PREPA's Central Palo Seco power station in San Juan, Puerto Rico. The utility's bondholders want to raise rates. That's a challenge when the median income is about half that of Mississippi, yet the U.S. territory's energy costs are among the highest in the nation. Alvin Baez-Hernandez/Reuters/Landov hide caption

itoggle caption Alvin Baez-Hernandez/Reuters/Landov

Oil pump jacks in Williston, N.D., in December. Oil prices have been on the rise, but some analysts say the global economic slowdown, fracking and the rise of alternative energy will mean less demand and lower prices. Eric Gay/AP hide caption

itoggle caption Eric Gay/AP

A photo released by Tesla shows its new Powerwall lithium-ion battery pack mounted on the wall (left) of a garage behind one of the company's electric cars. Tesla Energy hide caption

itoggle caption Tesla Energy

Austin Holland, research seismologist at the Oklahoma Geological Survey, gestures to a chart of Oklahoma earthquakes in June 2014 as he talks about recent earthquake activity at his offices at the University of Oklahoma in Norman, Okla. The state had three times as many earthquakes as California last year. Sue Ogrocki/AP hide caption

itoggle caption Sue Ogrocki/AP

Leo Thompson stands in front of his isolated home, where he has lived for 35 years, on the Navajo Nation reservation. Like an estimated 18,000 Navajos homes, his his isn't connected to the electrical grid — it's a half-mile from the nearest line — and until recently Thompson used a generator for power. Ibby Caputo for NPR hide caption

itoggle caption Ibby Caputo for NPR

Geologists Dave Tucker (left) and Pete Stelling at the Mount Baker hot springs in Washington's Cascade Mountains. The springs are within the large tract of federal land that could soon be open for geothermal development. Ashley Ahearn/KUOW hide caption

itoggle caption Ashley Ahearn/KUOW

Students at the Pennsylvania College of Technology are learning a technique called "tripping pipe," moving a pipe from a stack into a horizontal position and lowering it down into a well. The students train on a practice drilling rig to learn how to be roustabouts. Jeff Brady/NPR hide caption

itoggle caption Jeff Brady/NPR

Night in Port-au-Prince, Haiti. Analysts warn a sudden energy shortage in the Caribbean could create security problems not far from U.S. shores and even trigger mass migration. But thanks to its domestic energy boom, the U.S. has a rare opportunity to get out in front of the crisis and possibly build some goodwill of its own. Hector Retamal/AFP/Getty Images hide caption

itoggle caption Hector Retamal/AFP/Getty Images