Utility-scale solar power generation alone is expected to increase by 45 percent by 2017, according to the Energy Department. Administration officials express an ambition to make wind power the source of more than a third of the American electricity supply by 2050.

In China, the world’s biggest greenhouse gas emitter, the government implemented a new rule that no matter how low world crude oil prices may fall, the price of gasoline and diesel will continue to be set as though the world price of oil were still $40 a barrel. The goal is to prevent gasoline and diesel from becoming so cheap that China’s citizens would start consuming it indiscriminately.

China’s heavily state-owned refining industry will also not be allowed to keep the extra profits from buying crude oil cheaply and selling gasoline and diesel as though the crude oil still cost $40 a barrel. Instead, the Chinese government will take the extra refining profit margin and put the money into a special fund for energy conservation and pollution control.

But across the globe, the picture is not entirely rosy for zero-emission technologies.

Several nuclear power plants, which emit virtually no greenhouse gases, have closed in the United States in recent years, and few are under construction in part because of the competition of cheap natural gas.

Low oil prices also jeopardize the development of alternative fuels to replace petroleum in transportation and industry, including the advanced biofuels that once looked so promising. Cheap oil also reduces the price of diesel, the primary competitor of renewables in spreading electricity generation to impoverished rural areas of Africa and Southeast Asia.