A wind farm managed by Berkshire Hathaway Energy in Marshalltown, Iowa. Iowa, Kansas and the country of Denmark are the world's three leading producers of wind energy.

Saving the environment is no longer the only compelling argument for switching to renewable energy, said Michael Milken, chairman of think tank Milken Institute, who pointed out that such energy sources are now cheaper than many fossil fuels.

Today, "for two-thirds of the world, renewables are cheaper than a significant amount of carbon-based energy, so it isn't just an argument of environment, it's now just pure economics," Milken told CNBC at the Milken Institute Asia Summit in Singapore.

Investments in clean energy technology are increasing, which means that such new sources of fuel are becoming more cost efficient, he said.

"The state that has the lowest cost energy, Texas, is the state in the United States that has the largest amount of wind power," said Milken.

Renewable energy sources from hydropower and solar energy to wind are now taking off in a big way, defying critics who just a decade ago were skeptical about those new energy sources, he pointed out.

"If you go to the United States a decade ago, you had the leaders testify that there would be no substitute for coal, that renewables would make up a very small part of the United States' (energy mix)," Milken said.