On a lake created by the collapse of abandoned coal mines, China has built the world’s largest floating solar project, enough to provide light and air conditioning to much of a nearby city. The provincial government wants to expand the effort to more than a dozen sites, which collectively would produce the same amount of power as a full-size commercial nuclear reactor.

The project reflects China’s effort to reshape the world order in renewable energy as the United States retreats. Such technological expertise will form the infrastructure backbone needed for countries to meet their climate goals, making China the energy partner of choice for many nation.

The wave-proof solar panels are an affordable and viable option for power-hungry countries. Delegations from Japan, Taiwan, Vietnam, Singapore and elsewhere have come to study the project while the maker, Sungrow, prepares to license the technology for overseas sale. The panels at the lake in Liulong are made to be waterproof. Xiao Fuqin, the chief engineer at Sungrow’s floating solar panel project, said delegations arrive almost daily from around China and across Asia to examine the nitty-gritty specifications, like how to lay large power cables underwater to connect many panels.

“This technology shows that China is keeping the leading role in solar, as it has for many years,” Mr. Xiao said. “We have been the pioneers, and pushed our industry another small step forward.”