INDIANTOWN, Fla. — In former swamplands teaming with otters and wild hogs, one of the nation’s biggest utilities is running an experiment in the future of renewable power.

Oil prices dropped below $70 a barrel for the first time in 14 months on Thursday, prompting the OPEC cartel to call for an emergency meeting next week to establish some stability in prices that have swung wildly along with the stock market this year.

Exxon Mobil reported the second-best quarterly profit in its history on Thursday — and investors could barely hide their disappointment.

As oil prices soared to record levels in recent years, basic economics suggested that consumption would fall and supplies would rise as producers drilled for more oil.

Capping a relentless rise in recent years, oil prices hit an all-time high during the day on Monday, then pulled back to close below the record.