America's energy billionaires

Aubrey McClendon has a solution to the nation's energy problems: natural gas.

"It's ready to rescue our economy, enhance national security and reduce pollution," says the slim gray-haired Oklahoman in a television ad. It's also ready to make McClendon, already a billionaire, even richer.

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McClendon is the chief executive of Chesapeake Energy, one of the country's biggest natural gas producers. In our most recent Forbes 400 list, calculated at the end of August, we valued his net worth at $3.0 billion, much of it coming from his 32 million shares of Chesapeake.

McClendon is one of 38 men and women on this year's Forbes 400 list who owe much of their fortunes to energy. The cumulative fortune of these power players is $161.9 billion.

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Another one you can spot on television is T. Boone Pickens. The Texas oilman is spending $58 million of his own money to tout his plan for our nation's energy future. He wants to replace more than a third of the U.S.'s oil usage with energy from wind, natural gas and other sources. Pickens says the shift will help the U.S. wean itself from a crippling addiction to foreign oil.

It's not just altruism. Pickens is also positioning himself to grow his $3.1 billion fortune. His hedge fund is investing in renewable energy companies like Exco Resources and Clean Energy Fuels. One Pickens- backed company is spending $2 billion to buy nearly 700 wind turbines in a plan to build the world's largest wind farm.

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At the top of our list of America's energy billionaires are a pair of brothers. Charles and David Koch each boast a fortune of $19 billion. Their father Fred invented a method of turning heavy oil into gasoline. Charles, David and their two other brothers inherited Koch Industries after their father's death in 1967.

Charles still serves as the company's chief executive. David serves as the executive vice president. Although the company's interests have branched into fertilizers, consumer products and more, it's still a major energy player. Koch subsidiary Flint Hills Resources operates refineries throughout the United States that can process more than 800,000 barrels of oil today.

Moneyed energy men are nothing new. The book All The Money In The World estimates that John D. Rockefeller is the richest American ever when net worths are adjusted for inflation. His fortune would be worth $305.3 billion in today's dollars. Rockefeller, who died in 1937, built the oil and gas giant Standard Oil, from which Exxon Mobil and Chevron descended.

The Rockefeller fortune is now dispersed among the approximately 300 adult family members. One makes the Forbes 400. David Rockefeller Sr. ranked as the 144th wealthiest American with a fortune of $2.9 billion. That's up $200 million from the past year thanks to some diversification. The New Yorker benefited from gains in his real estate holdings and museum-worthy art collection, which includes Monet, Matisse and Renoir.

Another oil baron heir cracking our list is Gordon Getty. He inherited Getty Oil from his father, which he then sold to Texaco for $10 billion. The father of seven now likes to spend his time composing music for operas. It's a passion he can easily support. Getty ranks 163rd on the Forbes 400 with a net worth of $2.5 billion.