BEIJING, April 28 -- China will become the world's second-largest shale gas producer by 2035, behind only North America, a report by energy giant British Petroleum (BP) predicted on Tuesday.

From 2025 to 2035, China's shale gas output will grow by an average of 33 percent every year. By 2035, China and the United States will provide some 85 percent of global shale gas output, according to the report.

BP's group chief economist Spencer Dale attributed the explosive growth to China's rich shale gas resources, government policy support to exploration, and China's current achievements in shale gas development.

Exploration of shale gas, an unconventional source of natural gas, has gathered pace in China as the government promotes the use of clean energy, but high exploration costs and sophisticated technological requirements have substantially restrained the sector's growth.

Whether China can bring in more private capital to the industry is the key for future development, Dale said.

The report also forecast that China will overtake the United States as the largest oil consumer around 2030.

By 2035, China's dependence rates on imports of oil and natural gas will rise to 75 percent and 40 percent, from the current 60 percent and 30 percent, respectively, making China the world's biggest energy importer, according to the report.

The share of coal in China's energy mix will fall to 51 percent from the current 68 percent by 2035. Natural gas will take up 12 percent and oil 18 percent, said the report.