China has increased both the efficiency and sources of its energy supply, according to a panel of experts on Tuesday.

Participants at the International Energy Agency (IEA) World Energy Outlook 2015 supported China's efforts to increase efficiency and to diversify its new energy sources. They also discussed the outlook for the country's energy use at a forum at Columbia University in New York.

Faith Birol, executive director of the IEA, said that China has demonstrated two positive tendencies for new energy development.

The first is increased efficiency, said Birol. "The Chinese government is the most efficient policy-implementer in energy strategy, and the Chinese economy is becoming increasingly efficiency-oriented," said Birol. "Chinese energy strategy is becoming more efficient."

China's energy components until this year mainly consisted of two sources: coal and oil, Birol said.

"The energy market in China is becoming more diverse, and this is the second tendency for the future Chinese energy blueprint," he said.

According to the IEA's forecast for the next 25 years of energy use by China, a much wider spectrum of new energy has gradually penetrated the Chinese economy.

Nuclear power forms the backbone of the new strategy. Birol said that approximately half of the world's nuclear plants were located on the Chinese mainland. Renewable energy sources such as wind and solar are thriving because of government subsidies.

China also won't remain the world's largest consumer of energy. India will replace China as the world's largest oil importer and coal consumer in the next 25 years, according to Birol.

In the past, the drivers of renewable energies were the United States and Europe. However, China and India have emerged in the past two years as strong supporters of renewable energy, Birol said.

Birol said renewable energy will account for half of the additional global power generation and overtake coal around 2030 to become the largest power source of global energy.

Birol said that global coal consumption would be about 10,000 terawatt hours (twh) in 2015 and would increase to 12,000 twh in 2040, a steady and slight growth.

Consumption of renewable energy, however, about 5,500 twh in 2015, will expand to 13,500 twh in 2040 in the next 25 years.

"Hydropower used to be the main form of renewable energies, but now solar and wind are gradually the majority", said Birol, referring to China's energy focus changing from dam-based power-plants to solar, wind and biofuels.

Long Yifan in New York contributed to this story.