefficient and highly polluting thermal power plants led to about 50 million tonnes of carbon emissions being cut, the report said.

From 2007 to 2009, the country closed thermal power plants with a total capacity of 54 million kw.

China also shut down energy-inefficient industrial projects such as steel factories, cement plants and coal-mining companies over the past five years, according to the report.

It launched 10 major energy-saving programs, including updating coal-fueled industrial boilers, improving the energy efficiency of the heating supply network, promoting green residential and office buildings and installing low-carbon public lighting systems.

The programs helped the country save the equivalent energy consumption of 240 million tonnes of standard coal, equal to a cut of about 550 million tonnes in carbon emissions, the report said.

Efforts to increase the use of alternative energies and forestation programs also contributed to carbon emission control, it added.

Non-fossil energies accounted for 8.3 percent of the country's annual energy consumption in 2010, up from 7.5 percent in 2005.

Forest coverage in China reached 20.36 percent in 2010, up from 18.2 percent in 2005.

In the next five years, the country has promised to further reduce energy intensity by 16 percent and increase the ratio of non-fossil energies to 11.4 percent of the annual energy consumption.

Also, it aims to cut the carbon dioxide emission per unit of GDP by 17 percent from the level of 2010, which is the first time China included such a goal in its five-year economic and social development plan.

Xuan Xiaowei, a research fellow from the Development Research Center of the State Council and one of the report's authors, admitted that the country would face great challenges to fulfill these three goals.

The key to realizing them is to further reduce the energy intensity of the heavy industrial sector, he said.

The report also noted that, over the past three decades, China has made great progress in reducing energy intensity but the energy consumption structure has barely changed, with coal as the major fuel.

More efforts should be made to introduce alternative energies such as solar power, wind power, nuclear power and hydropower, it said.