Beijing, China | As the United States was withdrawing from the Paris climate pact, China's clean energy ambitions were being reflected in the launch of the world's largest floating solar farm.

The 40-megawatt power plant has 160,000 panels resting on a lake that emerged after the collapse of a coal mine in central Anhui province.

It is part of Beijing's effort to wean itself off a fossil fuel dependency that has made it the world's top carbon emitter, with two-thirds of its electricity still fuelled by coal.

The solar facility went online around the time of President Donald Trump's much-criticised June 2 decision to withdraw from the international accord aimed at saving the planet from climate change catastrophe.

His move shifted the spotlight onto China and whether it will take on the leadership mantle in the fight against global warming.

Days after his announcement -- and by coincidence -- Beijing hosted an international conference on clean energy.

It was an opportunity for China, which already produces two-thirds of the world's solar panels, to boast of its commitment to accelerating investment and reforms for greater use of renewable energies.

"The US's withdrawal from the Paris agreement offers China an unprecedented opportunity to take the lead in climate change," energy expert Frank Yu of Wood Mackenzie consultancy told AFP.

- China dominating -The Beijing forum put a spotlight on efforts by Chinese authorities and companies to develop renewable energy.

"Beijing may feel like it's dominating the game", especially because "China is already moving rapidly -- with or without the US -- in terms of investments" and innovation, Alex Perera, director of the WRI Energy Program, told AFP.

It has been the world's largest investor in clean energy since 2012, spending $88 billion on wind and solar power last year, according to Bloomberg News.

China's solar capacity more than doubled in 2016. The official goal is for 20 percent of Chinese power consumption to come from low-emission energy, including nuclear, by 2030, compared to 11 percent currently.

"We must take these promises seriously," said Helen Clarkson, president of the Climate Group.

Beijing hopes to combat endemic air pollution, but is also motivated by financial interests, as the country "is already reaping the economic benefits" of clean energy, Clarkson said.

- 'Wake people up' -With the US administration out of the Paris pact, China has signalled its readiness to deal with US local governments to advance its climate agenda.

California Governor Jerry Brown used the Beijing conference to seek partnerships with China on climate change, and was given the red-carpet treatment by Chinese President Xi Jinping.

Brown, who has criticised Trump's June 2 decision, signed a memorandum of understanding with Xi as well as an agreement with Sichuan province.

"I'm trying to wake people up to deal with climate change," Brown told AFP in Beijing.

"China is an ally in that and it has tremendous resources and I want to work with those resources in a way that will accelerate our climate action," he said.

Xie Zhenhua, China's top climate negotiator, made it clear at the clean energy forum: "We will not only continue to strengthen cooperation with California, but also strengthen the concrete cooperation with other US states, cities, enterprises and scientific research institutions in fields including clean energy."

US energy secretary Rick Perry was also at the forum but failed to get the same reception as Brown, meeting China's seventh-ranked official instead of Xi.

Perry insisted Washington was not stepping back from its clean energy commitment.

"It's good for China to step in and take on the issue and to attempt to be the leader in the world for emissions reduction," he said, adding: "The fact of the matter is the US is number one still."